title: High-pressure study of isoviolanthrone by Raman spectroscopy.
abstract: Vibrational properties of isoviolanthrone are investigated by Raman scattering at pressures up to 30.5 GPa and room temperature. A complete characterization of phonon spectra under pressure is given for this material. The onset of a phase transition at 11.0 GPa and the formation of a new phase above 13.8 GPa are identified from both the frequency shifts and the changes in the full width half maxima of the intra- and internal modes. The transition is proposed to result from the changes of intra- and intermolecular bonding. The tendencies of the intensity ratios with pressure are in good agreement with the pressure dependence of the resistance at room temperature, indicating that the phase transition may be an electronic origin. The absence of the changes in the lattice modes indicates that the observed phase transition is probably a result of the structural distortions or reorganizations. The reversible character of the transition upon compression and decompression is determined in the entire pressure region studied.
authors.affiliation: Department of Physics, South China University of Technology, Guangzhou 510640, China.
authors.forename: Xiao-Miao
authors.initials: XM
authors.lastname: Zhao
authors.affiliation: Department of Physics, South China University of Technology, Guangzhou 510640, China.
authors.forename: Qiao-Wei
authors.initials: QW
authors.lastname: Huang
authors.affiliation: Department of Physics, South China University of Technology, Guangzhou 510640, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Center for Photovoltaics and Solar Energy, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
authors.forename: Guo-Hua
authors.initials: GH
authors.lastname: Zhong
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China.
authors.forename: Hai-Qing
authors.initials: HQ
authors.lastname: Lin
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China.
authors.forename: Xiao-Jia
authors.initials: XJ
authors.lastname: Chen