A quantum simulation of dissociative ionization of $H_2^+$ in full dimensionality with time dependent surface flux method

TL;DR

This paper presents a full-dimensional quantum simulation of $H_2^+$ dissociative ionization under laser pulse, accurately computing energy spectra and dissociation directions without relying on quantum chemistry data.

Contribution

It introduces a novel three-particle time-dependent Schrödinger equation simulation using the tSurff method, achieving results consistent with experimental data and surpassing previous 2D computational limitations.

Findings

Energy sharing observed in JES with peaks at 2-4 eV

Ground energy matches quantum chemistry results when proton kinetic energy is excluded

Dissociation occurs mainly along the laser polarization direction

Abstract

The dissociative ionization of $H_2^+$ in a linearly polarized, 400 nm laser pulse is simulated by solving a three-particle time-dependent Schr\"odinger equation in full dimensionality without using any data from quantum chemistry computation. The joint energy spectrum (JES) is computed using a time-dependent surface flux (tSurff) method, the details of which are given. The calculated ground energy is -0.597 atomic units and internuclear distance is 1.997 atomic units if the kinetic energy term of protons is excluded, consistent with the reported precise values from quantum chemistry computation. If the kinetic term of the protons is included, the ground energy is -0.592 atomic units with an internuclear distance 2.05 atomic units. Energy sharing is observed in JES and we find peak of the JES with respect to nuclear kinetic energy release (KER) is within $2\sim4$ eV, which is different from the previous two dimensional computations (over 10 eV), but is close to the reported experimental values. The projected energy distribution on azimuth angles shows that the electron and the protons tend to dissociate in the direction of polarization of the laser pulse.