MacroModel Reference Manual - ISP

Chapter 5: MINTAMNTA — Mode iNTegrAtionarg1Number of MINTA iterationsThe MINTA numerical integrals are calculated in statistical blocks to achieve betterconvergence. The number of blocks used is referred to as the number of MINTAiterations.5 (Default).n n > 0 (It is not recommended to use values n > 10).arg2Number of energy evaluations per MINTA iterationMINTA integration is based on single point energy evaluations. The total number ofenergy evaluations per structure is equal to arg1 × arg2.0 2000 (default).n n > 0 (It is not recommended to use values n > 10,000).arg3Flag to choose adaptive MINTA integrationAdaptive MINTA integration is slightly more accurate than the default, non-adaptiveintegration mode. Note however, that using adaptive MINTA is expected to bebeneficial only if arg4 is in the range of 1-10.0 Non-adaptive MINTA (default).n n ≠ 0 selects adaptive MINTA (only recommended when 1 ≤ |arg4| ≤ 10).arg4Number of “soft” degrees of freedom, for which numerical MINTA integrationis appliedMINTA integration is carried out in normal mode space. Although MINTA can beinstructed to utilize numerical integration in all degrees of freedom, it is far moreefficient to partition the degrees of freedom into two categories, “soft” and “hard,”corresponding to low-frequency and high-frequency vibrational modes, respectively.The partition is somewhat arbitrary, of course, but generally “hard” modescan be integrated with high accuracy using an extremely fast analytical approximationto the MINTA integral. “Soft” modes, however, have to be integratednumerically to account for significant anharmonic effects. Therefore, a typicalMINTA calculation involves numerical integration in “soft-mode” space and analyticalintegration in “hard-mode” space.170MacroModel 9.7 Reference Manual