title: Substitutional photoluminescence modulation in adducts of a europium chelate with a range of alkali metal cations: a gas-phase study.
abstract: We present gas-phase dispersed photoluminescence spectra of europium(III) 9-hydroxyphenalen-1-one (HPLN) complexes forming adducts with alkali metal ions ([Eu(PLN)3M](+) with M = Li, Na, K, Rb, and Cs) confined in a quadrupole ion trap for study. The mass selected alkali metal cation adducts display a split hypersensitive (5)D0 → (7)F2 Eu(3+) emission band. One of the two emission components shows a linear dependence on the radius of the alkali metal cation whereas the other component displays a quadratic dependence thereon. In addition, the relative intensities of both components invert in the same order. The experimental results are interpreted with the support of density functional calculations and Judd-Ofelt theory, yielding also structural information on the isolated [Eu(PLN)3M](+) chromophores.
authors.affiliation: Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT) , Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Greisch
authors.forename: Michael E
authors.initials: ME
authors.lastname: Harding
authors.forename: Bernhard
authors.initials: B
authors.lastname: Schäfer
authors.forename: Martin
authors.initials: M
authors.lastname: Rotter
authors.forename: Mario
authors.initials: M
authors.lastname: Ruben
authors.forename: Wim
authors.initials: W
authors.lastname: Klopper
authors.forename: Manfred M
authors.initials: MM
authors.lastname: Kappes
authors.forename: Detlef
authors.initials: D
authors.lastname: Schooss