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275. MODFOR: Normal Coordinate Analysis Solution by a
Systematic Variation in the Wilson F-Matrix
by L. D. Buelow and E. A. Dorko, Department of Aero- Mechanical Engineering, Air Force Institute of Technology, Wright-Patterson Air Force Base, Dayton, Ohio 45433 The MODFOR program computes the fundamental frequencies of vibration using the Wilson FG matrix method for molecules whose force constants are unknown. Known force constants from molecules with similar structure and bond configuration are used as the initial input. The program then varies a designated subset of force constants in the Wilson F matrix by an incremental percentage and calculates the fundamental frequencies resulting from the altered matrix. A matrix subset is defined as the diagonal force constant corresponding to a particular vibrational mode and all interaction force constants involving that mode (i.e., i,j = 1,2...n). The theory for MODFOR is fully described in E. A. Dorko and L. D. Buelow, "Vapor Phase Infrared Spectrum of Nitrosyl Cyanide," J. Chem. Phys. (1975). The theory for the subroutines is given in B. T. Smith, J. M. Boyle and B. S. Garbow, Matrix Eigen System Routines- Eispack Guide: Lecture Notes in Computer Science VI (New York: Springer-Verlag), 1974. FORTRAN IV (CDC 6600) Lines of Code: 457 Recommended Citation: L. D. Buelow and E. A. Dorko, QCPE 11, 275 (1975). |