Ultrasonic frequencies calculated for the q[100] mode in the first-order, tricritical and the second-order phase transitions of NH4Cl

Date

2001-06-01

Author

Yurtseven, Hasan Hamit

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

148
views

0
downloads

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 data for the phase region below the critical temperature T-C for the first-order, tricritical and the second-order phase transitions in NH4Cl. Above T-C our calculated frequencies do not agree satisfactorily for the q[100] mode and it is incapable of explaining the observed behaviour of NH4Cl. Our method of calculating the ultrasonic frequencies is presented.

Subject Keywords

Ultrasonic frequencies, Phase transitions, NH4Cl

URI

https://hdl.handle.net/11511/56383

Journal

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

DOI

https://doi.org/10.1016/s1386-1425(00)00464-9

Collections

Department of Physics, Article

Suggestions

OpenMETU
Core

Ultrasonic frequency shifts close to the first order and tricritical phase transitions in NH4Cl Yurtseven, Hasan Hamit; Bas, M (2001-12-01) 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 modifie...
Calculation of the ultrasonic frequencies of the q[110] mode for the first-order and tricritical phase transitions in NH4Cl Yurtseven, Hasan Hamit (2000-07-01) We study here the ultrasonic frequencies of the q[110] mode of NH4Cl, which we have correlated to the volume changes for the first-order and the tricritical phase transitions in this crystal. We calculated the ultrasonic frequencies of this mode by means of our correlations for the pressures of 0, 0.5 and 0.95 kbar in the first order, and for 1.5 kbar in the tricritical phase regions in NH4Cl using the observed data.
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.
Raman Frequencies Calculated at Various Pressures in Phase I of Benzene Tari, Ozlem; Yurtseven, Hasan Hamit (2013-04-01) We calculate in this study the pressure dependence of the frequencies for the Raman modes of A (A(g)), B (A(g), B-2g) and C (B-1g, B-3g) at constant temperatures of 274 and 294K (room temperature) for the solid phase I of benzene. Using the mode Gruneisen parameter of each lattice mode, which correlates the pressure dependence of the crystal volume and the frequency, the Raman frequencies of those modes are computed for phase I of benzene. Our results show that the Raman frequencies of the three lattice mod...
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, “Ultrasonic frequencies calculated for the q[100] mode in the first-order, tricritical and the second-order phase transitions of NH4Cl,” SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, pp. 1347–1359, 2001, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56383.