Calculation of the soft-mode frequency for the alpha - beta transition in quartz

The alpha - beta structural transition occurs in quartz at T-c = 846 K. The frequency of the soft mode associated with the volume increase, decreases with increasing temperature as the transition temperature is approached.


Calculation of the Raman frequency shifts for the alpha phase of solid oxygen
Yurtseven, Hasan Hamit (Elsevier BV, 2017-01-01)
We calculate in this study the Raman frequencies of the two librons and one vibron at various pressures at constant temperatures of 10 K and also at the temperatures of 6 and 18 K by using the volume data from the literature through the mode Gruneisen parameter for the a phase of oxygen.
Calculation of the heat capacity Cp from the temperature-induced and pressure-induced Raman frequency shifts for solid benzene, naphthalene and anthracene
Ozdemir, Hilal; Yurtseven, Hasan Hamit (Elsevier BV, 2019-02-01)
The heat capacity Cp is calculated from the temperature-induced and pressure-induced Raman frequency shifts by means of the mode Griineisen parameter for the I-II transition of solid benzene, naphthalene and anthracene. For this calculation, contributions to Cp are considered due to the six lattice modes of solid benzene, six librational modes of naphthalene and, six phonons and nine vibrons of anthracene with their mode Griineisen parameters at various temperature (P = 0) and pressures (T=300 K). Our calcu...
Calculation of the Raman frequency and linewidth of vibrons using anharmonic self energy model for the ε, δloc and δ phases in solid nitrogen
Akay, Ö.; Yurtseven, Hasan Hamit (Elsevier BV, 2020-10-01)
Temperature dependences of the Raman frequency shifts and linewidths of vibrons ν1, ν2 and ν22 are calculated from the anharmonic self energy in the ε, δloc (localized δ) and δ phases of solid nitrogen (P = 18.5 GPa). This is performed by fitting the expressions from the the anharmonic self energy to the experimental frequency and FWHM data for those vibrons from the literature. Our results show that the anharmonic self energy model can explain adequately the observed behavior of the Raman frequency and lin...
Characterization of chiral metamaterial sensor with high sensitivity
Dalgac, Sekip; BAKIR, MEHMET; KARADAĞ, FARUK; ÜNAL, EMİN; KARAASLAN, MUHARREM; Sabah, Cumali (Elsevier BV, 2020-02-01)
In this study, a chiral metamaterial sensor applications are created by placing asymmetrically two meander line front and back side of the substrate layer. Characterization of the dielectric constant, thickness and loss tangent have been performed both in simulation and experimental methods. Different Arlon type materials used for showing the effects of dielectric constant on transmission coefficient. Obtained bandwidths for characterization are greater than the similar studies which verifyies increased sen...
Optical properties of Tl2InGaS4 layered single crystal
Qasrawi, A. F.; Hasanlı, Nızamı (Elsevier BV, 2007-08-01)
The temperature dependence of the optical band gap of Tl2InGaS4 single crystal in the temperature region of 300-500 K and the room temperature refractive index, n(lambda), have been investigated. The absorption coefficient, which was calculated from the transmittance and reflectance spectra in the incident photon energy range of 2.28-2.48 eV, increased with increasing temperature. Consistently, the absorption edge shifts to lower energy values as temperature increases. The fundamental absorption edge corres...
Citation Formats
H. H. Yurtseven, “Calculation of the soft-mode frequency for the alpha - beta transition in quartz,” OPTIK, pp. 4470–4472, 2016, Accessed: 00, 2020. [Online]. Available: