Controlled vibrational quenching of nuclear wave packets in D$_2^+$
Thomas Niederhausen and Uwe Thumm

Ionization of neutral $D_2$ molecules by a short and intense pump laser pulse may create a vibrational wave packet on the lowest ($1s\sigma_g^+$) adiabatic potential curve of the $D_2^+$ molecular ion. We investigate the possibility of manipulating the bound motion, dissociation, and vibrational--state composition of $D_2^+$ nuclear wave packets with ultra--short, 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 $D_2^+$ 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 multi--pulse 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.

© 2008 The American Physical Society.