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root/OpenMD/trunk/src/nonbonded/Electrostatic.cpp
Revision: 1922
Committed: Mon Aug 5 13:41:15 2013 UTC (11 years, 9 months ago) by gezelter
File size: 54531 byte(s)
Log Message:
Fixed a few ewald bugs

File Contents

# Content
1 /*
2 * Copyright (c) 2005 The University of Notre Dame. All Rights Reserved.
3 *
4 * The University of Notre Dame grants you ("Licensee") a
5 * non-exclusive, royalty free, license to use, modify and
6 * redistribute this software in source and binary code form, provided
7 * that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the
15 * distribution.
16 *
17 * This software is provided "AS IS," without a warranty of any
18 * kind. All express or implied conditions, representations and
19 * warranties, including any implied warranty of merchantability,
20 * fitness for a particular purpose or non-infringement, are hereby
21 * excluded. The University of Notre Dame and its licensors shall not
22 * be liable for any damages suffered by licensee as a result of
23 * using, modifying or distributing the software or its
24 * derivatives. In no event will the University of Notre Dame or its
25 * licensors be liable for any lost revenue, profit or data, or for
26 * direct, indirect, special, consequential, incidental or punitive
27 * damages, however caused and regardless of the theory of liability,
28 * arising out of the use of or inability to use software, even if the
29 * University of Notre Dame has been advised of the possibility of
30 * such damages.
31 *
32 * SUPPORT OPEN SCIENCE! If you use OpenMD or its source code in your
33 * research, please cite the appropriate papers when you publish your
34 * work. Good starting points are:
35 *
36 * [1] Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).
37 * [2] Fennell & Gezelter, J. Chem. Phys. 124 234104 (2006).
38 * [3] Sun, Lin & Gezelter, J. Chem. Phys. 128, 234107 (2008).
39 * [4] Kuang & Gezelter, J. Chem. Phys. 133, 164101 (2010).
40 * [5] Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
41 */
42
43 #include <stdio.h>
44 #include <string.h>
45
46 #include <cmath>
47 #include <numeric>
48 #include "nonbonded/Electrostatic.hpp"
49 #include "utils/simError.h"
50 #include "types/NonBondedInteractionType.hpp"
51 #include "types/FixedChargeAdapter.hpp"
52 #include "types/FluctuatingChargeAdapter.hpp"
53 #include "types/MultipoleAdapter.hpp"
54 #include "io/Globals.hpp"
55 #include "nonbonded/SlaterIntegrals.hpp"
56 #include "utils/PhysicalConstants.hpp"
57 #include "math/erfc.hpp"
58 #include "math/SquareMatrix.hpp"
59 #include "primitives/Molecule.hpp"
60
61
62 namespace OpenMD {
63
64 Electrostatic::Electrostatic(): name_("Electrostatic"), initialized_(false),
65 forceField_(NULL), info_(NULL),
66 haveCutoffRadius_(false),
67 haveDampingAlpha_(false),
68 haveDielectric_(false),
69 haveElectroSplines_(false)
70 {}
71
72 void Electrostatic::initialize() {
73
74 Globals* simParams_ = info_->getSimParams();
75
76 summationMap_["HARD"] = esm_HARD;
77 summationMap_["NONE"] = esm_HARD;
78 summationMap_["SWITCHING_FUNCTION"] = esm_SWITCHING_FUNCTION;
79 summationMap_["SHIFTED_POTENTIAL"] = esm_SHIFTED_POTENTIAL;
80 summationMap_["SHIFTED_FORCE"] = esm_SHIFTED_FORCE;
81 summationMap_["TAYLOR_SHIFTED"] = esm_TAYLOR_SHIFTED;
82 summationMap_["REACTION_FIELD"] = esm_REACTION_FIELD;
83 summationMap_["EWALD_FULL"] = esm_EWALD_FULL;
84 summationMap_["EWALD_PME"] = esm_EWALD_PME;
85 summationMap_["EWALD_SPME"] = esm_EWALD_SPME;
86 screeningMap_["DAMPED"] = DAMPED;
87 screeningMap_["UNDAMPED"] = UNDAMPED;
88
89 // these prefactors convert the multipole interactions into kcal / mol
90 // all were computed assuming distances are measured in angstroms
91 // Charge-Charge, assuming charges are measured in electrons
92 pre11_ = 332.0637778;
93 // Charge-Dipole, assuming charges are measured in electrons, and
94 // dipoles are measured in debyes
95 pre12_ = 69.13373;
96 // Dipole-Dipole, assuming dipoles are measured in Debye
97 pre22_ = 14.39325;
98 // Charge-Quadrupole, assuming charges are measured in electrons, and
99 // quadrupoles are measured in 10^-26 esu cm^2
100 // This unit is also known affectionately as an esu centibarn.
101 pre14_ = 69.13373;
102 // Dipole-Quadrupole, assuming dipoles are measured in debyes and
103 // quadrupoles in esu centibarns:
104 pre24_ = 14.39325;
105 // Quadrupole-Quadrupole, assuming esu centibarns:
106 pre44_ = 14.39325;
107
108 // conversions for the simulation box dipole moment
109 chargeToC_ = 1.60217733e-19;
110 angstromToM_ = 1.0e-10;
111 debyeToCm_ = 3.33564095198e-30;
112
113 // Default number of points for electrostatic splines
114 np_ = 100;
115
116 // variables to handle different summation methods for long-range
117 // electrostatics:
118 summationMethod_ = esm_HARD;
119 screeningMethod_ = UNDAMPED;
120 dielectric_ = 1.0;
121
122 // check the summation method:
123 if (simParams_->haveElectrostaticSummationMethod()) {
124 string myMethod = simParams_->getElectrostaticSummationMethod();
125 toUpper(myMethod);
126 map<string, ElectrostaticSummationMethod>::iterator i;
127 i = summationMap_.find(myMethod);
128 if ( i != summationMap_.end() ) {
129 summationMethod_ = (*i).second;
130 } else {
131 // throw error
132 sprintf( painCave.errMsg,
133 "Electrostatic::initialize: Unknown electrostaticSummationMethod.\n"
134 "\t(Input file specified %s .)\n"
135 "\telectrostaticSummationMethod must be one of: \"hard\",\n"
136 "\t\"shifted_potential\", \"shifted_force\",\n"
137 "\t\"taylor_shifted\", or \"reaction_field\".\n",
138 myMethod.c_str() );
139 painCave.isFatal = 1;
140 simError();
141 }
142 } else {
143 // set ElectrostaticSummationMethod to the cutoffMethod:
144 if (simParams_->haveCutoffMethod()){
145 string myMethod = simParams_->getCutoffMethod();
146 toUpper(myMethod);
147 map<string, ElectrostaticSummationMethod>::iterator i;
148 i = summationMap_.find(myMethod);
149 if ( i != summationMap_.end() ) {
150 summationMethod_ = (*i).second;
151 }
152 }
153 }
154
155 if (summationMethod_ == esm_REACTION_FIELD) {
156 if (!simParams_->haveDielectric()) {
157 // throw warning
158 sprintf( painCave.errMsg,
159 "SimInfo warning: dielectric was not specified in the input file\n\tfor the reaction field correction method.\n"
160 "\tA default value of %f will be used for the dielectric.\n", dielectric_);
161 painCave.isFatal = 0;
162 painCave.severity = OPENMD_INFO;
163 simError();
164 } else {
165 dielectric_ = simParams_->getDielectric();
166 }
167 haveDielectric_ = true;
168 }
169
170 if (simParams_->haveElectrostaticScreeningMethod()) {
171 string myScreen = simParams_->getElectrostaticScreeningMethod();
172 toUpper(myScreen);
173 map<string, ElectrostaticScreeningMethod>::iterator i;
174 i = screeningMap_.find(myScreen);
175 if ( i != screeningMap_.end()) {
176 screeningMethod_ = (*i).second;
177 } else {
178 sprintf( painCave.errMsg,
179 "SimInfo error: Unknown electrostaticScreeningMethod.\n"
