Strong-field double ionization dynamics of vibrating HeH$^+$ versus HeT$^+$

TL;DR

This study investigates how vibrational dynamics influence double ionization in HeH$^+$ and HeT$^+$ under strong laser fields, revealing distinct electron release patterns and the role of nuclear motion.

Contribution

It provides a comparative numerical analysis of double ionization mechanisms in HeH$^+$ and HeT$^+$, highlighting the effects of nuclear motion and isotopic substitution.

Findings

Electrons prefer to release together along the H(T) side in DI.

Single ionization favors electron escape along the He side.

Nuclear motion enhances simultaneous electron release along the He side.

Abstract

We study double ionization (DI) dynamics of vibrating HeH$^+$ versus its isotopic variant HeT$^+$ in strong laser fields numerically. Our simulations show that for both cases, these two electrons in DI prefer to release together along the H(T) side. At the same time, however, the single ionization (SI) is preferred when the first electron escapes along the He side. This potential mechanism is attributed to the interplay of the rescattering of the first electron and the Coulomb induced large ionization time lag. On the other hand, the nuclear motion increases the contributions of these two electrons releasing together along the He side. This effect differentiates DI of HeH$^+$ from HeT$^+$.