Ab-initio potential energy curves of valence and Rydberg electronic states of the PO radical

• Published in: Computational and theoretical chemistry Vol. 1049; pp. 102 - 108
• Main Authors: Izzaouihda, Safia, Abou El Makarim, Hassna, Komiha, Najia, Lahmar, Souad, Ghalila, Hassen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2014
• Subjects: Electronic states; Highly correlated quantum chemistry methods; Potential energy curves; Predissociation; Spectroscopic constants; Spin-orbit couplings; Electronic states; Potential energy curves; Predissociation; Spectroscopic constants; Highly correlated quantum chemistry methods; Spin-orbit couplings
• ISSN: 2210-271X
• DOI: 10.1016/j.comptc.2014.10.001

Simulated vibrational spectra of PO (transitions between ground state and valence doublet and Rydberg states). [Display omitted]
•Potential energy curves have been calculated and for 13 electronic states of PO radical.•Highly correlated ab initio methods MRCI/aV5Z are used.•The spectroscopic constants and vibrational energy levels determined.•The spin-orbit couplings between interacting states are calculated.•The theoretical vibrational spectrum shows very intense peaks involving the Rydberg states.
This paper reports a theoretical study of the electronic states of PO radical. Highly correlated ab initio methods were used for mapping the potential energy curves. Internally contracted multi-reference configuration interaction method with the augmented correlation-consistent basis set (aV5Z) has been employed to carry out the study. After the nuclear motion treatment, the spectroscopic constants and the vibrational energy levels of the doublet and quartet electronic states are determined. The calculated values have been found in a good agreement with the existing experimental and theoretical results. The spin-orbit couplings between interacting states were also determined in the region where the crossings of the potential energy curves occurs. These couplings are capable to induce predissociation processes involving quartet states and producing P and O atoms at their ground and low lying excited electronic states. The theoretical vibrational spectrum was predicted using the Franck Condon factors and the transition moments integrals. The calculated spectrum shows intense peaks involving the Rydberg states in complete accordance with the experiment.