180 "\t(Input file specified %s .)\n"
181 "\telectrostaticScreeningMethod must be one of: \"undamped\"\n"
182 "or \"damped\".\n", myScreen.c_str() );
183 painCave.isFatal = 1;
184 simError();
185 }
186 }
187
188 // check to make sure a cutoff value has been set:
189 if (!haveCutoffRadius_) {
190 sprintf( painCave.errMsg, "Electrostatic::initialize has no Default "
191 "Cutoff value!\n");
192 painCave.severity = OPENMD_ERROR;
193 painCave.isFatal = 1;
194 simError();
195 }
196
197 if (screeningMethod_ == DAMPED || summationMethod_ == esm_EWALD_FULL) {
198 if (!simParams_->haveDampingAlpha()) {
199 // first set a cutoff dependent alpha value
200 // we assume alpha depends linearly with rcut from 0 to 20.5 ang
201 dampingAlpha_ = 0.425 - cutoffRadius_* 0.02;
202 if (dampingAlpha_ < 0.0) dampingAlpha_ = 0.0;
203 // throw warning
204 sprintf( painCave.errMsg,
205 "Electrostatic::initialize: dampingAlpha was not specified in the\n"
206 "\tinput file. A default value of %f (1/ang) will be used for the\n"
207 "\tcutoff of %f (ang).\n",
208 dampingAlpha_, cutoffRadius_);
209 painCave.severity = OPENMD_INFO;
210 painCave.isFatal = 0;
211 simError();
212 } else {
213 dampingAlpha_ = simParams_->getDampingAlpha();
214 }
215 haveDampingAlpha_ = true;
216 }
217
218
219 Etypes.clear();
220 Etids.clear();
221 FQtypes.clear();
222 FQtids.clear();
223 ElectrostaticMap.clear();
224 Jij.clear();
225 nElectro_ = 0;
226 nFlucq_ = 0;
227
228 Etids.resize( forceField_->getNAtomType(), -1);
229 FQtids.resize( forceField_->getNAtomType(), -1);
230
231 set<AtomType*>::iterator at;
232 for (at = simTypes_.begin(); at != simTypes_.end(); ++at) {
233 if ((*at)->isElectrostatic()) nElectro_++;
234 if ((*at)->isFluctuatingCharge()) nFlucq_++;
235 }
236
237 Jij.resize(nFlucq_);
238
239 for (at = simTypes_.begin(); at != simTypes_.end(); ++at) {
240 if ((*at)->isElectrostatic()) addType(*at);
241 }
242
243 if (summationMethod_ == esm_REACTION_FIELD) {
244 preRF_ = (dielectric_ - 1.0) /
245 ((2.0 * dielectric_ + 1.0) * pow(cutoffRadius_,3) );
246 }
247
248 RealType b0c, b1c, b2c, b3c, b4c, b5c;
249 RealType db0c_1, db0c_2, db0c_3, db0c_4, db0c_5;
250 RealType a2, expTerm, invArootPi;
251
252 RealType r = cutoffRadius_;
253 RealType r2 = r * r;
254 RealType ric = 1.0 / r;
255 RealType ric2 = ric * ric;
256
257 if (screeningMethod_ == DAMPED) {
258 a2 = dampingAlpha_ * dampingAlpha_;
259 invArootPi = 1.0 / (dampingAlpha_ * sqrt(M_PI));
260 expTerm = exp(-a2 * r2);
261 // values of Smith's B_l functions at the cutoff radius:
262 b0c = erfc(dampingAlpha_ * r) / r;
263 b1c = ( b0c + 2.0*a2 * expTerm * invArootPi) / r2;
264 b2c = (3.0 * b1c + pow(2.0*a2, 2) * expTerm * invArootPi) / r2;
265 b3c = (5.0 * b2c + pow(2.0*a2, 3) * expTerm * invArootPi) / r2;
266 b4c = (7.0 * b3c + pow(2.0*a2, 4) * expTerm * invArootPi) / r2;
267 b5c = (9.0 * b4c + pow(2.0*a2, 5) * expTerm * invArootPi) / r2;
268 // Half the Smith self piece:
269 selfMult1_ = - a2 * invArootPi;
270 selfMult2_ = - 2.0 * a2 * a2 * invArootPi / 3.0;
271 selfMult4_ = - 4.0 * a2 * a2 * a2 * invArootPi / 5.0;
272 } else {
273 a2 = 0.0;
274 b0c = 1.0 / r;
275 b1c = ( b0c) / r2;
276 b2c = (3.0 * b1c) / r2;
277 b3c = (5.0 * b2c) / r2;
278 b4c = (7.0 * b3c) / r2;
279 b5c = (9.0 * b4c) / r2;
280 selfMult1_ = 0.0;
281 selfMult2_ = 0.0;
282 selfMult4_ = 0.0;
283 }
284
285 // higher derivatives of B_0 at the cutoff radius:
286 db0c_1 = -r * b1c;
287 db0c_2 = -b1c + r2 * b2c;
288 db0c_3 = 3.0*r*b2c - r2*r*b3c;
289 db0c_4 = 3.0*b2c - 6.0*r2*b3c + r2*r2*b4c;
290 db0c_5 = -15.0*r*b3c + 10.0*r2*r*b4c - r2*r2*r*b5c;
291
292 if (summationMethod_ != esm_EWALD_FULL) {
293 selfMult1_ -= b0c;
294 selfMult2_ += (db0c_2 + 2.0*db0c_1*ric) / 3.0;
295 selfMult4_ -= (db0c_4 + 4.0*db0c_3*ric) / 15.0;
296 }
297
298 // working variables for the splines:
299 RealType ri, ri2;
300 RealType b0, b1, b2, b3, b4, b5;
301 RealType db0_1, db0_2, db0_3, db0_4, db0_5;
302 RealType f, fc, f0;
303 RealType g, gc, g0, g1, g2, g3, g4;
304 RealType h, hc, h1, h2, h3, h4;
305 RealType s, sc, s2, s3, s4;
306 RealType t, tc, t3, t4;
307 RealType u, uc, u4;
308
309 // working variables for Taylor expansion:
310 RealType rmRc, rmRc2, rmRc3, rmRc4;
311
312 // Approximate using splines using a maximum of 0.1 Angstroms
313 // between points.
314 int nptest = int((cutoffRadius_ + 2.0) / 0.1);
315 np_ = (np_ > nptest) ? np_ : nptest;
316
317 // Add a 2 angstrom safety window to deal with cutoffGroups that
318 // have charged atoms longer than the cutoffRadius away from each
319 // other. Splining is almost certainly the best choice here.
320 // Direct calls to erfc would be preferrable if it is a very fast
321 // implementation.
322
323 RealType dx = (cutoffRadius_ + 2.0) / RealType(np_);
324
325 // Storage vectors for the computed functions
326 vector<RealType> rv;
327 vector<RealType> v01v;
328 vector<RealType> v11v;
329 vector<RealType> v21v, v22v;
330 vector<RealType> v31v, v32v;
331 vector<RealType> v41v, v42v, v43v;
332
333 for (int i = 1; i < np_ + 1; i++) {
334 r = RealType(i) * dx;
335 rv.push_back(r);
336
337 ri = 1.0 / r;
338 ri2 = ri * ri;
339
340 r2 = r * r;
341 expTerm = exp(-a2 * r2);
342
343 // Taylor expansion factors (no need for factorials this way):
344 rmRc = r - cutoffRadius_;
345 rmRc2 = rmRc * rmRc / 2.0;
346 rmRc3 = rmRc2 * rmRc / 3.0;
347 rmRc4 = rmRc3 * rmRc / 4.0;
348
349 // values of Smith's B_l functions at r:
350 if (screeningMethod_ == DAMPED) {
351 b0 = erfc(dampingAlpha_ * r) * ri;
352 b1 = ( b0 + 2.0*a2 * expTerm * invArootPi) * ri2;
353 b2 = (3.0 * b1 + pow(2.0*a2, 2) * expTerm * invArootPi) * ri2;
354 b3 = (5.0 * b2 + pow(2.0*a2, 3) * expTerm * invArootPi) * ri2;
355 b4 = (7.0 * b3 + pow(2.0*a2, 4) * expTerm * invArootPi) * ri2;
356 b5 = (9.0 * b4 + pow(2.0*a2, 5) * expTerm * invArootPi) * ri2;
357 } else {
358 b0 = ri;
359 b1 = ( b0) * ri2;
360 b2 = (3.0 * b1) * ri2;
361 b3 = (5.0 * b2) * ri2;
362 b4 = (7.0 * b3) * ri2;
363 b5 = (9.0 * b4) * ri2;
364 }
365
366 // higher derivatives of B_0 at r:
367 db0_1 = -r * b1;
368 db0_2 = -b1 + r2 * b2;
369 db0_3 = 3.0*r*b2 - r2*r*b3;
370 db0_4 = 3.0*b2 - 6.0*r2*b3 + r2*r2*b4;
371 db0_5 = -15.0*r*b3 + 10.0*r2*r*b4 - r2*r2*r*b5;
372
373 f = b0;
374 fc = b0c;
375 f0 = f - fc - rmRc*db0c_1;
376
377 g = db0_1;
378 gc = db0c_1;
379 g0 = g - gc;
380 g1 = g0 - rmRc *db0c_2;
381 g2 = g1 - rmRc2*db0c_3;
382 g3 = g2 - rmRc3*db0c_4;
383 g4 = g3 - rmRc4*db0c_5;
384
385 h = db0_2;
386 hc = db0c_2;
387 h1 = h - hc;
388 h2 = h1 - rmRc *db0c_3;
389 h3 = h2 - rmRc2*db0c_4;
390 h4 = h3 - rmRc3*db0c_5;
391
392 s = db0_3;
393 sc = db0c_3;
394 s2 = s - sc;
395 s3 = s2 - rmRc *db0c_4;
396 s4 = s3 - rmRc2*db0c_5;
397
398 t = db0_4;
399 tc = db0c_4;
400 t3 = t - tc;
401 t4 = t3 - rmRc *db0c_5;
402
403 u = db0_5;
404 uc = db0c_5;
405 u4 = u - uc;
406
407 // in what follows below, the various v functions are used for
408 // potentials and torques, while the w functions show up in the
409 // forces.
