Lie algebraic description of the rotational spectra of linear triatomic molecules: application to CS2

An algebraic construction of a Hamiltonian is used to study the rotational spectra of linear triatomic molecules on the basis of the subgroup chain of symmetry U-1(4) circle times U-2(4). After considering the rotation-vibrat ion interaction which gives the I splittings, the eigenvalue expression of the Hamiltonian has a form of the term value equation commonly used in the calculation of molecular spectra. The method is applied to calculate the ro tational energy levels of vibrational transitions (0 1 (1)0-0 0 (0)0) for ( CS2)-S-34, (1 1 (1)3-0 1 (1)0) and (1 0 (0)3-0 0 (0)0) for (CS2)-S-32. The obtained rotational constants can represent the rotational spectra of the t hree bands with small root-mean-square frequency errors. The results show t hat the algebraic Hamiltonian can provide an alternative description of rov ibrational spectra for linear triatomic molecules. (C) 2001 Elsevier Scienc e B.V. All rights reserved.