The rovibrational spectrum of BeH, MgH and CaH at high temperatures in\n the $X\\,{}^2\\Sigma^+$ state: a theoretical study

Abstract

Accurate line lists for three molecules, BeH, MgH and CaH, in their ground\nelectronic states are presented. These line lists are suitable for temperatures\nrelevant to exoplanetary atmospheres and cool stars (up to 2000K). A\ncombination of empirical and \\textit{ab initio} methods is used. The\nrovibrational energy levels of BeH, MgH and CaH are computed using the programs\nLevel and DPotFit in conjunction with `spectroscopic' potential energy curves\n(PECs). The PEC of BeH is taken from the literature, while the PECs of CaH and\nMgH are generated by fitting to the experimental transition energy levels. Both\nspin-rotation interactions (except for BeH, for which it is negligible) and\nnon-adiabatic corrections are explicitly taken into account. Accurate line\nintensities are generated using newly computed \\textit{ab initio} dipole moment\ncurves for each molecule using high levels of theory. Full line lists of\nrotation-vibration transitions for $^9$BeH, $^{24}$MgH, $^{25}$MgH, $^{26}$MgH\nand $^{40}$CaH are made available in an electronic form as supplementary data\nto this article and at \\url{www.exomol.com}.\n