Ultrasonic frequencies correlated with the volume changes of the q[1(1)over-bar-0] mode for the first-order phase transition in NH4Cl

Date

2000-01-01

Author

Yurtseven, Hasan Hamit

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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.

Subject Keywords

Instrumentation, General Materials Science

URI

https://hdl.handle.net/11511/57709

Journal

PHASE TRANSITIONS

DOI

https://doi.org/10.1080/01411590008224543

Collections

Department of Physics, Article

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The mean field model with P-2 theta(2) coupling for the smectic A-smectic C* phase transition in liquid crystals Salihoglu, S; Yurtseven, Hasan Hamit; Giz, A; Kayisoglu, D; Konu, A (Informa UK Limited, 1998-01-01) Using mean field theory with a P(2)theta (2) coupling term in the free energy expansion, we calculate the polarization as a function of temperature for the smectic A-smectic C* phase transition in a liquid crystalline material. Our calculated polarization values are in good agreement with the experimental data.
Calculation of the specific heat for the first order, tricritical and second order phase transitions in NH4Cl Yurtseven, Hasan Hamit; Sherman, WF (Informa UK Limited, 1998-01-01) This work presents our calculation for the specific heat Cv under an Ising model that uses our Raman frequencies of the nu(7)TA (93 cm(-1)) and nu(5)TO (144 cm(-1)) modes for NH4Cl. The specific heat calculation has been performed for first-order (P = 0 kbar), tricritical (P = 1.6 kbar) and second-order (P = 2.8 kbar) phase transitions in the NH4Cl crystal. Our calculated Cv values are in good agreement with the experimentally observed Cp data from the literature for NH4Cl. This indicates that the NH4Cl cry...
The lambda-phase transition in NH4Br Yurtseven, Hasan Hamit; Sherman, WF (Informa UK Limited, 1996-01-01) This study gives the predicted frequencies for the Raman modes of v(7)TA(56 cm(-1)), v(5)LO(177 cm(-1)) and v(2)(1684 cm(-1)) of NH4Br at various temperatures for zero pressure across the lambda-phase transition in this crystal system. We calculate the Raman frequencies by means of a constant mode Gruneisen parameter for each mode across the lambda-phase change region of NH4Br.

Citation Formats

H. H. Yurtseven, “Ultrasonic frequencies correlated with the volume changes of the q[1(1)over-bar-0] mode for the first-order phase transition in NH4Cl,” PHASE TRANSITIONS, pp. 113–126, 2000, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57709.