A phase diagram for ammonium iodide

Salihoglu, S
Tari, O
Yurtseven, Hasan Hamit
We obtain here a phase diagram of NH4I including the phases 11, 111 and IV in this crystalline system using the mean field theory. We fit our calculated phase line equations to the experimentally observed data for NH4I There is a good agreement between our calculated and observed phase diagram.


Thermal lattice scattering mobility and carrier effective mass in intrinsic Tl2InGaTe4 single crystals
Qasrawi, A. F.; Hasanlı, Nızamı (IOP Publishing, 2007-04-18)
Systematic structural, dark electrical resistivity and Hall coefficient measurements have been carried out on n- type Tl2InGaTe4 single crystals. The data from x- ray powder diffraction allowed determination of the tetragonal unit cell lattice parameters. Analysis of the electrical resistivity and carrier concentration, which was recorded in the temperature range 210 - 350 K, reveals the intrinsic type of conduction with an average energy band gap of 0.85 eV. The temperature- dependent Hall mobility was obs...
Below and above bandgap excited photoluminescence in Tl4InGa3S8 layered single crystals
Goksen, K.; Hasanlı, Nızamı (IOP Publishing, 2007-11-14)
Photoluminescence (PL) spectra of Tl4InGa3S8 layered single crystals grown by the Bridgman method have been studied in the 550-710 nm wavelength and 80 300 K temperature ranges with below bandgap excitation (lambda(exc) = 532 nm), and in the 420-600 nm wavelength and 30-300 K temperature ranges with above bandgap excitation (lambda(exc) = 325 nm). The broad emission bands centered at 580 nm (2.14 eV) and 496 nm (2.49 eV) were observed at T = 80 and 30 K for below and above bandgap excitation processes, resp...
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...
Atomic and electronic structure of Bi/GaAs(001)-alpha 2(2x4)
Usanmaz, D.; ÇAKMAK, MELEK; Ellialtıoğlu, Süleyman Şinasi (IOP Publishing, 2008-07-02)
We report an ab initio pseudopotential calculation for the atomic and electronic structure of Bi/GaAs(001)-alpha 2(2 x 4). Three structural models with Bi coverages of Theta = 1/4 are considered, containing one Bi dimer or two Bi-As mixed dimers. According to our calculations for this coverage, the atomic model of the Bi/GaAs(001)-(2 x 4) reconstruction is similar to the alpha 2 structure of the clean GaAs(001)-(2 x 4) surface in which the top As dimer is replaced by a Bi dimer. This result is in agreement ...
Composition-tuned band gap energy and refractive index in GaSxSe1-x layered mixed crystals
IŞIK, MEHMET; Hasanlı, Nızamı (Elsevier BV, 2017-04-01)
Transmission and reflection measurements on GaSxSe1-x mixed crystals (0 <= x <= 1) were carried out in the 400-1000 nm spectral range. Band gap energies of the studied crystals were obtained using the derivative spectra of transmittance and reflectance. The compositional dependence of band gap energy revealed that as sulfur (selenium) composition is increased (decreased) in the mixed crystals, band gap energy increases quadratically from 1.99 eV (GaSe) to 2.55 eV (GaS). Spectral dependencies of refractive i...
Citation Formats
S. Salihoglu, O. Tari, and H. H. Yurtseven, “A phase diagram for ammonium iodide,” MATERIALS CHEMISTRY AND PHYSICS, pp. 339–342, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56163.