P. Bornhauser

Rovibrational Characterization of High-Lying Electronic States of Cu2 by Double-Resonant Nonlinear Spectroscopy

The available knowledge of the electronically excited states of the copper dimer is limited. This is common for transition metals, as the high density of states hinders both experimental assignment and computation. In this work, two-color resonant four-wave mixing spectroscopy was applied to neutral Cu2 in the gas phase. The method yielded accurate positions of individual rovibrational lines in the I-X and J-X electronic systems. This revealed the term symbols for the I and J states as 1Πu (1u) and 1Σu+ (0u+), respectively. For the 63Cu2 isotopologue, accurate molecular constants were obtained. The characterization of the J state finally allowed decisive determination of its electron configuration. The J state is obtained from the ground state by promotion of a 3dπg electron into the weakly bonding 4pπu molecular orbital. From the data analysis, lifetimes of the I state (between 10 ps and 5 ns) and J state (66 ns) were inferred.

RE-VISITING THE ELECTRONIC ENERGY MAP OF THE COPPER DIMER BY DOUBLE-RESONANT FOUR-WAVE MIXING

BRADLEY VISSER, PETER BORNHAUSER, MARTIN BECK, GREGOR KNOPP, Photonics, Paul Scherrer Institute, Villigen, Switzerland; ROBERTO MARQUARDT, CHRISTOPHE GOURLAOUEN, Laboratoire de Chimie Quantique, Institut de Chimie, Université de Strasbourg, 67008 Strasbourg, France; JEROEN A. VAN BOKHOVEN, Energy and Environment, Paul Scherrer Institute, Villigen, Switzerland; PETER RADI, Photonics, Paul Scherrer Institute, Villigen, Switzerland.