The FIELD File

The FIELD file contains the force field information defining the nature of the molecular forces. It is read by the subroutine SYSDEF. Excerpts from a force field file are shown below. The example is the antibiotic Valinomycin in a cluster of 146 water molecules.

Valinomycin Molecule with 146 SPC Waters
UNITS kcal

MOLECULES    2
Valinomycin
NUMMOLS 1
ATOMS 168
    O        16.0000     -0.4160    1
    OS       16.0000     -0.4550    1
    "          "           "        "
    "          "           "        "
    HC        1.0080      0.0580    1
    C        12.0100      0.4770    1
BONDS 78
harm   31   19 674.000     1.44900
harm   33   31 620.000     1.52600
    "    "    "    "         "
    "    "    "    "         "
harm  168   19 980.000     1.33500
harm  168  162 634.000     1.52200
CONSTRAINTS 90
   20   19    1.000017
   22   21    1.000032
    "    "     " 
    "    "     " 
  166  164    1.000087
  167  164    0.999968
ANGLES 312
harm   43    2   44  200.00      116.40
harm   69    5   70  200.00      116.40
  "    "    "    "     "           "
  "    "    "    "     "           "
harm   18  168  162  160.00      120.40
harm   19  168  162  140.00      116.60
DIHEDRALS 371
harm    1   43    2   44  2.3000      180.00
harm   31   43    2   44  2.3000      180.00
  "    "    "    "    "     "           "
  "    "    "    "    "     "           "
cos   149   17  161   16  10.500      180.00
cos   162   19  168   18  10.500      180.00
FINISH
SPC Water
NUMMOLS 146
ATOMS  3
    OW       16.0000     -0.8200
    HW        1.0080      0.4100
    HW        1.0080      0.4100
CONSTRAINTS  3
    1    2    1.0000
    1    3    1.0000
    2    3    1.63299
FINISH
VDW   45
C       C         lj   0.12000      3.2963
C       CT        lj   0.08485      3.2518
"       "         "     "            " 
"       "         "     "            " 
"       "         "     "            " 
OW      OS        lj   0.15100      3.0451
OS      OS        lj   0.15000      2.9400
CLOSE