Sub-10-fs control of dissociation pathways in the hydrogen molecular ion with a few-pulse attosecond pulse train.

Yasuo Nabekawa,Kaoru Yamanouchi,Tomoya Okino,A Amani Eilanlou,Yusuke Furukawa,Katsumi Midorikawa,Eiji J Takahashi

doi:10.1038/ncomms12835

Abstract

The control of the electronic states of a hydrogen molecular ion by photoexcitation is considerably difficult because it requires multiple sub-10 fs light pulses in the extreme ultraviolet (XUV) wavelength region with a sufficiently high intensity. Here, we demonstrate the control of the dissociation pathway originating from the 2pσu electronic state against that originating from the 2pπu electronic state in a hydrogen molecular ion by using a pair of attosecond pulse trains in the XUV wavelength region with a train-envelope duration of ∼4 fs. The switching time from the peak to the valley in the oscillation caused by the vibrational wavepacket motion in the 1sσg ground electronic state is only 8 fs. This result can be classified as the fastest control, to the best of our knowledge, of a molecular reaction in the simplest molecule on the basis of the XUV-pump and XUV-probe scheme.

Highlights

The control of the electronic states of a hydrogen molecular ion by photoexcitation is considerably difficult because it requires multiple sub-10 fs light pulses in the extreme ultraviolet (XUV) wavelength region with a sufficiently high intensity
We show the kinetic energy release (KER) spectra of H þ fragments along the z direction and x direction in Fig. 2 as a fine blue curve with a shaded area and a thick red curve, respectively, to clearly exhibit the new fragment components as distinct peaks, which are labelled with their harmonic orders
We find that the H9 and H11 KER components oscillate at delay times of around 0 and 280 fs in a similar manner to the oscillation found in the H3 and H5 components, while there seems to be no clear oscillation at other delay times for the H9 and H11 KER components and in the whole range of the delay times for the H7 KER component

Summary

Introduction

The control of the electronic states of a hydrogen molecular ion by photoexcitation is considerably difficult because it requires multiple sub-10 fs light pulses in the extreme ultraviolet (XUV) wavelength region with a sufficiently high intensity. The switching time from the peak to the valley in the oscillation caused by the vibrational wavepacket motion in the 1ssg ground electronic state is only 8 fs. This result can be classified as the fastest control, to the best of our knowledge, of a molecular reaction in the simplest molecule on the basis of the XUV-pump and XUV-probe scheme. An XUV attosecond pulse train (APT) composed of discrete HH components has been useful for investigating the electronic states in H2 and H2þ (refs 21,24)

Methods

Results

Conclusion