Angle-dependent electron-electron correlation in the single ionization of H2 in strong laser fields

Wan-Yang Wu,Feng He

doi:10.1038/s41598-018-33015-8

Abstract

The one-photon ionization and tunneling ionization of H2 exposed to strong XUV and infrared laser pulses are studied by numerically simulating the four-dimensional time-dependent Schrödinger equation, which includes two-electron dynamics for arbitrary angle between the molecular axis and the laser polarization direction. In the one-photon single ionization of H2, one electron escapes fast and the other bound electron is not disturbed but remains in coherent superposition of two electronic states of {{bf{H}}}_{{bf{2}}}^{{boldsymbol{+}}}. In another case, under the irradiation of strong infrared laser pulses, one electron tunnels through the laser-dressed Coulomb barrier, and the other bound electron has enough time to adapt to the potential of {{bf{H}}}_{{bf{2}}}^{{boldsymbol{+}}} and thus is prone to transfer to the ground electronic state of {{bf{H}}}_{{bf{2}}}^{{boldsymbol{+}}}. In the intermediate regime, between the one photon and tunneling regimes, this electron-electron correlation depends strongly on the laser frequency, laser intensity and on the angle between laser polarization and the molecular axis.

Highlights

Ionization lies at the heart of diverse research directions in atomic and molecular physics, such as high harmonic generation[1,2], photoelectron holography[3], Auger decay[4], shake-off[5,6] and shake-up[7]
Two-electron dynamic has not been yet investigated due to the immense computation effort involved for solving time-dependent Schrödinger equation (TDSE) in six-dimension, which was alleviated by confining both electrons along the molecular axis in these ab initio simulations[36,37]
By looking into the proportion of different electronic states of H+2 before and after the single ionization of H2, one may elucidate the role of the electron-electron correlation during the single ionization process

Summary

Introduction

Ionization lies at the heart of diverse research directions in atomic and molecular physics, such as high harmonic generation[1,2], photoelectron holography[3], Auger decay[4], shake-off[5,6] and shake-up[7]. The photoelectron momentum distributions corresponding to single ionization of H+2 or H2 in XUV fields have been numerically studied[34,35], which show that the photoelectron emission depends sensitively on the photon energy and internuclear distance.

Results

Conclusion