410
411 switch (summationMethod_) {
412 case esm_SHIFTED_FORCE:
413
414 v01 = f - fc - rmRc*gc;
415 v11 = g - gc - rmRc*hc;
416 v21 = g*ri - gc*ric - rmRc*(hc - gc*ric)*ric;
417 v22 = h - g*ri - (hc - gc*ric) - rmRc*(sc - (hc - gc*ric)*ric);
418 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric - rmRc*(sc-2.0*(hc-gc*ric)*ric)*ric;
419 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric)
420 - rmRc*(tc - 3.0*(sc-2.0*(hc-gc*ric)*ric)*ric);
421 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2
422 - rmRc*(sc - 3.0*(hc-gc*ric)*ric)*ric2;
423 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric
424 - rmRc*(tc - (4.0*sc - 9.0*(hc - gc*ric)*ric)*ric)*ric;
425
426 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
427 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric)
428 - rmRc*(uc-3.0*(2.0*tc - (7.0*sc - 15.0*(hc - gc*ric)*ric)*ric)*ric);
429
430 dv01 = g - gc;
431 dv11 = h - hc;
432 dv21 = (h - g*ri)*ri - (hc - gc*ric)*ric;
433 dv22 = (s - (h - g*ri)*ri) - (sc - (hc - gc*ric)*ric);
434 dv31 = (s - 2.0*(h-g*ri)*ri)*ri - (sc - 2.0*(hc-gc*ric)*ric)*ric;
435 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri)
436 - (tc - 3.0*(sc-2.0*(hc-gc*ric)*ric)*ric);
437 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2 - (sc - 3.0*(hc - gc*ric)*ric)*ric2;
438 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri
439 - (tc - (4.0*sc - 9.0*(hc-gc*ric)*ric)*ric)*ric;
440 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri)
441 - (uc - 3.0*(2.0*tc - (7.0*sc - 15.0*(hc - gc*ric)*ric)*ric)*ric);
442
443 break;
444
445 case esm_TAYLOR_SHIFTED:
446
447 v01 = f0;
448 v11 = g1;
449 v21 = g2 * ri;
450 v22 = h2 - v21;
451 v31 = (h3 - g3 * ri) * ri;
452 v32 = s3 - 3.0*v31;
453 v41 = (h4 - g4 * ri) * ri2;
454 v42 = s4 * ri - 3.0*v41;
455 v43 = t4 - 6.0*v42 - 3.0*v41;
456
457 dv01 = g0;
458 dv11 = h1;
459 dv21 = (h2 - g2*ri)*ri;
460 dv22 = (s2 - (h2 - g2*ri)*ri);
461 dv31 = (s3 - 2.0*(h3-g3*ri)*ri)*ri;
462 dv32 = (t3 - 3.0*(s3-2.0*(h3-g3*ri)*ri)*ri);
463 dv41 = (s4 - 3.0*(h4 - g4*ri)*ri)*ri2;
464 dv42 = (t4 - (4.0*s4 - 9.0*(h4-g4*ri)*ri)*ri)*ri;
465 dv43 = (u4 - 3.0*(2.0*t4 - (7.0*s4 - 15.0*(h4 - g4*ri)*ri)*ri)*ri);
466
467 break;
468
469 case esm_SHIFTED_POTENTIAL:
470
471 v01 = f - fc;
472 v11 = g - gc;
473 v21 = g*ri - gc*ric;
474 v22 = h - g*ri - (hc - gc*ric);
475 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric;
476 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric);
477 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2;
478 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric;
479 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
480 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric);
481
482 dv01 = g;
483 dv11 = h;
484 dv21 = (h - g*ri)*ri;
485 dv22 = (s - (h - g*ri)*ri);
486 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
487 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
488 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
489 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
490 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
491
492 break;
493
494 case esm_SWITCHING_FUNCTION:
495 case esm_HARD:
496 case esm_EWALD_FULL:
497
498 v01 = f;
499 v11 = g;
500 v21 = g*ri;
501 v22 = h - g*ri;
502 v31 = (h-g*ri)*ri;
503 v32 = (s - 3.0*(h-g*ri)*ri);
504 v41 = (h - g*ri)*ri2;
505 v42 = (s-3.0*(h-g*ri)*ri)*ri;
506 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri);
507
508 dv01 = g;
509 dv11 = h;
510 dv21 = (h - g*ri)*ri;
511 dv22 = (s - (h - g*ri)*ri);
512 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
513 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
514 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
515 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
516 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
517
518 break;
519
520 case esm_REACTION_FIELD:
521
522 // following DL_POLY's lead for shifting the image charge potential:
523 f = b0 + preRF_ * r2;
524 fc = b0c + preRF_ * cutoffRadius_ * cutoffRadius_;
525
526 g = db0_1 + preRF_ * 2.0 * r;
527 gc = db0c_1 + preRF_ * 2.0 * cutoffRadius_;
528
529 h = db0_2 + preRF_ * 2.0;
530 hc = db0c_2 + preRF_ * 2.0;
531
532 v01 = f - fc;
533 v11 = g - gc;
534 v21 = g*ri - gc*ric;
535 v22 = h - g*ri - (hc - gc*ric);
536 v31 = (h-g*ri)*ri - (hc-gc*ric)*ric;
537 v32 = (s - 3.0*(h-g*ri)*ri) - (sc - 3.0*(hc-gc*ric)*ric);
538 v41 = (h - g*ri)*ri2 - (hc - gc*ric)*ric2;
539 v42 = (s-3.0*(h-g*ri)*ri)*ri - (sc-3.0*(hc-gc*ric)*ric)*ric;
540 v43 = (t - 3.0*(2.0*s - 5.0*(h - g*ri)*ri)*ri)
541 - (tc - 3.0*(2.0*sc - 5.0*(hc - gc*ric)*ric)*ric);
542
543 dv01 = g;
544 dv11 = h;
545 dv21 = (h - g*ri)*ri;
546 dv22 = (s - (h - g*ri)*ri);
547 dv31 = (s - 2.0*(h-g*ri)*ri)*ri;
548 dv32 = (t - 3.0*(s-2.0*(h-g*ri)*ri)*ri);
549 dv41 = (s - 3.0*(h - g*ri)*ri)*ri2;
550 dv42 = (t - (4.0*s - 9.0*(h-g*ri)*ri)*ri)*ri;
551 dv43 = (u - 3.0*(2.0*t - (7.0*s - 15.0*(h - g*ri)*ri)*ri)*ri);
552
553 break;
554
555 case esm_EWALD_PME:
556 case esm_EWALD_SPME:
557 default :
558 map<string, ElectrostaticSummationMethod>::iterator i;
559 std::string meth;
560 for (i = summationMap_.begin(); i != summationMap_.end(); ++i) {
561 if ((*i).second == summationMethod_) meth = (*i).first;
562 }
563 sprintf( painCave.errMsg,
564 "Electrostatic::initialize: electrostaticSummationMethod %s \n"
565 "\thas not been implemented yet. Please select one of:\n"
566 "\t\"hard\", \"shifted_potential\", or \"shifted_force\"\n",
567 meth.c_str() );
568 painCave.isFatal = 1;
569 simError();
570 break;
571 }
572
573 // Add these computed values to the storage vectors for spline creation:
574 v01v.push_back(v01);
575 v11v.push_back(v11);
576 v21v.push_back(v21);
