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455. MOPAC: A General Molecular Orbital Package (Version
6.0)
by James J. P. Stewart, Frank J. Seiler Research Laboratory, U. S. Air Force Academy, Colorado 80840 After Version 5.0 of MOPAC was published, several users made available software which they had developed or modified to run on MOPAC. Most of these modifications have been incorporated into Version 6.0. The most important of these are: 1. A geometry optimizer, G-DIIS, written by Csszr and Pulay1, modified to run in MOPAC by Cummings and Gready2. In modifying this code to run in MOPAC 6.0, some efficiency was lost; nonetheless, it does represent an increase in the rate of optimization at an insignificant cost. 2. The electrostatic potential fitting routine of Besler, Merz and Kollman3, as implemented in QCPE 589 (MOPAC 5.0 ESP (Electrostatic Potential)), has been added. 3. The eigenvector following routine of Baker, Jensen, Rzepa and Stebbings has been added. Version 6.0 has several new features. Among these are: 1. A synopsis of the run will be written to the LOG file. This would allow a running job to be monitored. 2. Atoms can be labeled, e.g., C(ortho), N(on C23). 3. Gaussian Z-matrices can be read and printed. 4. Polymer band structures and phonon spectra can be calculated. 5. Up to three lines of keywords can be supplied. 6. In general, the program runs between 15 and 90% faster than Version 5.0. 7. New AM1 elements are available: Si, P, S. 8. New PM3 elements are available: Be, Mg, Zn, Ga, Ge, As, Se, Cd, In, Sn, Ba, Te, Hg, Tl, Pb, Bi4. Porting to Other Machines As with earlier versions, Version 6.0 is written almost entirely in FORTRAN 77; only the CPU time and the date routines are machine specific. Although written only for the VAX computer, MOPAC is designed to allow easy porting to other machines. To facilitate this, the code is extensively documented. In addition to the test data which comes with MOPAC, users can request from QCPE a second, larger set. When this latter set of test calculations runs successfully on a copy of MOPAC ported to a new machine, the new copy can legitimately be described as a faithful copy of version 6.0 and should be given a version number as described in the manual. NOTE:MOPAC 6.0 is available for VAX mainframe, VAX workstations, DECstations and the RS/6000. MOPAC 5.0 is our most recent version for the Silicon Graphics IRIS and Fujitsu mainframe. _________ References: 1. P. Csszr and P. Pulay, J. Mol. Struct. (Theochem), 114, 31 (1984). 2. P. L. Cummins and J. E. Gready, J. Comp. Chem., 10, 939 (1989). 3. B. H. Besler, K. M. Merz and P. A. Kollman, J. Comp. Chem., 11, 431 (1990). 4. J.J.P. Stewart, J. Comp. Chem. (In press; expected publication: Feb. 1991). _________ FORTRAN 77 (VAX) Lines of Code: 40,000 |