Charging dynamics of dopants in helium nanoplasmas

TL;DR

This study combines experiments and simulations to investigate how dopant atoms influence the ionization and charging processes in helium nanoplasmas under intense NIR laser pulses, revealing dopant-specific effects.

Contribution

It provides new insights into the interplay between dopant ionization and helium nanoplasma ignition, especially highlighting the role of xenon in achieving high charge states.

Findings

Xenon doping leads to high charge states of helium and xenon.

Potassium and calcium doping result in low charge states.

Simulations successfully reproduce experimental charge dynamics.

Abstract

We present a combined experimental and theoretical study of the charging dynamics of helium nanodroplets doped with atoms of different species and irradiated by intense near-infrared (NIR) laser pulses (<10^15 Wcm-2). In particular, we elucidate the interplay of dopant ionization inducing the ignition of a helium nanoplasma, and the charging of the dopant atoms driven by the ionized helium host. Most efficient nanoplasma ignition and charging is found when doping helium droplets with xenon atoms, in which case high charge states both of helium (He2+) and of xenon (Xe^21+) are detected. In contrast, only low charge states of helium and dopants are measured when doping with potassium and calcium atoms. Classical molecular dynamics simulations which include focal averaging generally reproduce the experimental results and provide detailed insights into the correlated charging dynamics of guest and host clusters.