MacroModel Reference Manual - ISP

Chapter 4: Operation CodesThis command is intended to reject unwanted cis or trans isomers created during a conformationsearch. Appropriate values for rejecting all trans isomers of a cis torsion (original torsionangle ~0) are arg5=0 and arg6=90. To reject all cis isomers of a trans torsion (original torsionangle ~180), use arg5=90, and arg6=180.Note:arg1-4arg5arg6Torsion checks do not limit the range of conformers searched or constrain the torsionduring minimization. See FXTA on page 71 for details on applying a torsionalconstraint during minimization.Atom numbers specifying a dihedral angleMinimum allowable angle (|degrees|)Maximum allowable angle (|degrees|)MCMF — Monte Carlo Maximum constraint FailuresThis command allows you to adjust the maximum number of constraint failures, e.g. ringclosures (RCA4) or constrained torsion (TORC), that are allowed before accepting a faultystructure. A limit of some kind is appropriate since the user could supply constraints that makevalid structure generation impossible. Thus the program tries a given starting geometry and agiven number of varying torsions (or other coordinates) repeatedly until arg1 failures (or thedefault of 10000) have occurred. Then, the program allows a different number of varyingtorsions and makes arg1 new attempts to create a valid structure. This process is repeated arg2times before a faulty structure is accepted. Thus when constraint tests have failed arg1 times,the program allows arg2 failures (of arg1 tries each) before accepting the structure anyway.Such faulty structures often fail to minimize properly.arg1Maximum number of constraint failures with constant torsion set (default:10000)arg2 Maximum number of attempts with variable torsion sets (default: 10)SMPL — monte carlo SaMPLingThis command allows one to write sample structures to disk during a Monte Carlo SingleMinimum (MCSM) run.arg1Sampling interval0 Write the last structure sampled and the global minimum; the latter appears last inthe output file.116MacroModel 9.7 Reference Manual