|
QCMP145. QCFF/PI - CFFTH2 (DOS Version of QCPE 593)
by A. K. Ponamaneni and T. G. Lenz, Department of
Chemical Engineering, and A. K. Rappe and J. D.
Vaughan, Department of Chemistry, Colorado State
University, Fort Collins, Colorado 80523
DOS Version of QCFF/PI-CFFTH
This version includes an extension for the computation
of S(T), Cp(T), (H(T)-H(O))/T and (G(T)-G(O))/T for
organic compounds consisting of nitrogen and halogens
and can accept as input the output files of various
commercial graphics software. It includes the
capability to treat heteroatomic molecules having
carbon, hydrogen, oxygen, nitrogen and halogen atoms.
Some of the subroutines have been modified so there is
no need for the input of a symbolic formula. This
version can run on an IBM-compatible AT 486 PC and can
read the coordinate and connectivity information from
the output of commercial graphics software.
QCFF/PI
This is the quantum mechanical extension of the
consistent force field to PI-electron systems by A.
Warshel and M. Levitt (revised version, 1973).
QCFF/PI calculates equilibrium conformations and
vibrational normal modes of ground and PI excited
states of large conjugated molecules as well as the
ground state of hydrocarbons (for which the potential
parameters were available). The oscillator strength
for PI transitions and I. R. intensities of the ground
electronic state are calculated. Equilibrium
geometries are calculated by the minimization of the
molecular energy with the complete set of 3N Cartesian
coordinates. The vibrational normal modes are then
calculated by the diagonalization of the matrix of the
second derivatives of the potential with respect to the
mass-scaled Cartesian coordinates at the calculated
minimum. The efficiency of the program is based on the
availability of analytic first and second derivatives
of the potential with respect to the Cartesian
coordinates. For more information, see references 1-6
in the documentation.
Features Added in QCFF/PI-CCFTHH (QCPE 593)
The feature added in this version was a capability to
compute the ideal gas entropy, the ideal gas heat
capacity, the difference in the ideal gas enthalpy at
the given temperature from its value at 0 degrees K and
also the difference between the Gibbs free energy at a
given temperature and its value at 0 degrees K. These
thermodynamic quantities are obtained by use of the
rigid rotor and harmonic oscillator models of
statistical thermodynamics.
Lines of Code: 8370
FORTRAN77 (MICROSOFT)
| 
