# XUV fluorescence as a probe of interatomic coulombic decay of resonantly excited He nanodroplets

## TL;DR

This paper presents a new method using XUV fluorescence to study the relaxation dynamics of resonantly excited helium nanodroplets over a wide range of timescales.

## Contribution

The novel approach uses XUV fluorescence and nanoplasma ignition to probe interatomic coulombic decay in He nanodroplets.

## Key findings

- XUV fluorescence can detect ICD dynamics in He nanodroplets from femtoseconds to nanoseconds.
- Nanoplasma ignition via tunnel ionization serves as a sensitive probe of relaxation dynamics.
- ICD between roaming He* atoms on the droplet surface is supported by quantum and classical models.

## Abstract

Superfluid He nanodroplets resonantly excited by extreme ultraviolet (XUV) pulses can relax via interatomic coulombic decay (ICD), generally considered an ultrafast process. Here, we introduce a novel approach to probe the dynamics of ICD in He nanodroplets over timescales ranging from femtoseconds to nanoseconds. Our method relies on detecting XUV fluorescence emitted from the nanodroplets as they are driven into a nanoplasma by subsequent intense infrared pulses. Nanoplasma ignition is facilitated by tunnel ionization of XUV-excited He\documentclass[12pt]{minimal}
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