A phase diagram for ammonium halides

Abstract

In this study we have developed a mean field model to obtain the phase diagrams for m C 1 and NI&Br. The phase diagrams obtained from our macroscopic theory are in good agreement with those obtained experimentally.

Calculation of the specific heat close to the multicritical and second order phase regions in ND4Cl

“…In the disordered (D) b phase all the NH 4 + tetrahedra are randomly distributed. All of these phases have been given in the generalised phase diagrams obtained experimentally [14][15][16][17] and those obtained theoretically [18][19][20][21][22] for ammonium halides. Figure 1 shows a master phase diagram obtained experimentally for ammonium and deutero-ammonium halides by Leung et al [16].…”

Analysis of the Raman frequencies of a lattice mode in NH4Cl close to the tricritical and second order phase transitions

“…Apart from those experimental studies regarding the phase diagrams in ammonium halides, some theoretical phase diagrams in these crystalline systems have been obtained [11][12][13]. We have also obtained using the mean field theory P-T phase diagram of ammonium halides [14] and T-X Br phase diagram of NH 4 Br x Cl 1 À x system [15]. Among various experimental techniques used to study the first order, tricritical, and the second order phase transitions in NH 4 Cl, the Raman spectroscopic technique in particular has been used widely as reported in the literature.…”

Calculation of a generalised smectic–hexatic phase diagram in liquid crystals

“…Using the mean field theory, we have calculated P-T [27,28] and T-X [29] phase diagrams in ammonium halides, ammonia [30], ice [31][32][33], and regarding the liquid crystals phase diagrams near the nematic-Sm A-Sm C (NAC) [34,35] and nematic-Sm A-Sm C* (NAC*) [36] point in our earlier studies.…”