ExoMol line lists - I. The rovibrational spectrum of BeH, MgH and CaH in the X2Σ+ state

Accurate line lists for three molecules, BeH, MgH and CaH, in their ground electronic states are presented. These line lists are suitable for temperatures relevant to exoplanetary atmospheres and cool stars (up to 2000 K). 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 spectroscopic 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 transition 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 rotationvibration transitions for 9BeH, 24MgH, 25MgH, 26MgH and 40CaH are made available in an electronic form as supporting information to this paper and at www.exomol.com.