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

摘要

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 HCl, in uniform electric fields of varying strength. Vibrational Stark tuning rates as well as strong-field frequency shifts have been c.omputed. 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 ω_(max), but in all cases ω_(max) is located close to the field strength where (partial deriv)μ_‖(partial deriv)r = 0.