Studies on the electric dipole moment function and line parameters for high overtone bands of NO

- The EDMF was first directly fitted for the spin-orbit splitting of nitric oxide.
- Ab initio EDMF is more close to three fitting ones than the previous theoretical one.
- The vibrational transition moments agree well with experiments at large overtone.
- The calculated line intensities agree well with measurements.

An accurate electric dipole moment function (EDMF) has been obtained by fitting the best available data including the pure rotational band 0-0 for individual ro-vibrational transitions for nitric oxide. Line intensities calculated using the fitted EDMF agree better with the measurements than the current HITRAN database. Moreover, the accurate ab initio potential energy curve (PEC) and EDMF were found using the multi-reference averaged quadratic coupled-cluster (AQCC) approach with the basis set aug-cc-pV6Z (aV6Z). The good agreement of the vibrational transition moments, computed using the Rydberg-Klein-Rees (RKR) potential and the fitted EDMFs, with experiments shows the present fitted EDMF could be more accurate than other fitted ones at the valid range. Our ab initio vibrational transition moments agree better with experimental data than the ones calculated using the previous theoretical PEC and EDMF, especially at the high overtones. We expect that the present study will be helpful for the transitions including high υ and high overtone bands of NO.