VUV excitation of a vibrational wavepacket in D2 measured through strong-field dissociative ionization

Abstract

Femtosecond vacuum ultraviolet pulses from a monochromated high harmonic generation source excite vibrational wavepackets in the ${B}^{1}{{\rm{\Sigma }}}_{{\rm{g}}}^{+}$ state of D _2 . The wavepacket motion is measured through strong field ionization into bound and dissociative ion states yielding ${{\rm{D}}}_{2}^{+}$ and D ^+ products. The time dependence of the ${{\rm{D}}}_{2}^{+}$ and D ^+ ion signals provides a sensitive fingerprint of the quantum nuclear wavepacket, due to the different ionization rates for the two channels. The experiments are modelled with excitation and ionization processes included explicitly, with the results of the model showing a very good agreement with the experimental observations. The experiment demonstrates the level of detail attainable when studying ultrafast quantum nuclear dynamics using high harmonic sources.

Keywords

• high harmonic generation
• photoionization
• vibrational wavepacket
• hydrogen
• chemical physics