Electric field effects on vibrating polar molecules from weak to strong fields

Abstract

Vibrational frequency shifts have been calculated at the MP4(aug-cc-pVTZ) and MP4(cc-pVTZ) ab initio levels for LiH, BH, HF, OH-, HDO, BF, CN- and HC1, in uniform electric fields of varying strength. Vibrational Stark tuning rates as well as strong-field frequency shifts have been computed. All eight molecules studied here display a similar variation of frequency with field: the curves are parabola shaped with negative curvatures. The molecules have different positions of ωmax, but in all cases ωmaxis located close to the field max max strength where ∂µ∥/∂r = 0.