Molecular rotational dynamics in nonadiabatically switching homogeneous electric fields

Abstract

We investigate the rotational dynamics of heteronuclear diatomic molecules possessing a ${^{1}\ensuremath{\Sigma}}^{+}$ electronic ground state exposed to a strong external time-dependent homogeneous electric field. An exponential switching on and off is employed for the electric field. We analyze the orientation and hybridization of the angular motion, together with the population of pendular and rotational states in the constant-field and field-free regimes, as the switching times are modified. Exact results are compared with those of an $N$-mode approach to the rotational dynamics derived within the effective rotor approximation. It is demonstrated that robust predictions are possible with respect to the number of pendular states and partial waves involved in the constant and postpulse regimes, respectively. The final wave packet shows a wide variety of localization and orientation phenomena arranged in characteristic patterns, which alternate between two angular hemispheres and are periodic in time.