MacroModel Reference Manual - ISP

Appendix D: Force-Field File FormatCAll rights reservedCC Energy Functions and Conversion Factors in UseC ------ --------- --- ---------- ------- -- ----10 STR 2 601.993920 BND 2 601.993920 S-B 1 601.993920 TOR 1 2.092000 IMP 1 60.199390 VDW 4 4.184000 ELE 1 1389.500000 HBD 1 418.400000 V14 4 1.000000 FIX 1 4.184000 BCI 2 1.000000 FCH 2 1.000000 SEL 1 O Original MM2 Parameters0 SEL 1 M Modified MM2 Parameters0 SEL 1 A Added parameters0 SEL 2 1 High quality parameters0 SEL 2 2 Tentative value parameters0 SEL 2 3 Low quality parameters0 ALT 1 a MM2 hydrocarbon params0 ALT 2 b Kroon-Battenburg Lp params0 ALT 3 L Z0 is lithiumD.2.1Equation SpecificationThe section extending from the STR to the FCH line above tells the program which equations touse for the various types of interaction and give factors which convert from published forcefield units to kJ/mol. These data are encoded in lines beginning with I=0. Later, in the MainParameter and Substructure sections, parameters are specified in whatever units were used inthe original publications.In general, each force-field equation has certain universal constants which do not vary with theatom types in the interaction. It is possible to specify these on the equation-specification line;however, this facility is now used only for BMFF force fields.Note: The van der Waals factors may be modified when the separation between atoms is nearthe cutoff.Stretch0 None1 Symmetric (Hooke’s law) stretchMacroModel 9.7 Reference Manual 191