--- branches/development/src/nonbonded/LJ.cpp	2011/01/05 14:49:05	1536
+++ branches/development/src/nonbonded/LJ.cpp	2011/11/22 20:38:56	1665
@@ -36,7 +36,8 @@
  * [1]  Meineke, et al., J. Comp. Chem. 26, 252-271 (2005).             
  * [2]  Fennell & Gezelter, J. Chem. Phys. 124, 234104 (2006).          
  * [3]  Sun, Lin & Gezelter, J. Chem. Phys. 128, 24107 (2008).          
- * [4]  Vardeman & Gezelter, in progress (2009).                        
+ * [4]  Kuang & Gezelter,  J. Chem. Phys. 133, 164101 (2010).
+ * [5]  Vardeman, Stocker & Gezelter, J. Chem. Theory Comput. 7, 834 (2011).
  */
 
 #include <stdio.h>
@@ -48,8 +49,7 @@ namespace OpenMD {
 
 namespace OpenMD {
 
-  LJ::LJ() : name_("LJ"), initialized_(false), shiftedPot_(false), 
-             shiftedFrc_(false), forceField_(NULL) {}
+  LJ::LJ() : name_("LJ"), initialized_(false), forceField_(NULL) {}
 
   LJParam LJ::getLJParam(AtomType* atomType) {
     
@@ -243,10 +243,9 @@ namespace OpenMD {
   void LJ::calcForce(InteractionData &idat) {
     
     if (!initialized_) initialize();
-    
-    pair<AtomType*, AtomType*> key = make_pair(idat.atype1, idat.atype2);
+
     map<pair<AtomType*, AtomType*>, LJInteractionData>::iterator it;
-    it = MixingMap.find(key);
+    it = MixingMap.find( idat.atypes );
     
     if (it != MixingMap.end())  {
       
@@ -262,31 +261,31 @@ namespace OpenMD {
       RealType myDeriv = 0.0;
       RealType myDerivC = 0.0;
      
-      ros = idat.rij * sigmai;
+      ros = *(idat.rij) * sigmai;     
       
       getLJfunc(ros, myPot, myDeriv);
       
-      if (shiftedPot_) {
-        rcos = idat.rcut * sigmai;
+      if (idat.shiftedPot) {
+        rcos = *(idat.rcut) * sigmai;
         getLJfunc(rcos, myPotC, myDerivC);
         myDerivC = 0.0;
-      } else if (LJ::shiftedFrc_) {
-        rcos = idat.rcut * sigmai;
+      } else if (idat.shiftedForce) {
+        rcos = *(idat.rcut) * sigmai;
         getLJfunc(rcos, myPotC, myDerivC);
-        myPotC = myPotC + myDerivC * (idat.rij - idat.rcut) * sigmai;
+        myPotC = myPotC + myDerivC * (*(idat.rij) - *(idat.rcut)) * sigmai;
       } else {
         myPotC = 0.0;
         myDerivC = 0.0;        
       }
 
-      RealType pot_temp = idat.vdwMult * epsilon * (myPot - myPotC);
-      idat.vpair[0] += pot_temp;
+      RealType pot_temp = *(idat.vdwMult) * epsilon * (myPot - myPotC);
+      *(idat.vpair) += pot_temp;
       
-      RealType dudr = idat.sw * idat.vdwMult * epsilon * (myDeriv - 
-                                                          myDerivC)*sigmai;
-      
-      idat.pot[0] += idat.sw * pot_temp;
-      idat.f1 = idat.d * dudr / idat.rij;      
+      RealType dudr = *(idat.sw) * *(idat.vdwMult) * epsilon * (myDeriv - 
+                                                                myDerivC)*sigmai;      
+
+      (*(idat.pot))[VANDERWAALS_FAMILY] += *(idat.sw) * pot_temp;
+      *(idat.f1) += *(idat.d) * dudr / *(idat.rij);
     }
     return;
   }
@@ -306,11 +305,10 @@ namespace OpenMD {
     return;
   }
   
-  RealType LJ::getSuggestedCutoffRadius(AtomType* at1, AtomType* at2) {
+  RealType LJ::getSuggestedCutoffRadius(pair<AtomType*, AtomType*> atypes) {
     if (!initialized_) initialize();   
-    pair<AtomType*, AtomType*> key = make_pair(at1, at2); 
     map<pair<AtomType*, AtomType*>, LJInteractionData>::iterator it;
-    it = MixingMap.find(key);
+    it = MixingMap.find(atypes);
     if (it == MixingMap.end()) 
       return 0.0;
     else  {