ExoMol line lists -- LXV. Mid-Infrared rovibronic spectroscopy of isotopologues of NiH

TL;DR

This paper presents comprehensive mid-infrared rovibronic line lists for four isotopologues of nickel monohydride, enabling accurate spectral modeling for temperatures up to 5000 K, based on an empirical spectroscopic model and ab initio calculations.

Contribution

It provides the first extensive line lists for NiH isotopologues covering multiple electronic states and transitions, using a refined empirical model and ab initio dipole moments.

Findings

Line lists cover <10000 cm$^{-1}$ with J up to 37.5.

Applicable for temperatures up to 5000 K.

Line lists are included in the ExoMol database.

Abstract

New line lists for four isotopologues of nickel monohydride, $^{58}$NiH, $^{60}$NiH, $^{62}$NiH, and $^{58}$NiD are presented covering the wavenumber range $<10000$ cm$^{-1}$ ($\lambda > 1$ $\mu$m), $J$ up to 37.5 for transitions within and between the three lowest-lying electronic states, ${X}\,^{2}\Delta$, ${W}\,^{2}\Pi$, and ${V}\,^{2}\Sigma^{+}$. The line lists are applicable for temperatures up to 5000 K. The line lists calculations are based on a recent empirical NiH spectroscopic model [Havalyova et al. J. Quant. Spectrosc. Radiat. Transf., 272, 107800, (2021)] which is adapted for the variational nuclear-motion code Duo. The model consists of potential energy curves, spin-orbit coupling curves, electronic angular momentum curves, spin-rotation coupling curves, $\Lambda$-doubling correction curve for $^2\Pi$ states and Born-Oppenheimer breakdown (BOB) rotational correction curves. New ab initio dipole moment curves, scaled to match the experimental dipole moment of the ground state, are used to compute Einstein A coefficients. The BYOT line lists are included in the ExoMol database at www.exomol.com.