Theoretical study of the CsH molecule: adiabatic and diabatic potential energy curves and dipole moments

For nearly all states dissociating below the ionic limit, we perform an adiabatic and diabatic study for 1Σ+ and 3Σ+ electronic states dissociating into Cs (6s, 6p, 5d, 7s, 7p, 6d, 8s and 4f) + H (1s). Furthermore, we present the adiabatic results for the 1-5 1,3Π and 1-3 1,3Δ states. The calculations rely on an ab initio pseudopotential, semi-empirical operator core-valence correlation and full valence CI approaches, combined to an efficient diabatization procedure. For the low-lying states, our spectroscopic constants and vibrational level spacing are in very good agreement with the available experimental data. Diabatic potentials and dipole moments are analysed, revealing the strong imprint of the ionic state in the 1Σ+ adiabatic states. The H electron affinity correction was accounted for by the use of the efficient diabatization method. This leads to a better agreement with the available experimental data. Experimental suggestions are also given for the higher excited states based on their unusual behaviour