Postpulse alignment of molecules robust to thermal averaging

Abstract

Alignment of molecules under field free conditions with negligible vibrational or electronic excitation is created by a short off-resonant low frequency laser pulse. Typically the global maximum in postpulse alignment occurs at a rotational wave packet revival close to half a rotational period after the short pulse. The alignment effect is robust to thermal averaging at the revivals, but averaging cancels the alignment in between. The permanent dipole–field interaction can be efficient for alignment with off-resonant frequencies between the rotational and the vibrational frequencies of the molecule.