Theoretical spectroscopy of O 1s and N 1s excited states of N₂O

The O 1s and N 1s excited states of N₂O (nitrous oxide, N _t-N_c-O) have been investigated by the symmetry-adapted cluster-configuration interaction (SAC-CI) method. Our approach in this series of works using high-resolution angle-resolved ion-yield (ARIY) spectroscopy and the SAC-CI method is reviewed for the O 1s excited states of N₂O. The vibrational structure observed by ARIY spectroscopy was interpreted by two-dimensional ab initio potential energy surfaces (2D PESs). The valence-Rydberg coupling was analyzed by the electronic part of the second moment, 〈r²〉. The thermal effect in the core-electron excitation spectrum was examined by the PES calculations in the bending coordinate. The 2D PESs of the N_t and N_c excited states have also been calculated by the SAC-CI method and are discussed in detail.