577 v22v.push_back(v22);
578 v31v.push_back(v31);
579 v32v.push_back(v32);
580 v41v.push_back(v41);
581 v42v.push_back(v42);
582 v43v.push_back(v43);
583 }
584
585 // construct the spline structures and fill them with the values we've
586 // computed:
587
588 v01s = new CubicSpline();
589 v01s->addPoints(rv, v01v);
590 v11s = new CubicSpline();
591 v11s->addPoints(rv, v11v);
592 v21s = new CubicSpline();
593 v21s->addPoints(rv, v21v);
594 v22s = new CubicSpline();
595 v22s->addPoints(rv, v22v);
596 v31s = new CubicSpline();
597 v31s->addPoints(rv, v31v);
598 v32s = new CubicSpline();
599 v32s->addPoints(rv, v32v);
600 v41s = new CubicSpline();
601 v41s->addPoints(rv, v41v);
602 v42s = new CubicSpline();
603 v42s->addPoints(rv, v42v);
604 v43s = new CubicSpline();
605 v43s->addPoints(rv, v43v);
606
607 haveElectroSplines_ = true;
608
609 initialized_ = true;
610 }
611
612 void Electrostatic::addType(AtomType* atomType){
613
614 ElectrostaticAtomData electrostaticAtomData;
615 electrostaticAtomData.is_Charge = false;
616 electrostaticAtomData.is_Dipole = false;
617 electrostaticAtomData.is_Quadrupole = false;
618 electrostaticAtomData.is_Fluctuating = false;
619
620 FixedChargeAdapter fca = FixedChargeAdapter(atomType);
621
622 if (fca.isFixedCharge()) {
623 electrostaticAtomData.is_Charge = true;
624 electrostaticAtomData.fixedCharge = fca.getCharge();
625 }
626
627 MultipoleAdapter ma = MultipoleAdapter(atomType);
628 if (ma.isMultipole()) {
629 if (ma.isDipole()) {
630 electrostaticAtomData.is_Dipole = true;
631 electrostaticAtomData.dipole = ma.getDipole();
632 }
633 if (ma.isQuadrupole()) {
634 electrostaticAtomData.is_Quadrupole = true;
635 electrostaticAtomData.quadrupole = ma.getQuadrupole();
636 }
637 }
638
639 FluctuatingChargeAdapter fqa = FluctuatingChargeAdapter(atomType);
640
641 if (fqa.isFluctuatingCharge()) {
642 electrostaticAtomData.is_Fluctuating = true;
643 electrostaticAtomData.electronegativity = fqa.getElectronegativity();
644 electrostaticAtomData.hardness = fqa.getHardness();
645 electrostaticAtomData.slaterN = fqa.getSlaterN();
646 electrostaticAtomData.slaterZeta = fqa.getSlaterZeta();
647 }
648
649 int atid = atomType->getIdent();
650 int etid = Etypes.size();
651 int fqtid = FQtypes.size();
652
653 pair<set<int>::iterator,bool> ret;
654 ret = Etypes.insert( atid );
655 if (ret.second == false) {
656 sprintf( painCave.errMsg,
657 "Electrostatic already had a previous entry with ident %d\n",
658 atid);
659 painCave.severity = OPENMD_INFO;
660 painCave.isFatal = 0;
661 simError();
662 }
663
664 Etids[ atid ] = etid;
665 ElectrostaticMap.push_back(electrostaticAtomData);
666
667 if (electrostaticAtomData.is_Fluctuating) {
668 ret = FQtypes.insert( atid );
669 if (ret.second == false) {
670 sprintf( painCave.errMsg,
671 "Electrostatic already had a previous fluctuating charge entry with ident %d\n",
672 atid );
673 painCave.severity = OPENMD_INFO;
674 painCave.isFatal = 0;
675 simError();
676 }
677 FQtids[atid] = fqtid;
678 Jij[fqtid].resize(nFlucq_);
679
680 // Now, iterate over all known fluctuating and add to the
681 // coulomb integral map:
682
683 std::set<int>::iterator it;
684 for( it = FQtypes.begin(); it != FQtypes.end(); ++it) {
685 int etid2 = Etids[ (*it) ];
686 int fqtid2 = FQtids[ (*it) ];
687 ElectrostaticAtomData eaData2 = ElectrostaticMap[ etid2 ];
688 RealType a = electrostaticAtomData.slaterZeta;
689 RealType b = eaData2.slaterZeta;
690 int m = electrostaticAtomData.slaterN;
691 int n = eaData2.slaterN;
692
693 // Create the spline of the coulombic integral for s-type
694 // Slater orbitals. Add a 2 angstrom safety window to deal
695 // with cutoffGroups that have charged atoms longer than the
696 // cutoffRadius away from each other.
697
698 RealType rval;
699 RealType dr = (cutoffRadius_ + 2.0) / RealType(np_ - 1);
700 vector<RealType> rvals;
701 vector<RealType> Jvals;
702 // don't start at i = 0, as rval = 0 is undefined for the
703 // slater overlap integrals.
704 for (int i = 1; i < np_+1; i++) {
705 rval = RealType(i) * dr;
706 rvals.push_back(rval);
707 Jvals.push_back(sSTOCoulInt( a, b, m, n, rval *
708 PhysicalConstants::angstromToBohr ) *
709 PhysicalConstants::hartreeToKcal );
710 }
711
712 CubicSpline* J = new CubicSpline();
713 J->addPoints(rvals, Jvals);
714 Jij[fqtid][fqtid2] = J;
715 Jij[fqtid2].resize( nFlucq_ );
716 Jij[fqtid2][fqtid] = J;
717 }
718 }
719 return;
720 }
721
722 void Electrostatic::setCutoffRadius( RealType rCut ) {
723 cutoffRadius_ = rCut;
724 haveCutoffRadius_ = true;
725 }
726
727 void Electrostatic::setElectrostaticSummationMethod( ElectrostaticSummationMethod esm ) {
728 summationMethod_ = esm;
729 }
730 void Electrostatic::setElectrostaticScreeningMethod( ElectrostaticScreeningMethod sm ) {
731 screeningMethod_ = sm;
732 }
733 void Electrostatic::setDampingAlpha( RealType alpha ) {
734 dampingAlpha_ = alpha;
735 haveDampingAlpha_ = true;
736 }
737 void Electrostatic::setReactionFieldDielectric( RealType dielectric ){
738 dielectric_ = dielectric;
739 haveDielectric_ = true;
740 }
741
742 void Electrostatic::calcForce(InteractionData &idat) {
743
744 if (!initialized_) initialize();
745
746 data1 = ElectrostaticMap[Etids[idat.atid1]];
747 data2 = ElectrostaticMap[Etids[idat.atid2]];
748
749 U = 0.0; // Potential
750 F.zero(); // Force
751 Ta.zero(); // Torque on site a
752 Tb.zero(); // Torque on site b
753 Ea.zero(); // Electric field at site a
754 Eb.zero(); // Electric field at site b
755 dUdCa = 0.0; // fluctuating charge force at site a
756 dUdCb = 0.0; // fluctuating charge force at site a
757
758 // Indirect interactions mediated by the reaction field.
