Resonance Raman and far-infrared studies of isotopically disordered and mixed-halide halogen-bridged platinum chain solids

• Published in: Synthetic metals 1993-04, Vol.56 (2), p.3335-3340
• Main Authors: Love, S.P., Worl, L.A., Donohoe, R.J., Huckett, S.C., Saxena, A., Huang), X.Z., Bishop, A.R., Swanson, B.I.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Lattice dynamics; Localized modes; Phonons and vibrations in crystal lattices; Physics
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/0379-6779(93)90124-F

The MX chain solids [Pt(en) 2][Pt(en) 2X 2](ClO 4) 4, (en = C 2H 8N 2 and X=Cl, Br), referred to as “PtX”, are used to explore some of the surprising spectral consequences of disorder in 1-D systems, first for pure PtCl, where the disorder arises from randomly distributed Cl isotopes, then for the more drastic case of the mixed-halide materials PtCl 1−xBr x. Lattice dynamics and Peierls-Hubbard modelling are used to analyze the observed spectral behavior. In both cases, the complex structure seen in the Raman and IR spectra is found to arise from strongly localized vibrational modes residing on chain segments, defined by sequences of Cl isotopes for PtCl, and by sequences of Cl and Br for PtCl 1−xBr x.