Bond angles for O-H defects in SnO2 from polarization properties of their vibrational modes

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 degrees-68 degrees 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)