Mass-ratio dependent strong-field dissociation of artificial helium hydride isotopologues

TL;DR

This study investigates how the nuclear mass ratio influences the strong-field dissociation of artificial helium hydride isotopologues, revealing that specific mass ratios can significantly suppress vibrational excitation and dissociation.

Contribution

It introduces a novel approach by fixing the reduced mass and varying the mass ratio to isolate effects of mass asymmetry on dissociation dynamics.

Findings

Vibrational excitation is strongly suppressed at certain mass ratios.

Dissociation probability decreases by orders of magnitude at specific mass ratios.

Classical and quantum simulations agree on the mass ratio effects.

Abstract

We study the effect of the nuclear-mass ratio in a diatomic molecular ion on the dissociation dynamics in strong infrared laser pulses. A molecular ion is a charged system, in which the dipole moment depends on the reference point and therefore on the position of the nuclear center of mass, so that the laser-induced dynamics is expected to depend on the mass asymmetry. Whereas usually both the reduced mass and the mass ratio are varied when different isotopologues are compared, we fix the reduced mass and artificially vary the mass ratio in a model system. This allows us to separate effects related to changes in the resonance frequency, which is determined by the reduced mass, from those that arise due to the mass asymmetry. Numerical solutions of the time-dependent Schr\"odinger equation are compared with classical trajectory simulations. We find that at a certain mass ratio, vibrational excitation is strongly suppressed, which decreases the dissociation probability by many orders of magnitude.