title: Surprising luminescent properties of the polyphosphates Ln(PO3)3:Eu (Ln = Y, Gd, Lu).
abstract: The optical emission properties of the lanthanoid catena-polyphosphates Ln(PO(3))(3) (Ln = Y, Gd, Lu) doped with europium were investigated. Incommensurately modulated β-Y(PO(3))(3):Eu (super space group Cc (0|0.364|0)0) and Gd(PO(3))(3):Eu (space group I2/a) show the usual emission characteristics of Eu(3+), while in Lu(PO(3))(3):Eu (space group Cc) the europium is unprecedentedly partially reduced to the divalent state, as proven by both a broad emission band at 406 nm excited at 279 nm and an EPR spectroscopic investigation. (151)Eu-Mössbauer spectroscopy showed that only a very small part of the europium is reduced in Lu(PO(3))(3):Eu. An explanation for this unusual behaviour is given.
authors.affiliation: Institut für Physik, Universität Augsburg, Universitätsstrasse 1, D-86159, Augsburg, Germany. henning@ak-hoeppe.de
authors.forename: Henning A
authors.initials: HA
authors.lastname: Höppe
authors.forename: Karolina
authors.initials: K
authors.lastname: Kazmierczak
authors.forename: Sylwia
authors.initials: S
authors.lastname: Kacprzak
authors.forename: Inga
authors.initials: I
authors.lastname: Schellenberg
authors.forename: Rainer
authors.initials: R
authors.lastname: Pöttgen