Application of R matrix/MQDT method to valence and core excitations in NO

Abstract

Both valence and core excitations of the NO molecule are studied using the R matrix/multi-channel quantum defect theory (MQDT) approach. In the case of valence excitation, the quantum defects and the coupling constant between pπ-Rydberg state and 2Π state of NO were evaluated. The theoretical quantum defects for 2Σ+, 2Π and 2Δ are in good agreement with the experimental values. The theoretical coupling constants not only for B(22Π) but also for L(32Π) are in good agreement with the experimental values. The same approach with some improvements to calculate the R matrix part is used to study the core excitation of NO. The potential curves above the N 1s ionization threshold of NO were calculated. Five potential energy curves responsible for the resonances around 412–414 eV are found. The peak at 412 eV in the absorption spectra of NO may possibly be assigned to the resonances whose character is σ⋆ excitation. On the other hand, the peak at 414 eV in the spectra may possibly be assigned to the resonance whose character is a mixture of multi-electron excitations and σ⋆ excitation.