Controlled vibrational quenching of nuclear wave packets in D₂⁺

Ionization of neutral D₂ molecules by a short and intense pump laser pulse may create a vibrational wave packet on the lowest (1sσ_g⁺) adiabatic potential curve of the D₂⁺ molecular ion. We investigate the possibility of manipulating the bound motion, dissociation, and vibrational-state composition of D₂⁺ nuclear wave packets with ultrashort, intense, near infrared control laser pulses. We show numerically that a single control pulse with an appropriate time delay can quench the vibrational state distribution of the nuclear wave packet by increasing the contribution of a selected stationary vibrational state of D₂⁺ to more than 50%. We also demonstrate that a second control pulse with a carefully adjusted delay can further squeeze the vibrational-state distribution, thereby suggesting a multipulse control protocol for preparing almost stationary excited nuclear wave functions. The subsequent fragmentation of the molecular ion with a probe pulse provides a tool for assessing the degree at which the nuclear motion in small molecules can be controlled.