Time-Resolved Measurement of Interatomic Coulombic Decay in Ne_2

TL;DR

This study measures the lifetime of interatomic Coulombic decay in Ne_2 using a pump-probe experiment with free-electron laser pulses, providing experimental data that agrees with quantum calculations.

Contribution

First direct time-resolved measurement of ICD lifetime in Ne_2 using ultrafast pump-probe spectroscopy.

Findings

ICD lifetime in Ne_2 is approximately 150 fs

Experimental results agree with quantum theoretical predictions

Demonstrates feasibility of ultrafast measurement of interatomic decay processes

Abstract

The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al., Phys. Rev. Lett. 79, 4778 (1997)] in Ne_2 is determined via an extreme ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms, whereupon the ionized dimer undergoes ICD resulting in a repulsive Ne^{+}(2p^{-1}) - Ne^{+}(2p^{-1}) state, which is probed with a second pulse, removing a further electron. The yield of coincident Ne^{+} - Ne^{2+} pairs is recorded as a function of the pump-probe delay, allowing us to deduce the ICD lifetime of the Ne_{2}^{+}(2s^{-1}) state to be (150 +/- 50) fs in agreement with quantum calculations.