ExoMol line lists - I. The rovibrational spectrum of BeH, MgH and CaH in the<i>X</i> ²Σ⁺state

Abstract

Accurate line lists for three molecules, BeH, MgH and CaH, in their ground elec-tronic states are presented. These line lists are suitable for temperatures relevant to exoplanetary atmospheres and cool stars (up to 2000K). A combination of empirical and ab initio methods is used. The rovibrational energy levels of BeH, MgH and CaH are computed using the programs Level and DPotFit in conjunction with ‘spectro-scopic ’ potential energy curves (PECs). The PEC of BeH is taken from the literature, while the PECs of CaH and MgH are generated by fitting to the experimental tran-sition energy levels. Both spin-rotation interactions (except for BeH, for which it is negligible) and non-adiabatic corrections are explicitly taken into account. Accurate line intensities are generated using newly computed ab initio dipole moment curves for each molecule using high levels of theory. Full line lists of rotation-vibration transi-tions for 9BeH, 24MgH, 25MgH, 26MgH and 40CaH are made available in an electronic form as supplementary data to this article and at www.exomol.com. Key words: molecular data; opacity; astronomical data bases: miscellaneous; planets and satellites: atmospheres; stars: low-mass 1