Monte Carlo Studies of the Orientational Order-Disorder Phase Transition in Solid Ammonium Chloride
| dc.creator | Topper, Robert Q. | |
| dc.creator | Freeman, David L. | |
| dc.date | 1994-03-08 | |
| dc.date | 1994-03-11 | |
| dc.date.accessioned | 2026-07-07T08:58:33Z | |
| dc.date.available | 2026-07-07T08:58:33Z | |
| dc.description | Monte Carlo methods are used to study the phase transition in ammonium chloride from the orientationally ordered $δ$ phase to the orientationally disordered $γ$ phase. An effective pair potential is used to model the interaction between ions. Thermodynamic properties are computed in the canonical and isothermal-isobaric ensembles. Each ammonium ion is treated as a rigidly rotating body and the lattice is fixed in the low-temperature CsCl geometry. A simple extension of the Metropolis Monte Carlo method is used to overcome quasiergodicity in the rotational sampling. In the constant-$NVT$ calculations the lattice is held rigid; in the constant-$NpT$ calculations the lattice parameter is allowed to fluctuate. In both ensembles the order parameter rapidly falls to zero in the range (200 - 250)K, suggesting that the model disorders at a temperature in fair agreement with the experimental disordering temperature (243K). Peaks in the heat capacity and thermal expansivity curves are also found in the same temperature range. | |
| dc.description | submitted to Journal of Chemical Physics | |
| dc.identifier | https://arxiv.org/abs/chem-ph/9403002 | |
| dc.identifier | http://arxiv.org/abs/chem-ph/9403002 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/147369 | |
| dc.subject | Chemical Physics | |
| dc.title | Monte Carlo Studies of the Orientational Order-Disorder Phase Transition in Solid Ammonium Chloride | |
| dc.type | text |