MacroModel Reference Manual - ISP

Chapter 4: Operation CodesMaximization is accomplished by taking a short FMNR step in the local coordinate systemdefined by the eigenvectors of the new Hessian, but following the selected eigenvector in thereverse (uphill) direction. This procedure is continued, iteratively, always following the ravineeigenvector uphill while following the remaining eigenvalues in their normal directions, untilconvergence to a saddle point is achieved. SDLP can follow multiple modes, and each mode isfollowed in both directions. DEBG 94 saves all the intermediate structures in the output structurefile and colors each mode-following sequence differently for better visualization.This command is allowed only if a MINI has been performed, unless DEBG 211 has been set.arg1First mode to follow0 Default: 1 (i.e., the eigenvector of lowest frequency).n>0 Start with the nth eigenvector.arg2Last mode to follow0 Default: 1 (i.e., only follow a single mode).n>0 Follow n modes.arg3Maximum steps0 Default: 50 steps.>0 Maximum steps for saddle point search.arg5Maximum energy increase0 Default: 100 kJ/mol.>0 Maximum energy increase [kJ/mol] above the starting energy minimum allowedduring saddle point search. The search is aborted if this limit is exceeded.arg6Maximum coordinate movementMaximum allowable change in any coordinate of the moving atoms. If the “natural”FMNR move would exceed this value, we would instead travel along the specifieddirection (eigenvector) only far enough to achieve this value.0 Default: 0.1 Å.>0 Maximum allowed motion in Å.62MacroModel 9.7 Reference Manual