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

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 U1(4)⊗U2(4). After considering the rotation–vibration interaction which gives the l 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 rotational energy levels of vibrational transitions (0 1 10–0 0 00) for C 34S2, (1 1 13–0 1 10) and (1 0 03–0 0 00) for C 32S2. The obtained rotational constants can represent the rotational spectra of the three bands with small root-mean-square frequency errors. The results show that the algebraic Hamiltonian can provide an alternative description of rovibrational spectra for linear triatomic molecules.