Bond Angles for O-H Defects in Sno2 from Polarization Properties of Their Vibrational Modes

Abstract

Infrared absorption experiments made with polarized light yield significant insights into the possible structures of one- and two-O-H defects in SnO2 that are produced by thermal annealing treatments. These polarized absorption results reveal that a two-O-H defect must involve symmetry-equivalent O-H sites, and that the axes of both one- and two-O-H defects are 63° - 68° from the c-axis of the rutile structure. These O-H bond angles found by experiment restrict the microscopic defect structures that are possible and suggest structures associated with either a metal atom substituting for Sn, or an interstitial metal atom (such as Sn).