Simulations of melting transitions

Results of recent theoretical and computer simulation studies of phase transitions in monolayer films of Lennard-Jones particles deposited on crystalline solids are discussed. DiflFerent approaches based on lattice gas and continuous space models of adsorbed films are considered. Some new results of Monte Carlo simulation study for melting and ordering in monolayer films formed on the (100) face of an fee crystal are presented and confronted with theoretical predictions. In particular, it is demonstrated that the inner structure of solid films and the mechanism of melting transition depend strongly on the effects due to the periodic variation of the gas - solid potential. 

Fig. 1.17 Computer simulation of melting, cooling, and the glass transition in silicon, showing results for four different quench rates on normalized density and volume per atom (from Argon and Demkowicz (2008) courtesy of TMS).

Batirev IG, Alavi A, Firmis MW, Deutsch T (1999) First principles calculations of the ideal cleavage energy of bulk niobimn(lll)/alpha-alumina(0001) interfaces. Phys Rev Let 82 1510-1513 Belonoshko AB (2001) Molecular dynamics simulation of phase transitions and melting in MgSi03 with the perovskite structine-cormnent. Am Mineral 86 193-194 Belonoshko AB, Dubrovinsky LS (1996) Molecular dynamics of NaCl(Bl and B20 and MgO(Bl) melting two-phase simulation. Am Mineral 81 303-316... 

Chaplot SL, Choudhury N (2001) Reply to cormnent on "Molecular dynamics simulation of phase transitions and melting in MgSiOs with the perovskite stracture". Am Mineial 86 195-196 Chokappa DK, Clancy P (1988) The influence of an interface in the promotion of melting. Molec Phys... 

We have also analyzed the influence of finite size effect on foe results presented here. We have repeated the simulations of melting of foe one-layer system using larger Monte Carlo boxes (two times and four times larger). There was a small size effect which made foe transition more localized in temperature (as compared to foe Fig.4) and slightly shifted towards... 

Fig. 17 B/E-p dependence of the critical temperatures of liquid-liquid demixing (dashed line) and the equilibrium melting temperatures of polymer crystals (solid line) for 512-mers at the critical concentrations, predicted by the mean-field lattice theory of polymer solutions. The triangles denote Tcol and the circles denote T cry both are obtained from the onset of phase transitions in the simulations of the dynamic cooling processes of a single 512-mer. The segments are drawn as a guide for the eye (Hu and Frenkel, unpublished results)...

Dynamics Simulations of the Thermal Glass Transition in Polymer Melts a-Relaxation Behavior. 

Simulation of the Glass Transition in Polymer Melts Extended Mode-Coupling Analysis. 

Remmele, R.L., Jr., J. Zhang, V. Dharmavaram, D. Balaban, M. Durst, A. Shoshi-taiskvili, and H. Rand. 2004. Scan-rate dependent melting transitions of interleukin-1 receptor (type II) elucidation of meaningful thermodynamic and kinetic parameters of aggregation acquired from DSC simulations (submitted for publication). 

Figure 6.33 Simulation results for melting only from the barrel surface, that is, one-dimensional melting. About 75% of the resin was melted at the end of the transition seotion. The bed height Y in this ease decreases essentially at the same rate that the channel depth decreases...

PMCS-4 with different ratios of trans- and cis-sequences in the backbone possess one and the same glass transition temperature, and the crystallinity degree is lower that for PDMS. While polymeric chain is enriched by trans-units, crystallinity increases [27], By methods of DSC, X-ray diffraction and thermooptical analysis, it have been detected that besides glass transition (Tg) and melting (Tmeit), polymers synthesized from monomers containing up to 95 - 100% of tram-isomers display a phase transition in the temperature range of 70 - 90°C, which is simulated as a transition from meso-morphous to isotropic state (Figure 2). 

Constant Pressure MD. The conventional MD technique uses a fixed size for the simulation box, that is, the calculation is performed under constant volume conditions. Using methods developed by Parrinello and Rahman and by Berendsen and coworkers, it is now possible to undertake constant pressure simulations by allowing cell dimensions to vary dnring the simulation. Detailed discussions are given in Referenced . The most obvious field of application of this technique is to the study of phase transitions, and useful applications have been reported to the study of melting and glass formation as discussed below. 

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