• P K Narayanaswamy

      Articles written in Proceedings – Section A

    • Raman spectra of methyl alcohol, ethyl alcohol andn-heptane

      P K Narayanaswamy

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    • Influence of temperature on the Raman spectra of crystals - Part I. Calcite

      P K Narayanaswamy

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      With the λ 2536 radiation of the mercury arc as exciter, the Raman spectrum of calcite has been studied at the temperatures 90°, 185°, 300°, 343°, 398°, 438°, 508°, 583°, 638° and 698° K. It is found thatall the Raman lines exhibit definite decrease in frequency shifts with increase in temperature, the decrease being much greater in the case of the lattice lines than in the internal oscillations of the CO3 group. The width of the Raman lines increases with temperature and this increase is of the same order of magnitude in each case as the diminution of frequency shift, the former being always greater than the latter. The temperature-frequency shift, and the temperature-width curves for the various. Raman lines exhibit a striking similarity in shape, tending to flatten up at low temperatures and the rate of change being greater at high temperature, suggesting a close relationship between the two. The peak intensity of the Raman lines is also found to decrease very much with rising temperature.

    • Influence of temperature on the Raman spectra of crystals - Part. II. Quartz

      P K Narayanaswamy

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      The Raman spectrum of quartz has been studied at a series of nine temperatures from 85° to 685°K. Data regarding the variations in frequency shiftdv, breadth and the proportional changed logv/dT are furnished for twelve of the important Raman lines of quartz. The proportional change is found to decrease progressively with the frequency shift of the Raman line, being highest for the low frequency lines and lowest for the high frequency ones. The temperature-frequency shift and the temperature-width curves for the individual Raman lines show similar characteristics, tending to flatten up at low temperatures and the rate of change being greater at high temperatures. The peak intensity of the Raman lines is also found to decrease markedly with rising temperature.

    • The Raman spectra of water, heavy water and ice

      P K Narayanaswamy

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      The Raman spectra of water, heavy water D2O and ice have been studied using the λ2537 radiation of the mercury are as exciter. The shifts observed in water are Δν=60, 175, 475, 758, 1630, 3260, 3426, and 3610 cm.−1 Heavy water exhibits Raman bands at Δν=60, 176, 300–450, 1207, 2373, 2539 and 2670 cm.−1 The band at 60 cm.−1 is reported for the first time. A new Raman band is observed in the spectrum of ice extending from 213–310 cm.−1, the other Raman lines being at 52, 213·1, 3147, 3264 and 3347 cm.−1

    • The Raman spectra of cyclohexane, glycol and glycerine

      P K Narayanaswamy

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      The Raman spectra of cyclohexane, glycol and glycerine have been investigated with the λ 2536·5 radiation of the mercury arc as exciter. The wing in cyclohexane is found to extend up to ±95 cm.−1 from the exciting line. Five new lines are also observed in the spectrum. Glycol exhibits a wing of medium intensity extending up to ±130 cm.−1 and some new Raman lines are reported in its spectrum. Glycerine does not show any wing at all.

    • Influence of temperature on the Raman spectra of crystals - Part III. Barytes

      P K Narayanaswamy

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      The Raman spectrum of barytes excited by the λ2536 radiation of the mercury arc has been studied at a series of eight temperatures ranging from 85° to 923°K., and data furnished regarding the variations in frequency shift and the width of the principal Raman lines. With increasing temperature a definite decrease in frequency shift is observed, the rate of decrease being greater at higher temperatures. While at low temperatures the internal frequencies of the SO4 ion are clearly split up into distinct components, these tend to coalesce as the temperature is increased. The lattice oscillations are observed to be much more temperature sensitive than the internal oscillations of the SO4 group. The 89 cm.−1 lattice line and the 648 cm.−1 internal frequency are comparatively the least affected by temperature variations.

    • The α-β transformation in quartz

      P K Narayanaswamy

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      With the λ 2536·5 resonance radiation of the mercury arc as exciter, the Raman spectrum of β-quartz has been recorded for the first time. Due to the increased symmetry, the spectrum of β-quartz exhibits fewer Raman lines than α-quartz. The variations in frequency shift and width of the Raman lines after the α-β transition point are also found to differ markedly from the corresponding changes observed below the critical temperature.

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