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Statistical thermodynamics of internal rotation in a hindering potential of mean force obtained from computer simulations.

Authors
Hnizdo-V; Fedorowicz-A; Singh-H; Demchuk-E
Source
J Comput Chem 2003 Jul; 24(10):1172-1183
NIOSHTIC No.
20023024
Abstract
A method of statistical estimation is applied to the problem of one-dimensional internal rotation in a hindering potential of mean force. The hindering potential, which may have a completely general shape, is expanded in a Fourier series, the coefficients of which are estimated by fitting an appropriate statistical-mechanical distribution to the random variable of internal rotation angle. The function of reduced moment of inertia of an internal rotation is averaged over the thermodynamic ensemble of atomic configurations of the molecule obtained in stochastic simulations. When quantum effects are not important, an accurate estimate of the absolute internal rotation entropy of a molecule with a single rotatable bond is obtained. When there is more than one rotatable bond, the marginal statistical-mechanical properties corresponding to a given internal rotational degree of freedom are reduced. The method is illustrated using Monte Carlo simulations of two public health relevant halocarbon molecules, each having a single internal-rotation degree of freedom, and a molecular dynamics simulation of an immunologically relevant polypeptide, in which several dihedral angles are analyzed.
Keywords
Statistical-analysis; Computer-models; Chemical-properties; Chemical-processing; Thermodynamics; Molecular-structure
Contact
National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505-2888
CODEN
JCCHDD
CAS No.
107-06-2
Publication Date
20030730
Document Type
Journal Article
Email Address
vbh5@cdc.gov
Fiscal Year
2003
NTIS Accession No.
NTIS Price
Issue of Publication
10
ISSN
0192-8651
NIOSH Division
HELD
Source Name
Journal of Computational Chemistry
State
WV
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