CEPA calculations on highly excited states:²Sigma⁺Rydberg series of NO

Abstract

2 Sigma + Rydberg states of the NO molecule have been calculated by ab initio methods up to the 8s sigma state. In addition to the SCF procedure the coupled electron pair approximation (CEPA) has been applied in order to account for electron correlation effects. Quantum defects and partial wave expansion coefficients are presented for states of the Rydberg series ns sigma , np sigma , nd sigma and nf sigma . The energy dependence of the quantum defects and the angular momentum composition of the Rydberg states is discussed. Finally quantum defects and partial wave expansion coefficients obtained by the CEPA method are used for a calculation of electronic transition moments in the Coulomb approximation.