Excitation spectra of a 3He impurity on 4He clusters

TL;DR

This study uses diffusion Monte Carlo to analyze the excitation spectrum of a 3He impurity on 4He clusters, revealing a rotational spectrum pattern and vibrational excitations at higher energies.

Contribution

It provides new insights into the filling order of single-fermion orbits in 3He-4He clusters using advanced quantum Monte Carlo simulations.

Findings

The excitation spectrum resembles a diatomic molecule's rotational spectrum.

Vibrational-like excitations emerge at higher energies for larger clusters.

The study clarifies the orbital filling order in mixed helium clusters.

Abstract

The diffusion Monte Carlo technique is used to calculate and analyze the excitation spectrum of a single 3He atom bound to a cluster with N 4He atoms, with the aim of establishing the most adequate filling ordering of single-fermion orbits to the mixed clusters with a large number of 3He atoms. The resulting ordering looks like the rotational spectrum of a diatomic molecule, being classified only by the angular momentum of the level, although vibrational-like excitations appear at higher energies for sufficiently large N.