Ultrasonic frequency shifts close to the first order and tricritical phase transitions in NH4Cl

Date

2001-12-01

Author

Yurtseven, Hasan Hamit
Bas, M

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This study examines our spectroscopic modifications of the Pippard relations using the ultrasonic frequencies of the q[110] and q[1 (1) over bar0] modes for the first order phase transition in NH4Cl. We also examine our relations using the ultrasonic frequencies of the q[110] mode for the tricritical phase transition in this crystal. From our plots of the specific heat C-p as a function of the frequency shifts (1/nu)(partial derivative nu/partial derivativeT)(p), we obtain that our spectroscopically modified Pippard relation considered here is satisfied for those phonon modes studied close to the first order and tricritical phase transitions in NH4Cl.

Subject Keywords

Pippard relations, Ultrasonic frequencies, NH4Cl

URI

https://hdl.handle.net/11511/57613

Journal

JOURNAL OF MOLECULAR STRUCTURE

DOI

https://doi.org/10.1016/s0022-2860(01)00628-7

Collections

Department of Physics, Article

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Ultrasonic frequencies calculated for the q[100] mode in the first-order, tricritical and the second-order phase transitions of NH4Cl Yurtseven, Hasan Hamit (2001-06-01) This study correlates the volume changes to the ultrasonic frequencies of the q[100] mode of NH4Cl for the first-order, tricritical and the second-order phase transitions in this crystal. Using these correlations we were able to calculate the ultrasonic frequencies of this mode at the pressures of 0, 0.6 and 1.1 kbar (first-order), 1.6 kbar (tricritical) and 2.15 kbar (second-order) by means of the volume change data from the literature. Our calculated frequencies are in good agreement with the observed dat...
Spectroscopic modifications of Pippard relations: first-order and second-order phase transitions in NH4Cl Yurtseven, Hasan Hamit (2001-01-01) In this study we introduce the spectroscopic modifications of Pippard relations and apply them to the disorder-induced Raman modes of NH4Cl in the first-order (P = 0) and second-order (2.8 kbar) phase regions in this crystalline system. We obtain Linear variations of the specific heat C-p with out observed frequency shifts [(l/nu)(partial derivative nu/partial derivativeT)(p)] of those Raman modes studied for the first-order and second-order phase transitions in NH4Cl. This will be discussed in detail.
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Ultrasonic frequencies correlated with the volume changes of the q[1(1)over-bar-0] mode for the first-order phase transition in NH4Cl Yurtseven, Hasan Hamit (Informa UK Limited, 2000-01-01) We correlate here by means of gamma-Gruneisen relations the volume changes with the ultrasonic frequencies of the q[1 (1) over bar 0] mode of NH4Cl for the first-order phase transition in this crystal. The ultrasonic frequencies were calculated by a method, which we have developed, using the length-change data from the literature at pressures of 0, 0.2, 0.3 and 0.6 kbar in the first-order phase region of NH4Cl.

Citation Formats

H. H. Yurtseven and M. Bas, “Ultrasonic frequency shifts close to the first order and tricritical phase transitions in NH4Cl,” JOURNAL OF MOLECULAR STRUCTURE, pp. 109–116, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57613.