910 21 The Electronic Structure of Polyatomic Molecules
years ago. The following is a list of some programs that were available in 2008. All of
these programs can carry out geometry optimization, which means finding conforma-
tions of minimum energy. Websites that are available in 2008 are given, but these are
subject to change.
ArgusLab This program carries out ab initio and semiempirical Hartree–Fock
calculations on a Windows machine (no Macintosh version is available). The AM1
and PM3 methods are available for semiempirical calculations. This program is pro-
vided free for academic use, but other users must pay a licensing fee. The program is
available at http://www.planaria-software.com.
AMPACThis is a comprehensive program that carries out semiempirical molecular
orbital calculations by a variety of methods. It can locate transition states by any
of several procedures and can treat solvated molecules. It does not include ab initio
calculations, but is compatible with Gaussian 03. As of 2008 information is available
at http://www.semichem.com/ampac.
CACheThis title of this package of programs is an abbreviation for Computer Assisted
Chemistry. The package carries out semiempirical calculations, molecular mechanics
calculations, and ab initio calculations with various sets of basis functions. Vibrational
and electronic spectra can be calculated and transition states can be determined. Config-
uration interaction calculations can be carried out. As of 2008 information is available
at http://cachesoftware.com.
Chem3DThis program is part of a package of programs called ChemOffice that
includes ChemDraw and ChemFinder. It carries out molecular mechanics calculations
with the MMR formulas, and can also carry out molecular dynamics calculations, which
are basically integration of classical equations of motion. There is a trial version that
can be used for two weeks without charge, and there is also a demonstration version
that can be used indefinitely but cannot save or print files. Information is available at
http://www.cambridgesoft.com.
GAMESSThis program originated with the research group of M. S. Gordon at the
Ames Laboratory at Iowa State University.^23 It is a free program, and can carry out a
variety of ab initio calculations, as well as electron correlation corrections by means of
configuration interaction, second-order perturbation, and coupled-cluster approaches.
Density-functional calculations can also be carried out as can generalized valence-bond
calculations. As of 2008, it is available at http://www.msg.chem.iastate.edu/gamess/.
GaussianThis program is said to be the most widely used calculational chemistry
program. It has existed in various versions, each labeled by the year in which it appeared.
As of 2003, the newest version is Gaussian 03 and the previous version was Gaussian- It is capable of carrying out just about every kind of quantum chemistry calculation.
Information is available at http://www.gaussian.com.
HyperchemThis program carries out ab initio, density functional, semiempirical, and
molecular mechanics calculations. Molecular dynamics calculations can be carried
out, giving classical trajectories for reactive collisions. A student version is available
at reduced cost. Information is available at http://www.hyper.com.
Jaguar This is a high-speed ab initio program. Information is available at
http://www.schrodinger.com.
MOPACThis package of programs is the most widely used semiempirical program.
It is claimed that it is capable of handling polypeptides and DNA. It is incorporated
(^23) M. W. Schmidt, K. K. Baldridge, J. A. Boatz, S. T. Elbert, M. S. Gordon, J. H. Jensen, S. Koseki,
N. Matsunaga, K. A. Hguyen, S. Su, T. L. Winduw, M. Dupuis, and J. A. Montgomery,J. Comput. Chem.,
14 , 1347–1363 (1993).