Spectroscopic intensities as measures of order parameter close to order-disorder transitions

The infrared and Raman intensities can be related to the order parameter close to order-disorder phase transitions in crystal systems. In the present study this relationship has been obtained and compared with our experimental results for ammonium halides. Our predictions give satisfactory agreement with the observations in these crystals. It is proposed that the FTIR techniques can be appropriately used to evaluating the order parameter in various crystal systems.
Mikrochimica Acta


Raman bandwidths calculated for the librational ( a -phase) and internal (8, d loc and d phases) modes in solid N 2 using pseudospin-phonon coupling (PS) and energy-fluctuation (EF) models
Yurtseven, Hasan Hamit (Elsevier BV, 2020-10-01)
This study gives the calculation of the Raman bandwidths using the models of the pseudospin-phonon coupling (PS) and energy fluctuation (EF) where the Raman frequency calculated from the molecular field theory, is considered as the order parameter close to the phase transitions in nitrogen. In particular, we study the temperature dependence of the Raman bandwidths and frequency shifts of the Eg librational mode (zero pressure) and the internal modes of and (at various pressures) for the solid nitrogen by ...
Resonant frequency shifts related to the elastic constants near the alpha-beta transition in quartz
Yurtseven, Hasan Hamit (Elsevier BV, 2019-03-05)
The resonant frequency shifts of vibrational modes are related to the elastic constants at various temperatures for the alpha-beta transition in quartz (T-c = 573.0 degrees C for alpha-quartz and 574.3 degrees C for beta-quartz). This correlation is constructed on the basis of the spectroscopic modifications of the Pippard relations near the alpha-beta transition in quartz by using the observed data from the literature.
Vibrational frequencies studied as a function of pressure in phase II of solid benzene
Yurtseven, Hasan Hamit; Kilit, E. (Elsevier BV, 2011-05-03)
The pressure dependence of the vibrational frequencies of six Raman modes is analyzed in phase II of solid benzene. The frequency shifts 1/nu(partial derivative nu/partial derivative P)(T) of those Raman modes are deduced from this analysis and they are related to the isothermal compressibility kappa(T)= -(1/V)(partial derivative V/partial derivative P)(T) through a constant isothermal mode Gruneisen parameter gamma(T) in phase II of solid benzene. The kappa(T) values predicted here are compared with the ka...
Spectroscopic measurements of electron temperature and electron density in electron beam plasma generator based on collisional radiative model
Goktas, H.; Demir, A.; Kacar, E.; Hegazy, H.; Turan, Raşit; Oke, G.; Seyhan, A. (Informa UK Limited, 2007-01-01)
The current work describes a spectroscopic method for determining the electron temperature and electron density in an electron beam generator using argon spectral lines based on a collisional radiative model. Neutral and first-ionized Ar lines emitted from the electron beam generator are studied experimentally. A collisional radiative code was developed to simulate the Ar (I) and Ar (II) spectral emission and to compare the results with the experimental data for electron density and temperature determinatio...
ERGUCYENER, C; AYGUN, S; Ataman, Osman Yavuz; TEMIZER, A (1988-01-01)
Mercury speciation in aqueous solutions containing inorganic mercury and methylmercury has been demonstrated using electrochemical separation prior to determination by cold-vapour atomic absorption spectrometry. Approximately 95% of the inorganic mercury was electro-deposited on a Pt electrode at –0.1 V, whereas for methylmercury –0.2 V or even more negative potentials were required. Organic mercury was determined by NaBH4 reduction after electrochemical separation. Inorganic mercury was determined in the o...
Citation Formats
H. H. Yurtseven, “Spectroscopic intensities as measures of order parameter close to order-disorder transitions,” Mikrochimica Acta, pp. 125–127, 1988, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57316.