759 indirect_Pot = 0.0; // Potential
760 indirect_F.zero(); // Force
761 indirect_Ta.zero(); // Torque on site a
762 indirect_Tb.zero(); // Torque on site b
763
764 // Excluded potential that is still computed for fluctuating charges
765 excluded_Pot= 0.0;
766
767
768 // some variables we'll need independent of electrostatic type:
769
770 ri = 1.0 / *(idat.rij);
771 rhat = *(idat.d) * ri;
772
773 // logicals
774
775 a_is_Charge = data1.is_Charge;
776 a_is_Dipole = data1.is_Dipole;
777 a_is_Quadrupole = data1.is_Quadrupole;
778 a_is_Fluctuating = data1.is_Fluctuating;
779
780 b_is_Charge = data2.is_Charge;
781 b_is_Dipole = data2.is_Dipole;
782 b_is_Quadrupole = data2.is_Quadrupole;
783 b_is_Fluctuating = data2.is_Fluctuating;
784
785 // Obtain all of the required radial function values from the
786 // spline structures:
787
788 // needed for fields (and forces):
789 if (a_is_Charge || b_is_Charge) {
790 v01s->getValueAndDerivativeAt( *(idat.rij), v01, dv01);
791 }
792 if (a_is_Dipole || b_is_Dipole) {
793 v11s->getValueAndDerivativeAt( *(idat.rij), v11, dv11);
794 v11or = ri * v11;
795 }
796 if (a_is_Quadrupole || b_is_Quadrupole || (a_is_Dipole && b_is_Dipole)) {
797 v21s->getValueAndDerivativeAt( *(idat.rij), v21, dv21);
798 v22s->getValueAndDerivativeAt( *(idat.rij), v22, dv22);
799 v22or = ri * v22;
800 }
801
802 // needed for potentials (and forces and torques):
803 if ((a_is_Dipole && b_is_Quadrupole) ||
804 (b_is_Dipole && a_is_Quadrupole)) {
805 v31s->getValueAndDerivativeAt( *(idat.rij), v31, dv31);
806 v32s->getValueAndDerivativeAt( *(idat.rij), v32, dv32);
807 v31or = v31 * ri;
808 v32or = v32 * ri;
809 }
810 if (a_is_Quadrupole && b_is_Quadrupole) {
811 v41s->getValueAndDerivativeAt( *(idat.rij), v41, dv41);
812 v42s->getValueAndDerivativeAt( *(idat.rij), v42, dv42);
813 v43s->getValueAndDerivativeAt( *(idat.rij), v43, dv43);
814 v42or = v42 * ri;
815 v43or = v43 * ri;
816 }
817
818 // calculate the single-site contributions (fields, etc).
819
820 if (a_is_Charge) {
821 C_a = data1.fixedCharge;
822
823 if (a_is_Fluctuating) {
824 C_a += *(idat.flucQ1);
825 }
826
827 if (idat.excluded) {
828 *(idat.skippedCharge2) += C_a;
829 } else {
830 // only do the field if we're not excluded:
831 Eb -= C_a * pre11_ * dv01 * rhat;
832 }
833 }
834
835 if (a_is_Dipole) {
836 D_a = *(idat.dipole1);
837 rdDa = dot(rhat, D_a);
838 rxDa = cross(rhat, D_a);
839 if (!idat.excluded)
840 Eb -= pre12_ * ((dv11-v11or) * rdDa * rhat + v11or * D_a);
841 }
842
843 if (a_is_Quadrupole) {
844 Q_a = *(idat.quadrupole1);
845 trQa = Q_a.trace();
846 Qar = Q_a * rhat;
847 rQa = rhat * Q_a;
848 rdQar = dot(rhat, Qar);
849 rxQar = cross(rhat, Qar);
850 if (!idat.excluded)
851 Eb -= pre14_ * (trQa * rhat * dv21 + 2.0 * Qar * v22or
852 + rdQar * rhat * (dv22 - 2.0*v22or));
853 }
854
855 if (b_is_Charge) {
856 C_b = data2.fixedCharge;
857
858 if (b_is_Fluctuating)
859 C_b += *(idat.flucQ2);
860
861 if (idat.excluded) {
862 *(idat.skippedCharge1) += C_b;
863 } else {
864 // only do the field if we're not excluded:
865 Ea += C_b * pre11_ * dv01 * rhat;
866 }
867 }
868
869 if (b_is_Dipole) {
870 D_b = *(idat.dipole2);
871 rdDb = dot(rhat, D_b);
872 rxDb = cross(rhat, D_b);
873 if (!idat.excluded)
874 Ea += pre12_ * ((dv11-v11or) * rdDb * rhat + v11or * D_b);
875 }
876
877 if (b_is_Quadrupole) {
878 Q_b = *(idat.quadrupole2);
879 trQb = Q_b.trace();
880 Qbr = Q_b * rhat;
881 rQb = rhat * Q_b;
882 rdQbr = dot(rhat, Qbr);
883 rxQbr = cross(rhat, Qbr);
884 if (!idat.excluded)
885 Ea += pre14_ * (trQb * rhat * dv21 + 2.0 * Qbr * v22or
886 + rdQbr * rhat * (dv22 - 2.0*v22or));
887 }
888
889 if ((a_is_Fluctuating || b_is_Fluctuating) && idat.excluded) {
890 J = Jij[FQtids[idat.atid1]][FQtids[idat.atid2]];
891 }
892
893 if (a_is_Charge) {
894
895 if (b_is_Charge) {
896 pref = pre11_ * *(idat.electroMult);
897 U += C_a * C_b * pref * v01;
898 F += C_a * C_b * pref * dv01 * rhat;
899
900 // If this is an excluded pair, there are still indirect
901 // interactions via the reaction field we must worry about:
902
903 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
904 rfContrib = preRF_ * pref * C_a * C_b * *(idat.r2);
905 indirect_Pot += rfContrib;
906 indirect_F += rfContrib * 2.0 * ri * rhat;
907 }
908
909 // Fluctuating charge forces are handled via Coulomb integrals
910 // for excluded pairs (i.e. those connected via bonds) and
911 // with the standard charge-charge interaction otherwise.
912
913 if (idat.excluded) {
914 if (a_is_Fluctuating || b_is_Fluctuating) {
915 coulInt = J->getValueAt( *(idat.rij) );
916 if (a_is_Fluctuating) dUdCa += coulInt * C_b;
917 if (b_is_Fluctuating) dUdCb += coulInt * C_a;
918 excluded_Pot += C_a * C_b * coulInt;
919 }
920 } else {
921 if (a_is_Fluctuating) dUdCa += C_b * pref * v01;
922 if (a_is_Fluctuating) dUdCb += C_a * pref * v01;
923 }
924 }
925
926 if (b_is_Dipole) {
927 pref = pre12_ * *(idat.electroMult);
928 U += C_a * pref * v11 * rdDb;
929 F += C_a * pref * ((dv11 - v11or) * rdDb * rhat + v11or * D_b);
930 Tb += C_a * pref * v11 * rxDb;
931
932 if (a_is_Fluctuating) dUdCa += pref * v11 * rdDb;
933
934 // Even if we excluded this pair from direct interactions, we
935 // still have the reaction-field-mediated charge-dipole
936 // interaction:
937
938 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
939 rfContrib = C_a * pref * preRF_ * 2.0 * *(idat.rij);
940 indirect_Pot += rfContrib * rdDb;
941 indirect_F += rfContrib * D_b / (*idat.rij);
942 indirect_Tb += C_a * pref * preRF_ * rxDb;
943 }
944 }
945
946 if (b_is_Quadrupole) {
947 pref = pre14_ * *(idat.electroMult);
948 U += C_a * pref * (v21 * trQb + v22 * rdQbr);
949 F += C_a * pref * (trQb * dv21 * rhat + 2.0 * Qbr * v22or);
950 F += C_a * pref * rdQbr * rhat * (dv22 - 2.0*v22or);
951 Tb += C_a * pref * 2.0 * rxQbr * v22;
952
953 if (a_is_Fluctuating) dUdCa += pref * (v21 * trQb + v22 * rdQbr);
954 }
955 }
956
957 if (a_is_Dipole) {
958
959 if (b_is_Charge) {
960 pref = pre12_ * *(idat.electroMult);
961
962 U -= C_b * pref * v11 * rdDa;
963 F -= C_b * pref * ((dv11-v11or) * rdDa * rhat + v11or * D_a);
964 Ta -= C_b * pref * v11 * rxDa;
965
966 if (b_is_Fluctuating) dUdCb -= pref * v11 * rdDa;
967
968 // Even if we excluded this pair from direct interactions,
969 // we still have the reaction-field-mediated charge-dipole
970 // interaction:
