Rotational aspects of short-pulse population transfer in diatomic molecules

A fully-selective population transfer scheme for diatomic molecules using short-duration (<ns) laser pulses is developed via the concept of light-induced potentials. It explicitly takes rotational degrees of freedom into account. We apply it to a specific Na₂ transition from the lowest ro-vibrationic state to a single ro-vibrational state of a doubly excited electronic state via an intermediate electronic state. The process insures total selective population transfer with pulses short compared to the molecule rotation time. However, an estimate of the multiphoton ionization rate using time-dependent density functional theory suggests that ionization may significantly adversely affect the transfer.