ExoMol molecular line lists - X. The spectrum of sodium hydride

Abstract

Accurate and complete rotational, rotational-vibrational and rotational-vibrational-electronic line lists are calculated for sodium hydride: both the NaH and NaD isotopologues are considered. These line lists cover all ro-vibrational states of the ground (X 1Σ+) and first excited (A 1Σ+) electronic states. The calculations use available spectroscopically-determined potential energy curves and new high-quality, ab initio dipole moment curves. Partition functions for both isotopologues are calculated and the effect of quasi-bound states is considered. The resulting line lists are suitable for temperatures up to about 7000 K and are designed for studies of exoplanet atmospheres, brown dwarfs and cool stars. In particular, the NaH A - X band is found to show a broad absorption feature at about 385 nm which should provide a signature for the molecule. All partition functions, lines and transitions are available as supplementary information to this article and at www.exomol.com.