Stability of two-component alkali clusters formed on helium nanodroplets

TL;DR

This study investigates the stability patterns of mixed alkali clusters on helium nanodroplets, revealing electron shell effects and the destabilizing influence of heavy alkali atoms on lighter clusters.

Contribution

It provides new insights into the stability and decay mechanisms of two-component alkali clusters formed on helium nanodroplets using femtosecond laser ionization.

Findings

Stability patterns show electron shell-closure effects.

Mixed clusters decay faster than pure light clusters.

Heavy alkali atoms destabilize light alkali clusters.

Abstract

The stability of two-component clusters consisting of light (Na or K) and heavy (Rb or Cs) alkali atoms formed on helium nanodroplets is studied by femtosecond laser ionization in combination with mass spectrometry. Characteristic stability patterns reflecting electron shell-closures are observed in dependence of the total number of atoms contained in the mixed clusters. Faster decay of the stability of mixed clusters compared to the pure light ones as a function of size indicates a destabilizing effect of heavy alkali atoms on light alkali clusters, presumably due to second order spin-orbit interaction.