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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.
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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).
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FORTRAN 77 (VAX)
Lines of Code: 40,000
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