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QCMP053. MOLSV: Calculation of Molecular Volume
and Surface Area
by Graham M. Smith, Merck Sharp and Dohme
Research Laboratories, Rahway, New Jersey
07065 (QCPE 509)
Converted by K. J. Tupper, QCPE The method used to calculate the volume is based on a numerical integration using a nearly uniform distribution of points inside a sphere. The integration is done atom by atom using the following procedure. A unit sphere containing 1800 points is scaled to the size of the atom being considered and moved to be centered at the atomic center. Then, for every atom which overlaps the atom in question, a plane is constructed perpendicular to the connecting line which then passes through the point of the intersection of the two atomic surfaces. All points which lie on the side of the plane away from the atomic center are discarded. When this process is done, the unique volume for this atom can be calculated as the product of the number of points remaining and the volume per point value obtained by dividing the original atom volume by 1800. This is repeated for all atoms in the structure and a final sum is taken to obtain the overall volume. FORTRAN 77 (Microsoft 3.31) Lines of Code: 1100 |