| 1 |
// This is the forcefield file for the Dipolar Unified-atom Force Field (DUFF) |
| 2 |
// |
| 3 |
// The sections are divided into AtomTypes |
| 4 |
// |
| 5 |
// many parameters (but not all) are derived from the TRAPPE force field |
| 6 |
// of Siepmann's group. |
| 7 |
|
| 8 |
begin BaseAtomTypes |
| 9 |
//Name mass (amu) |
| 10 |
O 15.9994 |
| 11 |
H 1.0079 |
| 12 |
M 0.0 |
| 13 |
end BaseAtomTypes |
| 14 |
|
| 15 |
begin AtomTypes |
| 16 |
//Name mass (amu) |
| 17 |
O_TIP4P_FQ O |
| 18 |
H_TIP4P_FQ H |
| 19 |
M_TIP4P_FQ M |
| 20 |
end AtomTypes |
| 21 |
|
| 22 |
begin LennardJonesAtomTypes |
| 23 |
//Name epsilon sigma |
| 24 |
O_TIP4P_FQ 0.2862 3.159 |
| 25 |
end LennardJonesAtomTypes |
| 26 |
|
| 27 |
begin ChargeAtomTypes |
| 28 |
// Name charge |
| 29 |
//O_TIP4P_FQ 0.0 |
| 30 |
//H_TIP4P_FQ 0.0 |
| 31 |
//M_TIP4P_FQ 0.0 |
| 32 |
end ChargeAtomTypes |
| 33 |
|
| 34 |
|
| 35 |
begin FluctuatingChargeAtomTypes |
| 36 |
//Name chi (kcal/mol e) hardness (kcal/(mol*e^2)) slaterN slaterZeta ChargeMass (fs^2 kcal/ e^2 mol) |
| 37 |
//Values obtained from Rick, Stuart, and Berne J Chem Phys, 1994, 101 |
| 38 |
//Since they gave chi as an electronegativity difference, we will assign Oxygen's (the M site |
| 39 |
//actually for TIP4P) electronegativity from Rappe and Goddard III, and setting H to equal |
| 40 |
//the difference |
| 41 |
// Rappe and Goddard, O or M chi: 8.741 eV = 201.5705 kcal/mol |
| 42 |
// Rick, Stuart, and Berne, delta Chi between O and H = 68.49 |
| 43 |
// SlaterZeta has units of Bohr radius |
| 44 |
// Fictitious ChargeMass has units of (fs / e)^2 kcal / mol (note the ps->fs difference between |
| 45 |
// this code and the Rick, Stuart, and Berne paper |
| 46 |
H_TIP4P_FQ 133.0805 353.0 1 0.90 60.0 |
| 47 |
M_TIP4P_FQ 201.5705 371.6 2 1.63 60.0 |
| 48 |
end FluctuatingChargeAtomTypes |
