Magic Numbers for the Photoelectron Anisotropy in Li-Doped Dimethyl Ether Clusters

TL;DR

This study identifies specific cluster sizes in Li-doped dimethyl ether that exhibit unique photoelectron anisotropy properties, linked to their symmetric charge distribution and coordination shell completion, advancing understanding of solvation effects.

Contribution

It reveals magic numbers at n=4, 5, and 6 in Li(CH3OCH3)n clusters, connecting them to charge symmetry and coordination shell completion, with comparative analysis to Na clusters.

Findings

Magic numbers at n=4, 5, 6 identified

Correlation between cluster size and charge symmetry

Differences explained by solvation and electronic properties

Abstract

Photoelectron velocity map imaging of Li(CH$_3$OCH$_3$)$_n$ clusters (1 $\leq$ n $\leq$ 175) is used to search for magic numbers related to the photoelectron anisotropy. Comparison with density functional calculations reveals magic numbers at n=4, 5, and 6, resulting from the symmetric charge distribution with high s-character of the highest occupied molecular orbital. Since each of these three cluster sizes correspond to the completion of a first coordination shell, they can be considered as 'isomeric motifs of the first coordination shell'. Differences in the photoelectron anisotropy, the vertical ionization energies and the enthalpies of vaporization between Li(CH$_3$OCH$_3$)$_n$ and Na(CH$_3$OCH$_3$)$_n$ can be rationalized in terms of differences in their solvation shells, atomic ionization energies, polarizabilities, metal-oxygen bonds, ligand-ligand interactions, and by cooperative effects.