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

A R Bainbridge,E Springate,J Harrington,W A Bryan,R S Minns,C Cacho,A Kirrander

doi:10.1088/1367-2630/17/10/103013

A R Bainbridge, E Springate + Show 5 more

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https://doi.org/10.1088/1367-2630/17/10/103013

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Abstract

Femtosecond vacuum ultraviolet pulses from a monochromated high harmonic generation source excite vibrational wavepackets in the state of D2. The wavepacket motion is measured through strong field ionization into bound and dissociative ion states yielding and D+ products. The time dependence of the 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.

Highlights

Accessing highly excited electronic states of atoms and molecules with a single photon has until recently been limited to studies using synchrotron radiation sources, which provide light that is highly tunable and has narrow bandwidth
When hard x-ray energies are not required, femtosecond VUV to soft x-ray sources based on high harmonic generation (HHG) are an attractive alternative to x-ray free-electron lasers (XFELs)
Light produced via HHG has the advantage over many XFEL sources in that the VUV pulse is strongly time-correlated with the driving laser pulse ensuring that the timing of the VUV pulse is well defined [9]

Summary

October 2015

A R Bainbridge, J Harrington, A Kirrander, C Cacho, E Springate, W A Bryan and R S Minns. Femtosecond vacuum ultraviolet pulses from a monochromated high harmonic generation source excite vibrational wavepackets in the B1S+g state of D2. The wavepacket motion is measured through strong field ionization into bound and dissociative ion states yielding D+2 and D+ products. The time dependence of the 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

Introduction

Experimental

Theoretical

Results and discussion

Summary