971 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
972 rfContrib = C_b * pref * preRF_ * 2.0 * *(idat.rij);
973 indirect_Pot -= rfContrib * rdDa;
974 indirect_F -= rfContrib * D_a / (*idat.rij);
975 indirect_Ta -= C_b * pref * preRF_ * rxDa;
976 }
977 }
978
979 if (b_is_Dipole) {
980 pref = pre22_ * *(idat.electroMult);
981 DadDb = dot(D_a, D_b);
982 DaxDb = cross(D_a, D_b);
983
984 U -= pref * (DadDb * v21 + rdDa * rdDb * v22);
985 F -= pref * (dv21 * DadDb * rhat + v22or * (rdDb * D_a + rdDa * D_b));
986 F -= pref * (rdDa * rdDb) * (dv22 - 2.0*v22or) * rhat;
987 Ta += pref * ( v21 * DaxDb - v22 * rdDb * rxDa);
988 Tb += pref * (-v21 * DaxDb - v22 * rdDa * rxDb);
989
990 // Even if we excluded this pair from direct interactions, we
991 // still have the reaction-field-mediated dipole-dipole
992 // interaction:
993 if (summationMethod_ == esm_REACTION_FIELD && idat.excluded) {
994 rfContrib = -pref * preRF_ * 2.0;
995 indirect_Pot += rfContrib * DadDb;
996 indirect_Ta += rfContrib * DaxDb;
997 indirect_Tb -= rfContrib * DaxDb;
998 }
999 }
1000
1001 if (b_is_Quadrupole) {
1002 pref = pre24_ * *(idat.electroMult);
1003 DadQb = D_a * Q_b;
1004 DadQbr = dot(D_a, Qbr);
1005 DaxQbr = cross(D_a, Qbr);
1006
1007 U -= pref * ((trQb*rdDa + 2.0*DadQbr)*v31 + rdDa*rdQbr*v32);
1008 F -= pref * (trQb*D_a + 2.0*DadQb) * v31or;
1009 F -= pref * (trQb*rdDa + 2.0*DadQbr) * (dv31-v31or) * rhat;
1010 F -= pref * (D_a*rdQbr + 2.0*rdDa*rQb) * v32or;
1011 F -= pref * (rdDa * rdQbr * rhat * (dv32-3.0*v32or));
1012 Ta += pref * ((-trQb*rxDa + 2.0 * DaxQbr)*v31 - rxDa*rdQbr*v32);
1013 Tb += pref * ((2.0*cross(DadQb, rhat) - 2.0*DaxQbr)*v31
1014 - 2.0*rdDa*rxQbr*v32);
1015 }
1016 }
1017
1018 if (a_is_Quadrupole) {
1019 if (b_is_Charge) {
1020 pref = pre14_ * *(idat.electroMult);
1021 U += C_b * pref * (v21 * trQa + v22 * rdQar);
1022 F += C_b * pref * (trQa * rhat * dv21 + 2.0 * Qar * v22or);
1023 F += C_b * pref * rdQar * rhat * (dv22 - 2.0*v22or);
1024 Ta += C_b * pref * 2.0 * rxQar * v22;
1025
1026 if (b_is_Fluctuating) dUdCb += pref * (v21 * trQa + v22 * rdQar);
1027 }
1028 if (b_is_Dipole) {
1029 pref = pre24_ * *(idat.electroMult);
1030 DbdQa = D_b * Q_a;
1031 DbdQar = dot(D_b, Qar);
1032 DbxQar = cross(D_b, Qar);
1033
1034 U += pref * ((trQa*rdDb + 2.0*DbdQar)*v31 + rdDb*rdQar*v32);
1035 F += pref * (trQa*D_b + 2.0*DbdQa) * v31or;
1036 F += pref * (trQa*rdDb + 2.0*DbdQar) * (dv31-v31or) * rhat;
1037 F += pref * (D_b*rdQar + 2.0*rdDb*rQa) * v32or;
1038 F += pref * (rdDb * rdQar * rhat * (dv32-3.0*v32or));
1039 Ta += pref * ((-2.0*cross(DbdQa, rhat) + 2.0*DbxQar)*v31
1040 + 2.0*rdDb*rxQar*v32);
1041 Tb += pref * ((trQa*rxDb - 2.0 * DbxQar)*v31 + rxDb*rdQar*v32);
1042 }
1043 if (b_is_Quadrupole) {
1044 pref = pre44_ * *(idat.electroMult); // yes
1045 QaQb = Q_a * Q_b;
1046 trQaQb = QaQb.trace();
1047 rQaQb = rhat * QaQb;
1048 QaQbr = QaQb * rhat;
1049 QaxQb = cross(Q_a, Q_b);
1050 rQaQbr = dot(rQa, Qbr);
1051 rQaxQbr = cross(rQa, Qbr);
1052
1053 U += pref * (trQa * trQb + 2.0 * trQaQb) * v41;
1054 U += pref * (trQa * rdQbr + trQb * rdQar + 4.0 * rQaQbr) * v42;
1055 U += pref * (rdQar * rdQbr) * v43;
1056
1057 F += pref * rhat * (trQa * trQb + 2.0 * trQaQb)*dv41;
1058 F += pref*rhat*(trQa*rdQbr + trQb*rdQar + 4.0*rQaQbr)*(dv42-2.0*v42or);
1059 F += pref * rhat * (rdQar * rdQbr)*(dv43 - 4.0*v43or);
1060
1061 F += pref * 2.0 * (trQb*rQa + trQa*rQb) * v42or;
1062 F += pref * 4.0 * (rQaQb + QaQbr) * v42or;
1063 F += pref * 2.0 * (rQa*rdQbr + rdQar*rQb) * v43or;
1064
1065 Ta += pref * (- 4.0 * QaxQb * v41);
1066 Ta += pref * (- 2.0 * trQb * cross(rQa, rhat)
1067 + 4.0 * cross(rhat, QaQbr)
1068 - 4.0 * rQaxQbr) * v42;
1069 Ta += pref * 2.0 * cross(rhat,Qar) * rdQbr * v43;
1070
1071
1072 Tb += pref * (+ 4.0 * QaxQb * v41);
1073 Tb += pref * (- 2.0 * trQa * cross(rQb, rhat)
1074 - 4.0 * cross(rQaQb, rhat)
1075 + 4.0 * rQaxQbr) * v42;
1076 // Possible replacement for line 2 above:
1077 // + 4.0 * cross(rhat, QbQar)
1078
1079 Tb += pref * 2.0 * cross(rhat,Qbr) * rdQar * v43;
1080
1081 }
1082 }
1083
1084 if (idat.doElectricField) {
1085 *(idat.eField1) += Ea * *(idat.electroMult);
1086 *(idat.eField2) += Eb * *(idat.electroMult);
1087 }
1088
1089 if (a_is_Fluctuating) *(idat.dVdFQ1) += dUdCa * *(idat.sw);
1090 if (b_is_Fluctuating) *(idat.dVdFQ2) += dUdCb * *(idat.sw);
1091
1092 if (!idat.excluded) {
1093
1094 *(idat.vpair) += U;
1095 (*(idat.pot))[ELECTROSTATIC_FAMILY] += U * *(idat.sw);
1096 *(idat.f1) += F * *(idat.sw);
1097
1098 if (a_is_Dipole || a_is_Quadrupole)
1099 *(idat.t1) += Ta * *(idat.sw);
1100
1101 if (b_is_Dipole || b_is_Quadrupole)
1102 *(idat.t2) += Tb * *(idat.sw);
1103
1104 } else {
1105
1106 // only accumulate the forces and torques resulting from the
1107 // indirect reaction field terms.
1108
1109 *(idat.vpair) += indirect_Pot;
1110 (*(idat.excludedPot))[ELECTROSTATIC_FAMILY] += excluded_Pot;
1111 (*(idat.pot))[ELECTROSTATIC_FAMILY] += *(idat.sw) * indirect_Pot;
1112 *(idat.f1) += *(idat.sw) * indirect_F;
1113
1114 if (a_is_Dipole || a_is_Quadrupole)
1115 *(idat.t1) += *(idat.sw) * indirect_Ta;
1116
1117 if (b_is_Dipole || b_is_Quadrupole)
1118 *(idat.t2) += *(idat.sw) * indirect_Tb;
1119 }
1120 return;
1121 }
1122
1123 void Electrostatic::calcSelfCorrection(SelfData &sdat) {
1124
1125 if (!initialized_) initialize();
1126
1127 ElectrostaticAtomData data = ElectrostaticMap[Etids[sdat.atid]];
1128
1129 // logicals
1130 bool i_is_Charge = data.is_Charge;
1131 bool i_is_Dipole = data.is_Dipole;
1132 bool i_is_Quadrupole = data.is_Quadrupole;
1133 bool i_is_Fluctuating = data.is_Fluctuating;
1134 RealType C_a = data.fixedCharge;
1135 RealType self(0.0), preVal, DdD, trQ, trQQ;
1136
1137 if (i_is_Dipole) {
1138 DdD = data.dipole.lengthSquare();
1139 }
1140
1141 if (i_is_Fluctuating) {
1142 C_a += *(sdat.flucQ);
1143 // dVdFQ is really a force, so this is negative the derivative
1144 *(sdat.dVdFQ) -= *(sdat.flucQ) * data.hardness + data.electronegativity;
1145 (*(sdat.excludedPot))[ELECTROSTATIC_FAMILY] += (*sdat.flucQ) *
1146 (*(sdat.flucQ) * data.hardness * 0.5 + data.electronegativity);
1147 }
1148
1149 switch (summationMethod_) {
1150 case esm_REACTION_FIELD:
1151
1152 if (i_is_Charge) {
1153 // Self potential [see Wang and Hermans, "Reaction Field
1154 // Molecular Dynamics Simulation with Friedman’s Image Charge
1155 // Method," J. Phys. Chem. 99, 12001-12007 (1995).]
