A Program for QM/MM Monte Carlo Simulations of Chemical Reactions.
|The MCQUB program package performs Monte Carlo simulations of chemical
reactions and interactions both at the ground and excited states in solution. A unique
(this line was written in 1993, which at that time was unique indeed; now QM/MM is the
method of choice and available in essentially all programs)
feature of the program is that combined quantum mechanical and molecular mechanical
(QM/MM) potentials at the semiempirical level can be used in addition to classical force
fields in these calculations. Capabilities of the MCQUB program includes energy
decompisition analyses, free energy perturbation and umbrella sampling techniques,
polarizable molecular mechanics force fields (QM/MM-PIPF), the Ewald-lattice sum method
for treatment of long-range electrostatic interactions, and simulated annealing
MCQUB with Ab Initio QM/MM Potential with GAMESS.
|The MCQUB-G program has similar capabilities as the MCQUB package
except that ab initio QM methods are used in combined QM/MM calculations. In
addition, the MOVB method is incorporated into the MCQUB-G program allowing for
studies of diabatic and adiabatic free energy surfaces as well as nonequilibrium and solvent reorganization effects
of chemical processes in solution.
The electronic structural calcualtions are
performed using the GAMESS program, which is developed and can be obtained
Professor Mark Gordon at Iowa State University.
A Program for Mixed Molecular Orbital-Valence Bond
|The MOVB program is an electronic structure package, interfaced with GAMESS-US,
for the study of structures, properties, and chemical bonding of localized and delocalized
molecular systems. The block-localized molecular orbital (or Kohn-Sham orbital) method is
used to localize the molecular wave function, while non-orthogonal determinants are used
as configurational state functions in configuration interaction or multiconfiguration
self-consistent-field calculations to determine electronic delocalization effects.
Both wave function theory (WFT) and density functional theory (DFT) can
be used. In the latter approach, the block-localized DFT method is a rigorously defined,
constrained density functional theory,
whereas the multistate DFT (MSDFT) goes beyond the traditional single-determinant
Kohn-Sham DFT by incorporating multistate configuraitonal coupling in DFT calculations.
The MOVB program can also be used for the analysis of intermolecular interaction energies,
employing the block-locazed wavefunction energy decomposition (BLW-ED) method.
A unique feature of the BLW-ED approach is that well-defined intermediate wave functions
for the charge localized species are variationally optimized.
The MOVB program consists of two components that can be used separately.
The first is the BLW program for computation
of electronic structures of block-localized systems. The second program is the MOVB
code that performs valence bond-type calculations.
A Program for Simulaiting Biomolecular Systems.
|CHARMM was developed in the Karplus group at Harvard in the 1980s.
Currently, it has contributions from a group of developers around the world, and it is
maintained and distributed at http://www.charmm.org. The Gao group makes active contributions to the
CHARMM development, including polarizable force fields and combined QM/MM methods.
The current semiempirical QM/MM code, which is the only distributed QM/MM method with
CHARMM was implemented at Minnesota. Importantly,
theoretical and computational methods
developed at Minneosta for studying enzymatic reactions have been implemented into CHARMM,
including computation of kinetic isotope effects using path integral simulations.