MARVEL analysis of the measured high-resolution spectra of 14NH

• Published in: Journal of molecular spectroscopy Vol. 362; pp. 69 - 76
• Main Authors: Darby-Lewis, Daniel, Shah, Het, Joshi, Dhyeya, Khan, Fahd, Kauwo, Miles, Sethi, Nikhil, Bernath, Peter F., Furtenbacher, Tibor, Tóbiás, Roland, Császár, Attila G., Tennyson, Jonathan
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.08.2019
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/j.jms.2019.06.002

[Display omitted] •Measured Active Rotational-Vibrational Energy Levels technique applied to transitions involving 4 electronic states of NH.•3002 transitions identified from 18 sources.•1058 rovibronic energy levels determined. Rovibronic energy levels are determined for four low-lying electronic states (X3Σ-, A3Π, a1Δ, and c1Π) of the imidogen free radical (14NH) using the Marvel (Measured Active Rotational-Vibrational Energy Levels) technique. Compilation of transitions from both laboratory measurements and solar spectra, found in 18 publications, yields a dataset of 3002 rovibronic transitions forming elements of a measured spectroscopic network (SN). At the end of the MARVEL procedure, the majority of the transitions form a single, self-consistent SN component of 2954 rovibronic transitions and 1058 energy levels, 542, 403, and 58 for the X3Σ-, A3Π, and c1Π electronic states, respectively. The a1Δ electronic state is characterized by 55 Λ-doublet levels, counting each level only once. Electronic structure computations show that unusually the CCSD(T) method does not accurately predict the a1Δ excitation energy even at the complete basis set limit.