Configuration interaction calculations on the P2 molecule. I. Potential energy curves of the X 1Sigmag+ and a 3Sigmau+ states of P2; spectroscopic properties

Abstract

Extended basis set, multireference configuration interaction (CI) calculations have been performed on the ground state (X 1Sigmag+) and the lowest experimentally known excited state (a 3Sigmau+) of P2. Computed spectroscopic constants were found to be in good agreement with the available experimental data. An exception to this is the anharmonicity constant omegac chic of the excited state. The Franck-Condon factors and the pure vibrational transitions for the a 3Sigmau+ to X 1Sigmag+ transition band, which are unknown experimentally have been derived for several vibrational quantum numbers and compared with corresponding values arising from a simulated spectrum based on the use of the Klein-Dunham potential function. Pure rotational transitions within the ground and excited states, calculated for several vibrational and rotational quantum numbers, agree fairly well with the experimental data. The excited state results were found to be in somewhat closer agreement with experiment than the ground state results.