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570. ENERO: Algorithm to Calculate Shortest Distances
between Rods Modelling Linear Molecules
by S. Lago and P. Sevilla, Departamento de Química Física, Facultad de Químicas, Universidad Complutense, 28040 Madrid, España ENERO is an efficient algorithm to calculate shortest distances between rods modelling linear molecules. Orientational averages of shortest distance, intermolecular potential and Boltzmann factor are calculated. This algorithm is based on division of the segment (considered as a closed set) into an open set + extremum points. Subsequent projection of the open set is over the entire real line; and the use of Lagrange's multipliers is made to calculate the shortest distance between open sets. Standard geometrical formulae are used to calculate distances between extrema and between extrema and segments. The shortest distance between closed sets is the least of these three kinds of distances. Required input parameters are: 1. Number of the output device (LW), number of orientations used in the averages (NR.ORIENTATIONS) and number of distances between geometrical centers (GC), where the average should be calculated (NR. GC- GC DISTANCES). 2. A test number for the grid of the orientation angles (DELTAA). Any even number is allowable, and the exact value is irrelevant. Moreover, the grid is constructed from successive GC-GC distances (DELTAR). 3. Zero of the intermolecular potential (SIGMA), well depth (EPSIL), length of the rod (LENGTH) and the temperature (TEMP) at which the Boltzmann factor should be calculated. Potential parameters refer to the Kihara potential; the potential used in the test is the reference potential corresponding to a WCA division of the Kihara potential. 4. Name of the output file. Output is the quantities described above, namely: GC- GC distance (R), orientational averages of shortest distance (DMED), intermolecular potential (POTMD) and Boltzmann factor (EXPMD). FORTRAN 77 (VAX) Lines of Code: 433 |