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670. HABIT95: A Program for Predicting the Morphology of
Molecular Crystals as a Function of the Growth
Environment
by G. Clydesdale a,d, K. J. Roberts a,b,d*, R. Docherty c a Department of Pure and Applied Chemistry University of Strathclyde, Glasgow G1 1XL, UK b CCLRC - Daresbury Laboratory, Warrington WA4 4AD, UK c ZENECA Specialties, Hexagon House, P. O. Box 42 Blackley, Manchester M9 3DA, UK d Present address: Department of Mechanical and Chemical Engineering, Heriot-Watt University, Riccarton, Edinburgh EH14 4AS, UK *Communicating author Understanding the shape of crystalline materials is of fundamental importance to crystal scientists. As it also underpins the science and technology behind a range of important industrial processes, it is of great use to be able to model the habit of both homogeneous and heterogeneous systems. The computer program HABIT95 has been developed to aid in such investigations and generally gives good agreement between observed and predicted crystals. Using the internal structure as a starting point, the atom-atom approximation is used to determine the intermolecular interactions in a molecular crystal. Summing all the atom--atom interactions yields the lattice energy. Calculating the interactions along specific crystallographic directions allows the slice and attachment energies to be calculated. The attachment energy is a measure of the relative growth rate along those directions, and consequentlythe growth morphology can be modelled. The effect of solvents/impurities is considered by calculating modified attachment-energy terms leading to simulated habit-modified morphologies. Detailed analysis of intermolecular and interatomic bonding is possible. The program is supplied as source code along with a detailed manual and a number of test input and output files. Special Note: QCPE is distributing this program on a royalty basis. The normal QCPE fee schedule does not apply. The noncommercial price is $600.00; the price to commercial clients is $3,000.00. A signed license agreement is required at the time the order is placed. A copy of the license agreement is enclosed with this issue of the Bulletin. Lines of Code: 6711 FORTRAN 77 (Silicon Graphics) |