Analysis of the Raman intensities near the phase transitions in ammonium halides

This study concentrates on the temperature dependence of the Raman intensities for the lattice modes in ammonium halides (NH4Cl and NH4Br) close to phase transitions, We predict their intensities using the results of a shell model for the Raman polarizability within the framework of an Ising pseudospin-phonon coupled model.


Temperature dependence of the damping constant and the order parameter close to the lambda phase transitions in ammonium halides
Yurtseven, Hasan Hamit (Elsevier BV, 2006-10-01)
This study gives our calculation for the damping constant, using the expressions derived for an Ising pseudospin-phonon coupled system in the ammonium halides (NH4Cl and NH4Br). For this calculation of the damping constant, we use the temperature dependence of the order parameter calculated from the molecular field theory. We predict here the damping constants for the v(5) (174 cm(-1)) and v(5) (177 cm(-1)) Raman modes of NH4Cl and NH4Br, respectively, below T-lambda and compare them with our observed bandw...
Calculation of the Raman frequencies of the translational mode in ammonia solid II
Yurtseven, Hasan Hamit (Elsevier BV, 2003-03-01)
We report here our calculated Raman frequencies of the translational mode as a function of temperature for the. fixed pressures of 3.65, 5.02 and 6.57 kbars in the ammonia solid II. They were calculated by means of our Gruneisen relation using the volume data from the literature for all the pressures indicated within the temperature regions close to the melting point in this system. Our calculated frequencies are in very-good agreement with those observed experimentally for this translational mode of the am...
Quantum chemical studies on some seleanaphthalene derivatives
Türker, Burhan Lemi (Elsevier BV, 2005-04-01)
Quantum chemical studies on certain selenanaphthalene derivatives (having a keto or enol group and also Se atom in five- or six-membered ring system fused with naphthalene moiety) have been carried out using PM3 method at the level of restricted Hartree-Fock approach. The aquated systems have also been considered.
2-D analysis of Ge implanted SiO(2) surfaces by laser-induced breakdown spectroscopy
Yalcin, Serife; Oerer, Sabiha; Turan, Raşit (Elsevier BV, 2008-10-01)
2-D elemental distribution of Ge in silicon oxide substrates with differing implantation doses of between 3x10(16) cm(-2) and 1.5x10(17) cm(-2) has been investigated by Laser-induced Breakdown Spectroscopy (LIBS). Spectral emission intensity has been optimized with respect to time, crater size, ablation depth and laser energy. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) coupled with Energy-Dispersive X-Ray Spectroscopy (EDX) have been utilized to obtain crater depth, morphology and ...
Development of sensitive analytical methods for the determination of thallium at trace levels by slotted quartz tube flame atomic absorption spectrometry
Ari, Betul; BAKIRDERE, Sezgin; Ataman, Osman Yavuz (Elsevier BV, 2020-09-01)
A simple, sensitive and economical technique is needed for the determination of thallium and this study demonstrates the different analytical strategies were developed using atomic absorption spectrometry (AAS). In order to improve the sensitivity of flame atomic absorption spectrometry (FAAS), a basic slotted quartz tube (SQT) was used for the thallium determination. In the first strategy, mixing propanol (100 mu L) and Tl standard solution (500 mu L) under the optimum conditions, namely solvent assisted S...
Citation Formats
H. H. Yurtseven, “Analysis of the Raman intensities near the phase transitions in ammonium halides,” SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, pp. 862–868, 2008, Accessed: 00, 2020. [Online]. Available: