A general expression of the exact kinetic energy operator in polysphericalcoordinates

This paper aims at presenting a general and compact matrix expression of th e exact kinetic energy operator in polyspherical coordinates adapted to the study of semirigid molecules. The internal coordinates of an N atom system are expressed by a set of N - 1 relative position vectors. The operator ca n be applied to whatever the set of vectors (Jacobi, Radau, valence, satell ite, etc., or a combination of these vectors), and whatever the number of a toms. It includes the rotation and the Coriolis coupling. Such a formulatio n gives the opportunity to develop a general code for calculating the ro-vi brational spectra in a curvilinear description including all the vibrationa l, rotational, and Coriolis couplings. (C) 2001 American Institute of Physi cs.