1156 preVal = pre11_ * preRF_ * C_a * C_a;
1157 (*(sdat.pot))[ELECTROSTATIC_FAMILY] -= 0.5 * preVal / cutoffRadius_;
1158 }
1159
1160 if (i_is_Dipole) {
1161 (*(sdat.pot))[ELECTROSTATIC_FAMILY] -= pre22_ * preRF_ * DdD;
1162 }
1163
1164 break;
1165
1166 case esm_SHIFTED_FORCE:
1167 case esm_SHIFTED_POTENTIAL:
1168 case esm_TAYLOR_SHIFTED:
1169 case esm_EWALD_FULL:
1170 if (i_is_Charge)
1171 self += selfMult1_ * pre11_ * C_a * (C_a + *(sdat.skippedCharge));
1172 if (i_is_Dipole)
1173 self += selfMult2_ * pre22_ * DdD;
1174 if (i_is_Quadrupole) {
1175 trQ = data.quadrupole.trace();
1176 trQQ = (data.quadrupole * data.quadrupole).trace();
1177 self += selfMult4_ * pre44_ * (2.0*trQQ + trQ*trQ);
1178 if (i_is_Charge)
1179 self -= selfMult2_ * pre14_ * 2.0 * C_a * trQ;
1180 }
1181 (*(sdat.pot))[ELECTROSTATIC_FAMILY] += self;
1182 break;
1183 default:
1184 break;
1185 }
1186 }
1187
1188 RealType Electrostatic::getSuggestedCutoffRadius(pair<AtomType*, AtomType*> atypes) {
1189 // This seems to work moderately well as a default. There's no
1190 // inherent scale for 1/r interactions that we can standardize.
1191 // 12 angstroms seems to be a reasonably good guess for most
1192 // cases.
1193 return 12.0;
1194 }
1195
1196
1197 void Electrostatic::ReciprocalSpaceSum(potVec& pot) {
1198
1199 RealType kPot = 0.0;
1200 RealType kVir = 0.0;
1201
1202 const RealType mPoleConverter = 0.20819434; // converts from the
1203 // internal units of
1204 // Debye (for dipoles)
1205 // or Debye-angstroms
1206 // (for quadrupoles) to
1207 // electron angstroms or
1208 // electron-angstroms^2
1209
1210 const RealType eConverter = 332.0637778; // convert the
1211 // Charge-Charge
1212 // electrostatic
1213 // interactions into kcal /
1214 // mol assuming distances
1215 // are measured in
1216 // angstroms.
1217
1218 Mat3x3d hmat = info_->getSnapshotManager()->getCurrentSnapshot()->getHmat();
1219 Vector3d box = hmat.diagonals();
1220 RealType boxMax = box.max();
1221
1222 //int kMax = int(2.0 * M_PI / (pow(dampingAlpha_,2)*cutoffRadius_ * boxMax) );
1223 int kMax = 7;
1224 int kSqMax = kMax*kMax + 2;
1225
1226 int kLimit = kMax+1;
1227 int kLim2 = 2*kMax+1;
1228 int kSqLim = kSqMax;
1229
1230 vector<RealType> AK(kSqLim+1, 0.0);
1231 RealType xcl = 2.0 * M_PI / box.x();
1232 RealType ycl = 2.0 * M_PI / box.y();
1233 RealType zcl = 2.0 * M_PI / box.z();
1234 RealType rcl = 2.0 * M_PI / boxMax;
1235 RealType rvol = 2.0 * M_PI /(box.x() * box.y() * box.z());
1236
1237 if(dampingAlpha_ < 1.0e-12) return;
1238
1239 RealType ralph = -0.25/pow(dampingAlpha_,2);
1240
1241 // Calculate and store exponential factors
1242
1243 vector<vector<Vector3d> > eCos;
1244 vector<vector<Vector3d> > eSin;
1245
1246 int nMax = info_->getNAtoms();
1247
1248 eCos.resize(kLimit+1);
1249 eSin.resize(kLimit+1);
1250 for (int j = 0; j < kLimit+1; j++) {
1251 eCos[j].resize(nMax);
1252 eSin[j].resize(nMax);
1253 }
1254
1255 Vector3d t( 2.0 * M_PI );
1256 t.Vdiv(t, box);
1257
1258
1259 SimInfo::MoleculeIterator mi;
1260 Molecule::AtomIterator ai;
1261 int i;
1262 Vector3d r;
1263 Vector3d tt;
1264 Vector3d w;
1265 Vector3d u;
1266 Vector3d a;
1267 Vector3d b;
1268
1269 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1270 mol = info_->nextMolecule(mi)) {
1271 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1272 atom = mol->nextAtom(ai)) {
1273
1274 i = atom->getLocalIndex();
1275 r = atom->getPos();
1276 info_->getSnapshotManager()->getCurrentSnapshot()->wrapVector(r);
1277
1278 tt.Vmul(t, r);
1279
1280
1281 eCos[1][i] = Vector3d(1.0, 1.0, 1.0);
1282 eSin[1][i] = Vector3d(0.0, 0.0, 0.0);
1283 eCos[2][i] = Vector3d(cos(tt.x()), cos(tt.y()), cos(tt.z()));
1284 eSin[2][i] = Vector3d(sin(tt.x()), sin(tt.y()), sin(tt.z()));
1285
1286 u = eCos[2][i];
1287 w = eSin[2][i];
1288
1289 for(int l = 3; l <= kLimit; l++) {
1290 eCos[l][i].x() = eCos[l-1][i].x()*eCos[2][i].x() - eSin[l-1][i].x()*eSin[2][i].x();
1291 eCos[l][i].y() = eCos[l-1][i].y()*eCos[2][i].y() - eSin[l-1][i].y()*eSin[2][i].y();
1292 eCos[l][i].z() = eCos[l-1][i].z()*eCos[2][i].z() - eSin[l-1][i].z()*eSin[2][i].z();
1293
1294 eSin[l][i].x() = eSin[l-1][i].x()*eCos[2][i].x() + eCos[l-1][i].x()*eSin[2][i].x();
1295 eSin[l][i].y() = eSin[l-1][i].y()*eCos[2][i].y() + eCos[l-1][i].y()*eSin[2][i].z();
1296 eSin[l][i].z() = eSin[l-1][i].z()*eCos[2][i].z() + eCos[l-1][i].z()*eSin[2][i].y();
1297
1298
1299 // a.Vmul(eCos[l-1][i], u);
1300 // b.Vmul(eSin[l-1][i], w);
1301 // eCos[l][i] = a - b;
1302 // a.Vmul(eSin[l-1][i], u);
1303 // b.Vmul(eCos[l-1][i], w);
1304 // eSin[l][i] = a + b;
1305
1306 }
1307 }
1308 }
1309
1310 // Calculate and store AK coefficients:
1311
1312 RealType eksq = 1.0;
1313 RealType expf = 0.0;
1314 if (ralph < 0.0) expf = exp(ralph*rcl*rcl);
1315 for (i = 1; i <= kSqLim; i++) {
1316 RealType rksq = float(i)*rcl*rcl;
1317 eksq = expf*eksq;
1318 AK[i] = eConverter * eksq/rksq;
1319 }
1320
1321 /*
1322 * Loop over all k vectors k = 2 pi (ll/Lx, mm/Ly, nn/Lz)
1323 * the values of ll, mm and nn are selected so that the symmetry of
1324 * reciprocal lattice is taken into account i.e. the following
1325 * rules apply.
1326 *
1327 * ll ranges over the values 0 to kMax only.
1328 *
1329 * mm ranges over 0 to kMax when ll=0 and over
1330 * -kMax to kMax otherwise.
1331 * nn ranges over 1 to kMax when ll=mm=0 and over
1332 * -kMax to kMax otherwise.
1333 *
1334 * Hence the result of the summation must be doubled at the end.
