Heteronuclear Limit of Strong-Field Ionization: Fragmentation of HeH^{+} by Intense Ultrashort Laser Pulses.

Philipp Wustelt,Max Möller,Florian Oppermann,Stefanie Gräfe,Gerhard G Paulus,Lun Yue,A Max Sayler,Thomas Stöhlker,Manfred Lein

doi:10.1103/physrevlett.121.073203

Philipp Wustelt, Max Möller + Show 7 more

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https://doi.org/10.1103/physrevlett.121.073203

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Abstract

The laser-induced fragmentation dynamics of this most fundamental polar molecule HeH^{+} are measured using an ion beam of helium hydride and an isotopologue at various wavelengths and intensities. In contrast to the prevailing interpretation of strong-field fragmentation, in which stretching of the molecule results primarily from laser-induced electronic excitation, experiment and theory for nonionizing dissociation, single ionization, and double ionization both show that the direct vibrational excitation plays the decisive role here. We are able to reconstruct fragmentation pathways and determine the times at which each ionization step occurs as well as the bond length evolution before the electron removal. The dynamics of this extremely asymmetric molecule contrast the well-known symmetric systems leading to a more general picture of strong-field molecular dynamics and facilitating interpolation to systems between the two extreme cases.

Highlights

Since its first experimental observation in 1925 [1], the HeHþ molecular ion, the simplest polar heteronuclear molecule, has served as a fundamental benchmark system for understanding principles of molecular formation and electron correlation [2]
In contrast to the prevailing interpretation of strong-field fragmentation, in which stretching of the molecule results primarily from laser-induced electronic excitation, experiment and theory for nonionizing dissociation, single ionization, and double ionization both show that the direct vibrational excitation plays the decisive role here
Knowledge of both is required for the general understanding of laser-induced molecular dynamics, which is necessary to form a foundation from which the behavior of more complex molecules can be predicted

Summary

Introduction

Since its first experimental observation in 1925 [1], the HeHþ molecular ion, the simplest polar heteronuclear molecule, has served as a fundamental benchmark system for understanding principles of molecular formation and electron correlation [2]. Heteronuclear Limit of Strong-Field Ionization: Fragmentation of HeH + by Intense Ultrashort Laser Pulses The laser-induced fragmentation dynamics of this most fundamental polar molecule HeHþ are measured using an ion beam of helium hydride and an isotopologue at various wavelengths and intensities.

Results

Conclusion