The permanent electric dipole moments of calcium monohydride, CaH.

Numerous branch features in the (0,0) A 2Pi-X 2Sigma+ band system of calcium monohydride CaH have been studied by optical Stark spectroscopy. The Stark shifts, Stark splittings, and appearance of electric-field-induced transitions in the high resolution laser-induced fluorescence spectra are analyzed to produce values for the magnitude of the permanent electric dipole moments mid R:micromid R: of 2.94(16) D and 2.372(12) D for the X 2Sigma+(v=0) and A 2Pi(v=0) states, respectively. A comparison with values predicted from a semiempirical electrostatic model and previous ab initio calculations for mid R:micromid R: (X 2Sigma+) is presented. The change in mid R:micromid R: upon excitation from the X 2Sigma+ state to the A 2Pi state is rationalized using a simple molecular orbital description.