Article révisé par les pairs
Résumé : The dynamics of rigid polyatomic systems, either molecules or rigid portions of large molecules, is described by cartesian equations of motion for its atoms. In comparison with the original version of the method of constraints [1], the present approach has more general applicability, on account of a proper choice of holonomic constraints. Moreover, it always leads to a more efficient molecular dynamics simulation of polyatomic molecules. The dynamics of a rigid unit is provided by the motion of a ‘basic’ subset of atoms: two for a linear molecule, three for a planar one, four for a tridimensional one. Explicit cartesian equations of motion of the ‘basic’ atoms are derived from first principles. Verlet algorithm is shown to be particularly advantageous in their numerical integration. Illustrations are given for various molecular geometries, i.e. liquid CS2, benzene and CCl4. © 1982 Taylor & Francis, Ltd.