Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5376909 | Chemical Physics | 2006 | 10 Pages |
Abstract
The molecular dynamics of a completely rigid molecule is described in terms of external coordinates, namely translations and rotations, and a new algorithm is proposed, which is faster than other known methods and satisfies the constraints up to a desired accuracy. The procedure dispenses with the adoption of Lagrange multipliers and it is derived from an expression previously proposed for the motion of a semirigid molecule, when constraints are imposed to any selected number of intramolecular parameters. The latter need not to be specified for a rigid body but cannot be altogether ignored since it is necessary to guarantee that internal and external coordinates form a complete set of independent variables. This requirement is met by the familiar Eckart-Sayvetz conditions which provide with an iterative procedure for the evaluation, through symmetric orthogonalization, of a matrix of rotation. It turns out that only a first approximation of this matrix is necessary, therefore a final algorithm is proposed, based on the definition of infinitesimal angles of rotation about the mass center.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Natale Neto, Luca Bellucci,