Calculation of the free energies for the solid phases of ammonium halides

Salihoglu, S.
Yurtseven, Hasan Hamit
Karacali, H.
Using mean field theory, we calculate the free energies of the solid phases of ammonium halides. The temperature and pressure dependences of the free energies are obtained using experimental phase diagrams of the ammonium halides. From these dependences, we calculate numerically the specific heat as a function of temperature for the solid I-liquid, solid II-liquid and solid I-solid II transitions in the ammonium halides, in particular for NH4Cl. The critical behaviour of some other thermodynamic quantities is also predicted from the mean field theory.


Calculation of the specific heat for the first order phase transition in NH4Br
Yurtseven, Hasan Hamit; Sherman, WF (World Scientific Pub Co Pte Lt, 1998-11-01)
We calculate in this work the specific heat C-VI using the predictions of an Ising model for the NH4Br crystal (T-C = 234 K, P = 0). Our calculated C-VI values are in good agreement with the experimentally observed C-p data from the literature. This shows that the observed behavior of NH4Br can be described adequately in the lattice region under an Ising model studied here.
Short-range correlations in a one-dimensional electron gas
Tas, M; Tomak, Mehmet (American Physical Society (APS), 2003-06-15)
We use the Singwi-Sjolander-Tosi-Land (SSTL) approximation to investigate the short-range correlations in a one-dimensional electron gas. We find out that the SSTL approximation satisfies the compressibility sum rule somewhat better than the more widely used Singwi-Tosi-Land-Sjolander approximation in the case of a one-dimensional electron gas.
Study of trapping and recombination centres in Tl2InGaTe4 chain crystals by dark electrical conductivity and photoconductivity measurements
QASRAWI, ATEF FAYEZ HASAN; Hasanlı, Nızamı (Informa UK Limited, 2007-01-01)
Dark electrical conductivity and photoconductivity of Tl2InGaTe4 single crystals have been measured and analyzed in the temperature region 100-300 K. The dark electrical conductivity measurements revealed an intrinsic- or extrinsic-type of conductivity above or below 210 K, respectively. From intrinsic conductivity data analysis, the energy band gap of Tl2InGaTe4 crystals was determined as 0.85 eV. In the extrinsic region, the dark conductivity arises from a donor energy level located at 0.30 eV below the c...
Determination of trapping parameters in n-Ga4Se3S by thermally stimulated current measurements
Goksen, K.; Hasanlı, Nızamı (Informa UK Limited, 2009-01-01)
Thermally stimulated current (TSC) measurements were carried out on as-grown n-Ga4Se3S layered crystals in the temperature range 10-300 K. The experimental data were analysed by using different heating rates, initial rise, curve fitting and isothermal decay methods. The results of the analysis showed good agreement with each other. The measurements revealed the presence of one trapping level with activation energy of 23 meV. The corresponding capture cross-section and concentration of traps were found to be...
Optoelectronic properties of Tl3InSe4 single crystals
QASRAWI, ATEF FAYEZ HASAN; Hasanlı, Nızamı (Informa UK Limited, 2010-01-01)
The crystal structure, temperature-dependent electrical conductivity, Hall coefficient, current-voltage characteristics, absorption spectra and temperature- and illumination-dependent photoconductivity of Tl3InSe4 single crystals were investigated. Tl3InSe4 crystallises in a body-centred lattice with tetragonal symmetry and belongs to the space group [image omitted]. The crystals are extrinsic p-type semiconductors and exhibit a conductivity conversion from p- to n-type at a critical temperature, Tc, of 283...
Citation Formats
S. Salihoglu, H. H. Yurtseven, and H. Karacali, “Calculation of the free energies for the solid phases of ammonium halides,” PHILOSOPHICAL MAGAZINE, pp. 2371–2387, 2007, Accessed: 00, 2020. [Online]. Available: