The surface termination of a Fe (III) spin crossover molecular salt

TL;DR

This study investigates the surface termination of a Fe(III) spin crossover molecular salt, revealing a Ni(dmit)2 preference that affects core level shifts and provides insights into unoccupied molecular orbitals through spectroscopic analysis.

Contribution

It demonstrates the preferential surface termination of Ni(dmit)2 in the salt and links spectroscopic shifts to surface composition and electronic structure.

Findings

Ni(dmit)2 moiety preferentially terminates the surface

Significant core level shift observed for Ni 2p levels

Inverse photoemission indicates unoccupied molecular orbitals related to dmit ligand

Abstract

From a comparison of energy dispersive analyses of X-rays (EDAX), the known molecular stoichiometry and X-ray photoemission spectroscopy (XPS), it is evident that the Fe(III) spin crossover salt [Fe(qsal)2Ni(dmit)2] has a preferential surface termination with the Ni(dmit)2 moiety. This preferential surface termination leads to a significant surface to bulk core level shift for the Ni 2p X-ray photoemission core level, not seen in the corresponding Fe 2p core level spectra. Inverse photoemission spectroscopy (IPES), thus provides some indication of the density of states resulting from the dmit2 = 1,3-dithiol-2-thione-4,5-dithiolato ligand unoccupied molecular orbitals.