title: Structural observation of photochromism.
abstract: The reversible formation of a long-lived, coloured F-centre has been observed in small structural changes delineated by neutron diffraction.
authors.affiliation: School of Chemistry, University of Southampton, UK.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Armstrong
authors.forename: Mark T
authors.initials: MT
authors.lastname: Weller