title: Temperature dependence of the crystal structure and g-values of [(HC(Ph2PO)3)2Cu](ClO4)2.2H2O: influence of dynamic Jahn-Teller coupling and lattice strain interactions.
abstract: The temperature dependence of the X-ray crystal structure and powder EPR spectrum of [(HC(Ph(2)PO)(3))(2)Cu](ClO(4))(2).2H(2)O is reported, and the structure at room temperature confirms that reported previously. Below approximately 100 K, the data imply a geometry with near elongated tetragonal symmetry for the [(HC(Ph(2)PO)(3))(2)Cu](2+) complex, but on warming the two higher Cu-O bond lengths and g-values progressively converge, and by 340 K the bond lengths correspond to a compressed tetragonal geometry. The data may be interpreted satisfactorily assuming an equilibrium among the energy levels of a Cu-O(6) polyhedron subjected to Jahn-Teller vibronic coupling and a lattice strain. However, agreement with the experiment is obtained only if the orthorhombic component of the lattice strain decreases to a negligible value as the temperature approaches 340 K.
authors.affiliation: Division of Natural Sciences, University of Hawaii at Hilo, Hawaii 96720-4091, USA. simmonsc@hawaii.edu
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Simmons
authors.forename: Horst
authors.initials: H
authors.lastname: Stratemeier
authors.forename: Graeme R
authors.initials: GR
authors.lastname: Hanson
authors.forename: Michael A
authors.initials: MA
authors.lastname: Hitchman