Calculation of the Raman Linewidths of Lattice Modes Close to the alpha-beta Transition in Quartz

Lider, Mustafa Cem
Yurtseven, Hasan Hamit
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.


Analysis of the Raman Frequency Shifts for the Lattice Modes and Vibrons Related to the Thermodynamic Quantities in the eta Phase of Solid Nitrogen
Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2013-08-01)
The thermodynamic quantities of the isothermal compressibility, thermal expansion and the specific heat are calculated here as a function of pressure by using the observed Raman frequencies of the lattice modes and vibrons in the. phase of solid nitrogen. The Pippard relations and their spectroscopic modifications are constructed, and the slope dP/dT is deduced from the Raman frequency shifts in this phase of N-2. It is shown that the thermodynamic quantities can be predicted from the Raman frequency shifts...
Critical Behaviour of the Heat Capacity Near the alpha-beta Phase Transition in Quartz
Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2013-04-01)
The alpha-beta transition ( T-Q = 578 degrees C) is studied in quartz by analyzing the experimental heat capacity C-p data taken from the literature, using a power-law formula. Values of the critical exponent alpha for C-p are extracted below and above T-Q, which describe the alpha-beta transition as a second order transition in quartz. The alpha values obtained here are compared with the predictions of the theoretical models.
Calculation of the Specific Heat Close to Phase Transition in S-triazine
KURT, MUSTAFA; Yurtseven, Hasan Hamit (Walter de Gruyter GmbH, 2009-01-01)
The specific heat C-V as a function of temperature has been calculated using the quasi-harmonic and mean field approximation for s-triazine close to the transition temperature (T-C=198 K). Using the parameters for the shear strain angle (order parameter) fitted to the observed Raman frequencies of the four bands, the specific heat C-V is calculated from the free energy of s-triazine.
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...
Calculation of the Spontaneous Polarization and the Dielectric Constant for the Ferroelectric N(CH3)(4)HSO4 Using the Mean Field Model
Yurtseven, Hasan Hamit; KARACALİ, HUSEYİN (Walter de Gruyter GmbH, 2017-10-01)
The temperature dependences of the spontaneous polarization and the dielectric constant (susceptibility) are calculated using themean fieldmodel for the ferroelectric N(CH3)(4)HSO4. Expressions derived from the mean fieldmodel for the spontaneous polarization and the inverse susceptibility are fitted to the experimental data from the literature. The fitting parameters in the expansion of the free energy in terms of the spontaneous polarization are determined within the temperature intervals in the ferroelec...
Citation Formats
M. C. Lider and H. H. Yurtseven, “Calculation of the Raman Linewidths of Lattice Modes Close to the alpha-beta Transition in Quartz,” HIGH TEMPERATURE MATERIALS AND PROCESSES, pp. 741–747, 2012, Accessed: 00, 2020. [Online]. Available: