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      Permanent link:
      https://www.ias.ac.in/article/fulltext/seca/069/06/0307-0315

    • Keywords

       

      Electron Paramagnetic Resonance; Line Width; Electron Paramagnetic Resonance Spectrum; Liquid Nitrogen Temperature; Alkali Halide

    • Abstract

       

      Electron paramagnetic resonance (EPR) of VO2+ radicals incorporated in face-centred single crystals of NaCl, KC1 and RbCl has been studied in the temperature range of 77° K to 330° K. At liquid nitrogen temperature, anisotropic spectra have been recorded in each case while spectra recorded at room and higher temperatures are isotropic suggesting the existence of a fast readjustment of VO2+ molecular ions in the crystals at higher temperature while this motion gets hindered at liquid nitrogen temperatures. Spin-Hamiltonian constants are calculated from the recorded isotropic and anisotropic spectra. The line widths in each case are found to obey a parabolic law originally proposed by Kivelson. The constants which give a close fit have been evaluated. The random orientation and readjustment of V-0 bond in these alkali chloride crystals is explained on the assumption that the medium exhibits a “liquid-like” nature for VO2+ molecular ion as far as the electron paramagnetic resonance absorption is concerned.

    • Author Affiliations

       

      A V Jagannadham1 Putcha Venkateswarlu2

      1. Department of Physics, Indian Institute of Technology, Kanpur, India
      2. Department of Physics, University of California, Santa Barbara, California
    • Dates

       
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