Calculation of the specific heat for the first order, tricritical and second order phase transitions in NH4Cl

Date

1998-01-01

Author

Yurtseven, Hasan Hamit
Sherman, WF

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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 crystal can be adequately described in the lattice region by means of the Ising model studied here.

Subject Keywords

Instrumentation, General Materials Science

URI

https://hdl.handle.net/11511/55827

Journal

PHASE TRANSITIONS

DOI

https://doi.org/10.1080/01411599808228749

Collections

Department of Physics, Article

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Calculation of the specific heat from the Raman frequency shifts close to the tricritical and second order phase transitions in NH4Cl Kaya, D.; Yurtseven, Hasan Hamit (Elsevier BV, 2007-05-01) This study gives our calculation for the specific heat using our Raman frequency shifts of the v(5) (174 cm(-1)) mode close to the tricritical (P = 1.6 kbar) and second order (P = 2.8 kbar) phase transitions in NH4Cl. For this calculation we use as the values of the critical exponent for the specific heat, a = 0.11 (T < T-c and T > T-c) for the tricritical (T-c = 257.17 K), and a = 0.18 (T < T-c), a = 0.64 (T > T-c) for the second order (T-c = 268 K) phase transitions, which we deduce from our analysis of t...
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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 W. Sherman, “Calculation of the specific heat for the first order, tricritical and second order phase transitions in NH4Cl,” PHASE TRANSITIONS, pp. 399–412, 1998, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/55827.