Electric-field-induced adiabaticity in the rovibrational motion of heteronuclear diatomic molecules

We investigate the rovibrational dynamics of heteronuclear diatomic molecules exposed to a strong external static and homogeneous electric field. We encounter in the presence of the field the effect of induced adiabatic coupling among the vibrational and hybridized rotational motions. Exact results are compared to the predictions of the adiabatic rotor approach as well as to the previously established effective rotor approximation. A detailed analysis of the impact of the electric field is performed: the hybridized and oriented rotational motion, the mixing of angular momenta, and the squeezing of the vibrational motion are observed. It is demonstrated that these effects can well be accounted for by the adiabatic rotor approximation.