Optical response of small closed-shell sodium clusters

TL;DR

This paper calculates the optical absorption spectra of small closed-shell sodium clusters using a conserving linear response method, achieving excellent agreement with experiments and providing insights into cluster geometries.

Contribution

It introduces a quasiparticle-based linear response approach for sodium clusters, accurately modeling spectra and inferring geometries from optical data.

Findings

Calculated spectra match experimental data closely.

Resonance features depend on scattering and dephasing effects.

Spectroscopic analysis reveals possible cluster geometries.

Abstract

Absorption spectra of closed-shell Na_2, Na_3+, Na_4, Na_5+, Na_6, Na_7+, and Na_8 clusters are calculated using a recently implemented conserving linear response method. In the framework of a quasiparticle approach, we determine electron-hole correlations in the presence of an external field. The calculated results are in excellent agreement with experimental spectra, and some possible cluster geometries that occur in experiments are analyzed. The position and the broadening of the resonances in the spectra arise from a consistent treatment of the scattering and dephasing contributions in the linear response calculation. Comparison between the experimental and the theoretical results yields information about the cluster geometry, which is not accessible experimentally.