1335 */
1336
1337 std::vector<RealType> clm(nMax, 0.0);
1338 std::vector<RealType> slm(nMax, 0.0);
1339 std::vector<RealType> ckr(nMax, 0.0);
1340 std::vector<RealType> skr(nMax, 0.0);
1341 std::vector<RealType> ckc(nMax, 0.0);
1342 std::vector<RealType> cks(nMax, 0.0);
1343 std::vector<RealType> dkc(nMax, 0.0);
1344 std::vector<RealType> dks(nMax, 0.0);
1345 std::vector<RealType> qkc(nMax, 0.0);
1346 std::vector<RealType> qks(nMax, 0.0);
1347 std::vector<Vector3d> dxk(nMax, V3Zero);
1348 std::vector<Vector3d> qxk(nMax, V3Zero);
1349
1350 int mMin = kLimit;
1351 int nMin = kLimit + 1;
1352 for (int l = 1; l <= kLimit; l++) {
1353 int ll = l - 1;
1354 RealType rl = xcl * float(ll);
1355 for (int mmm = mMin; mmm <= kLim2; mmm++) {
1356 int mm = mmm - kLimit;
1357 int m = abs(mm) + 1;
1358 RealType rm = ycl * float(mm);
1359 // Set temporary products of exponential terms
1360 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1361 mol = info_->nextMolecule(mi)) {
1362 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1363 atom = mol->nextAtom(ai)) {
1364
1365 i = atom->getLocalIndex();
1366 if(mm < 0) {
1367 clm[i] = eCos[l][i].x()*eCos[m][i].y()
1368 + eSin[l][i].x()*eSin[m][i].y();
1369 slm[i] = eSin[l][i].x()*eCos[m][i].y()
1370 - eSin[m][i].y()*eCos[l][i].x();
1371 } else {
1372 clm[i] = eCos[l][i].x()*eCos[m][i].y()
1373 - eSin[l][i].x()*eSin[m][i].y();
1374 slm[i] = eSin[l][i].x()*eCos[m][i].y()
1375 + eSin[m][i].y()*eCos[l][i].x();
1376 }
1377 }
1378 }
1379 for (int nnn = nMin; nnn <= kLim2; nnn++) {
1380 int nn = nnn - kLimit;
1381 int n = abs(nn) + 1;
1382 RealType rn = zcl * float(nn);
1383 // Test on magnitude of k vector:
1384 int kk=ll*ll + mm*mm + nn*nn;
1385 if(kk <= kSqLim) {
1386 Vector3d kVec = Vector3d(rl, rm, rn);
1387 Mat3x3d k2 = outProduct(kVec, kVec);
1388 // Calculate exp(ikr) terms
1389 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1390 mol = info_->nextMolecule(mi)) {
1391 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1392 atom = mol->nextAtom(ai)) {
1393 i = atom->getLocalIndex();
1394
1395 if (nn < 0) {
1396 ckr[i]=clm[i]*eCos[n][i].z()+slm[i]*eSin[n][i].z();
1397 skr[i]=slm[i]*eCos[n][i].z()-clm[i]*eSin[n][i].z();
1398 } else {
1399 ckr[i]=clm[i]*eCos[n][i].z()-slm[i]*eSin[n][i].z();
1400 skr[i]=slm[i]*eCos[n][i].z()+clm[i]*eSin[n][i].z();
1401 }
1402 }
1403 }
1404
1405 // Calculate scalar and vector products for each site:
1406
1407 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1408 mol = info_->nextMolecule(mi)) {
1409 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1410 atom = mol->nextAtom(ai)) {
1411 i = atom->getLocalIndex();
1412 int atid = atom->getAtomType()->getIdent();
1413 ElectrostaticAtomData data = ElectrostaticMap[Etids[atid]];
1414
1415 if (data.is_Charge) {
1416 RealType C = data.fixedCharge;
1417 if (atom->isFluctuatingCharge()) C += atom->getFlucQPos();
1418 ckc[i] = C * ckr[i];
1419 cks[i] = C * skr[i];
1420 }
1421
1422 if (data.is_Dipole) {
1423 Vector3d D = atom->getDipole() * mPoleConverter;
1424 RealType dk = dot(kVec, D);
1425 dxk[i] = cross(kVec, D);
1426 dkc[i] = dk * ckr[i];
1427 dks[i] = dk * skr[i];
1428 }
1429 if (data.is_Quadrupole) {
1430 Mat3x3d Q = atom->getQuadrupole();
1431 Q *= mPoleConverter;
1432 RealType qk = -( Q * k2 ).trace();
1433 qxk[i] = -2.0 * cross(k2, Q);
1434 qkc[i] = qk * ckr[i];
1435 qks[i] = qk * skr[i];
1436 }
1437 }
1438 }
1439
1440 // calculate vector sums
1441
1442 RealType ckcs = std::accumulate(ckc.begin(),ckc.end(),0.0);
1443 RealType ckss = std::accumulate(cks.begin(),cks.end(),0.0);
1444 RealType dkcs = std::accumulate(dkc.begin(),dkc.end(),0.0);
1445 RealType dkss = std::accumulate(dks.begin(),dks.end(),0.0);
1446 RealType qkcs = std::accumulate(qkc.begin(),qkc.end(),0.0);
1447 RealType qkss = std::accumulate(qks.begin(),qks.end(),0.0);
1448
1449
1450 #ifdef IS_MPI
1451 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &ckcs, 1, MPI::REALTYPE,
1452 MPI::SUM);
1453 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &ckss, 1, MPI::REALTYPE,
1454 MPI::SUM);
1455 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &dkcs, 1, MPI::REALTYPE,
1456 MPI::SUM);
1457 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &dkss, 1, MPI::REALTYPE,
1458 MPI::SUM);
1459 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &qkcs, 1, MPI::REALTYPE,
1460 MPI::SUM);
1461 MPI::COMM_WORLD.Allreduce(MPI::IN_PLACE, &qkss, 1, MPI::REALTYPE,
1462 MPI::SUM);
1463 #endif
1464
1465 // Accumulate potential energy and virial contribution:
1466
1467 kPot += 2.0 * rvol * AK[kk]*((ckss+dkcs-qkss)*(ckss+dkcs-qkss)
1468 + (ckcs-dkss-qkcs)*(ckcs-dkss-qkss));
1469
1470 kVir -= 2.0 * rvol * AK[kk]*(ckcs*ckcs+ckss*ckss
1471 +4.0*(ckss*dkcs-ckcs*dkss)
1472 +3.0*(dkcs*dkcs+dkss*dkss)
1473 -6.0*(ckss*qkss+ckcs*qkcs)
1474 +8.0*(dkss*qkcs-dkcs*qkss)
1475 +5.0*(qkss*qkss+qkcs*qkcs));
1476
1477 // Calculate force and torque for each site:
1478
1479 for (Molecule* mol = info_->beginMolecule(mi); mol != NULL;
1480 mol = info_->nextMolecule(mi)) {
1481 for(Atom* atom = mol->beginAtom(ai); atom != NULL;
1482 atom = mol->nextAtom(ai)) {
1483
1484 i = atom->getLocalIndex();
1485 int atid = atom->getAtomType()->getIdent();
1486 ElectrostaticAtomData data = ElectrostaticMap[Etids[atid]];
1487
1488 RealType qfrc = AK[kk]*((cks[i]+dkc[i]-qks[i])*(ckcs-dkss-qkcs)
1489 - (ckc[i]-dks[i]-qkc[i])*(ckss+dkcs-qkss));
1490 RealType qtrq1 = AK[kk]*(skr[i]*(ckcs-dkss-qkcs)
1491 -ckr[i]*(ckss+dkcs-qkss));
1492 RealType qtrq2 = 2.0*AK[kk]*(ckr[i]*(ckcs-dkss-qkcs)+
1493 skr[i]*(ckss+dkcs-qkss));
1494
1495 atom->addFrc( 4.0 * rvol * qfrc * kVec );
1496
1497 if (data.is_Dipole) {
1498 atom->addTrq( 4.0 * rvol * qtrq1 * dxk[i] );
1499 }
1500 if (data.is_Quadrupole) {
1501 atom->addTrq( 4.0 * rvol * qtrq2 * qxk[i] );
1502 }
1503 }
1504 }
1505 }
1506 }
1507 nMin = 1;
1508 }
1509 mMin = 1;
1510 }
1511 cerr << "kPot = " << kPot << "\n";
1512 pot[ELECTROSTATIC_FAMILY] += kPot;
1513 }
1514 }

Properties

Name Value
svn:eol-style native