SHARP VIBRONIC SPECTRA OF CU(II) DOPED CS2ZRCL6

The low temperature electronic spectrum of Cu(II) doped Cs2ZrCl6 is re ported. It is found that Cu(II) is incorporated as the square planar c opper tetrachloride ion, CuCl42-, which substitutes at the Zr(IV) site in the Cs2ZrCl6 lattice. There is a complete absence of axial coordin ation. The optical spectrum shows vibronic structure with peak widths as small as 8 cm(-1), far narrower than previously seen for this ion. The energy of the observed transitions and the Franck-Condon intensity pattern suggest that there is a substantial relaxation of the host la ttice about the impurity ion. The relative intensity of the magnetic d ipole component of the bands appears to be considerably greater than f or pure copper(II) compounds containing the CuCl42- ion. (C) 1998 Else vier Science B.V. All rights reserved.