AFMM: A molecular mechanics force field vibrational parametrization program

Abstract

AFMM (Automated Frequency Matching Method) is a program package for molecular mechanics force field parametrization. The method used fits the molecular mechanics potential function to both vibrational frequencies and eigenvector projections derived from quantum chemical calculations. The program optimizes an initial parameter set (either pre-existing or using chemically-reasonable estimation) by iteratively changing them until the optimal fit with the reference set is obtained. By implementing a Monte Carlo-like algorithm to vary the parameters, the tedious task of manual parametrization is replaced by an efficient automated procedure. The program is best suited for optimization of small rigid molecules in a well-defined energy minimum, for which the harmonic approximation to the energy surface is appropriate for describing the intra-molecular degrees of freedom. Program summary Title of program: AFMM Catalogue identifier: ADUZ Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADUZ Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: x86 PC, SGI, Sun Microsystems Operating system: GNU/Linux, BSD, IRIX, Solaris Programming language used: Python Memory required: 10 Mbytes No. of bits in a word: 32 or 64 No. of processors used: 1 Parallelized?: No No. of lines in distributed program, including test data, etc.:13 127 No. of bytes in distributed program, including test data, etc.: 182 550 Distribution format: tar.gz Typical running time: 24 h Nature of the physical problem: Molecular mechanics force field parametrization. Method of solution:Fitting of the molecular mechanics potential to normal modes derived from quantum chemical calculations. The missing force field parameters are optimized via a merit function to obtain the optimal fit with the reference quantum mechanical set.