Experimental Verification of the Chemical Sensitivity of Two-Site Double Core-Hole States Formed by an X-ray FEL

TL;DR

This study experimentally verifies the chemical sensitivity of two-site double core-hole states in small molecules using X-ray free-electron laser spectroscopy, confirming theoretical predictions about their energy shifts.

Contribution

First experimental verification of the chemical sensitivity of two-site double core-hole states using X-ray FEL spectroscopy on small molecules.

Findings

Confirmed the energy shift differences in DCH states across molecules

Extracted parameters related to chemical sensitivity of DCH states

Validated theoretical models of two-site DCH states

Abstract

We have performed X-ray two-photon photoelectron spectroscopy (XTPPS) using the Linac Coherent Light Source (LCLS) X-ray free-electron laser (FEL) in order to study double core-hole (DCH) states of CO2, N2O and N2. The experiment verifies the theory behind the chemical sensitivity of two-site (ts) DCH states by comparing a set of small molecules with respect to the energy shift of the tsDCH state and by extracting the relevant parameters from this shift.