Calculation of the specific heat from the Raman frequency shifts close to the tricritical and second order phase transitions in NH4Cl

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 the Raman frequency shifts of this mode studied here, on the basis of an Ising model.


Calculation of the Raman Linewidths of Lattice Modes Close to the alpha-beta Transition in Quartz
Lider, Mustafa Cem; Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2012-12-01)
The Raman frequencies of the lattice modes (147 cm(-1) and 207 cm(-1)) are analyzed for the alpha-beta transition in quartz according to a power-law formula with the critical exponent by using the experimental data. The temperature dependence of the Raman frequency is associated with the order parameter (polarization P) for this transition in the quartz crystal.
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...
Calculation of the thermodynamic functions using a mean field model for the fluid-solid transition in nitrogen
AKAY, Özge; Yurtseven, Hasan Hamit (Romanian Academy - Revue Roumaine De Chimie, 2020-05-01)
Temperature and pressure dependence of the thermodynamic quantities are calculated using the Landau phenomenological model for the first order fluid-solid transition in nitrogen. This calculation is performed by fitting the phase line equation as derived from the mean field model to the observed T-P phase diagram of the fluid-solid transition in N2 from the literature. Our calculations show that the order parameter and the inverse susceptibility decrease whereas the entropy, heat capacity, thermal expansion...
Analysis of the Specific Heat in the Supercooled Solid Phase of Liquid Crystals
Kilit, Emel; Yurtseven, Hasan Hamit (Informa UK Limited, 2011-01-01)
The specific heat Cp is analyzed using the experimental data at various temperatures in the solid phase of cholesteryl myristate according to a power-law formula for the rapidly and slowly cooled solid in the stability limit. We also analyze the temperature dependence of the Cp using the experimental data for the supercooled solid phase of p-azoxyanisole in the stability limit and the stability temperatures are determined for both cholesteryl myristate and p-azoxyanisole.
Anisotropy of electrical resistivity and hole mobility in InTe single crystals
Parlak, Mehmet; Günal, İbrahim; Hasanlı, Nızamı (Wiley, 1996-01-01)
The temperature dependences of the electrical resistivity and Hall mobility of p-type InTe chain single crystals in parallel and perpendicular directions to c-axis have been investigated in the temperature range of 28-260 K. The high anisotropy between rho(parallel to) and rho(perpendicular to) which depends on temperature is attributed to high concentration of stacking faults due to weak interchain bonding. The mobility parallel to c-axis was found to vary with temperature as mu proportional to T-n where n...
Citation Formats
D. Kaya and H. H. Yurtseven, “Calculation of the specific heat from the Raman frequency shifts close to the tricritical and second order phase transitions in NH4Cl,” JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, pp. 861–865, 2007, Accessed: 00, 2020. [Online]. Available: