title: Photoabsorption spectra of Na(+)(n) clusters: thermal line-broadening mechanisms.
abstract: Photoabsorption cross sections of small sodium cluster cations ( Na(+)(n), n = 3, 5, 7, and 9) were calculated at various temperatures with the time-dependent local-density approximation in conjunction with ab initio molecular dynamics simulations, yielding spectra that agree with measured ones without ad hoc line broadening or renormalization. Three thermal line-broadening mechanisms are revealed: (I) lifting of level degeneracies caused by symmetry-breaking ionic motions, (II) oscillatory shifts of the entire spectrum caused by breathing vibrations, and (III) cluster structural isomerizations.
authors.affiliation: Theoretische Quantendynamik, Fakultät für Physik, Universität Freiburg, 79106 Freiburg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Moseler
authors.forename: H
authors.initials: H
authors.lastname: Häkkinen
authors.forename: U
authors.initials: U
authors.lastname: Landman