The work is aimed at building systematic links between accurate intra-molecular potential energy surfaces (PES) and effective rovibrational Hamiltonians for polyads of near degenerate vibrational states. A specialized computing package MOL_CT of formal rovibrational calculation developed for this purpose for a semi-rigid polyatomic molecule is presented. The general algorithm of high-order calculations, computer implementation and ordering issues are discussed. The package contains a suite of routines for PES and dipole moment surfaces (DMS) analysis, coordinate and axes transformations, change of operator representations, commutator calculations and term reductions. This allows a systematic computer assisted construction of effective rovibrational Hamiltonians for successive polyads starting with a PES for nuclear motion in a give electronic state. Some applications to asymmetric-top triatomic C_2v and C_s molecules with examples using recent accurate PES of water and ozone are briefly discussed.

Date Published: 12 January 2004
PDF: 12 pages
Proc. SPIE 5311, 14th Symposium on High-Resolution Molecular Spectroscopy, (12 January 2004); doi: 10.1117/12.545641

Published in SPIE Proceedings Vol. 5311:
14th Symposium on High-Resolution Molecular Spectroscopy
Leonid N. Sinitsa; Semen N. Mikhailenko, Editor(s)