• T S Krishnan

      Articles written in Proceedings – Section A

    • Raman spectrum of crystalline ammonium hydrogen malate

      T S Krishnan

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    • Raman spectrum of crystalline cadmium sulphate

      T S Krishnan P S Narayanan

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      The Raman spectrum of a single crystal of cadmium sulphate (3CdSO4.8H2O) has been investigated using the resonance radiation of mercury as exciter. The recorded spectrum reveals 23 Raman lines and of these 8 have been attributed to the internal oscillations of the SO4 ion and 2 to the oscillations of the water molecules. While the number of translatory type of lattice oscillations permitted by the selection rules is 36, only 13 are observed experimentally. A tentative assignment for some of these vibrations has been made from a study of the variation of intensity of the lines with orientation.

    • Raman spectrum of strontianite (SrCO3)

      T S Krishnan

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      The Raman spectrum of strontianite (SrCO3) has been studied for the first time using the λ 2537 resonance radiation of mercury as the exciter. The observed spectrum has been compared with that of aragonite which is isomorphous with strontianite. Out of the 13 frequency shifts recorded, 5 have been attributed to the internal oscillations of the CO3 ion and the remaining 8 to the lattice oscillations. The splitting of the degenerate v4 vibration of the free CO3 ion in the crystal into 3 frequencies and also the observed relative intensity of the lines 150 cm.-1 and 184 cm.-1 arising from the angular oscillations of the CO3 ions about their principal axes of inertia, indicate a considerable distortion in the symmetry of the CO3 ion in strontianite as in the case of aragonite.

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