# Temperature and pressure dependence of$^3^5Cl\hspace{2mm} NQR$ in $NaCLO_3$ and $Ba\hspace{2mm}(ClO_3)_2 {\cdot}H_2O$

Krishnamoorthy, TV and Babu, PK and Ramakrishna, J (1991) Temperature and pressure dependence of$^3^5Cl\hspace{2mm} NQR$ in $NaCLO_3$ and $Ba\hspace{2mm}(ClO_3)_2 {\cdot}H_2O$. In: Journal of Molecular Structure, 249 (2-4). pp. 377-390.

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## Abstract

Pressure and temperature dependence of $^3^5Cl$ nuclear quadrupole resonance (NQR) has been investigated in $NaClO_3$ and $Ba\hspace{2mm}(ClO_3)_2{\cdot}H_2O$. NQR frequencies are measured in the temperature range 77–300 K and up to 5 kbar pressure. The torsional frequency of the $ClO_3$ pyramid and its variation with both pressure and temperature are evaluated from the NQR frequencies under the harmonic approximation. In general, the pressure effect on the internal motions is found to be less in $Ba\hspace{2mm}(ClO_3)_2{\cdot}H_2O$ compared to $NaClO_3$. When the samples are cooled to 77 K the pressure coeffecient of NQR frequency becomes nearly zero in sodium chlorate, whereas it retains a value of 6 kHz $kbar^{-1}$ in barium chlorate. This behaviour follows from the fact that at 77K, the torsional frequency in NaClO3 is unaffected by the application of pressure while it increases at the rate $12 cm^{-1}$ $kbar^{-1}$ in $Ba\hspace{2mm}(ClO_3)_2{\cdot}H_2O$.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Division of Physical & Mathematical Sciences > Physics 15 Sep 2006 19 Sep 2010 04:31 http://eprints.iisc.ernet.in/id/eprint/8453