Application of the Generalized Ewald Method to a Molecular System

Fuchizaki, Kazuhiro

doi:10.1143/jpsj.79.024004

Cited by 4 publications

(1 citation statement)

References 19 publications

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“…represents a molecular form factor composed of the sum of the lth scattering center, whose position relative to the CM is denoted by p j l [37] (the 0th center is assumed to be at the CM), belonging to the jth molecule. The angular brackets in (2b) represent taking averages over ω 1 and ω 2 .…”

Section: Origin Of the Principal Peakmentioning

confidence: 99%

Structure of a molecular liquid GeI₄

Fuchizaki

Sakagami

Kohara

et al. 2016

J. Phys.: Condens. Matter

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A molecular liquid GeI4 is a candidate that undergoes a pressure-induced liquid-to-liquid phase transition. This study establishes the reference structure of the low-pressure liquid phase. Synchrotron x-ray diffraction measurements were carried out at several temperatures between the melting and the boiling points under ambient pressure. The molecule has regular tetrahedral symmetry, and the intramolecular Ge-I length of 2.51 Å is almost temperature-independent within the measured range. A reverse Monte Carlo (RMC) analysis is employed to find that the distribution of molecular centers remains self-similar against heating, and thus justifying the length-scaling method adopted in determining the density. The RMC analysis also reveals that the vertex-to-face orientation of the nearest molecules are not straightly aligned, but are inclined at about 20 degrees, thereby making the closest intermolecular I-I distance definitely shorter than the intramolecular one. The prepeak observed at ∼1 Å(-1) in the structural factor slightly shifts and increases in height with increasing temperature. The origin of the prepeak is clearly identified to be traces of the 111 diffraction peak in the crystalline state. The prepeak, assuming the residual spatial correlation between germanium sites in the densest direction, thus shifts toward lower wavenumbers with thermal expansion. The aspect that a relative reduction in molecular size associated with the volume expansion is responsible for the increase in the prepeak's height is confirmed by a simulation, in which the molecular size is changed.

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Section: Origin Of the Principal Peakmentioning

confidence: 99%

Structure of a molecular liquid GeI₄

Fuchizaki

Sakagami

Kohara

et al. 2016

J. Phys.: Condens. Matter

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Phase diagram of the modified Lennard-Jones system

Asano

Fuchizaki

2012

The Journal of Chemical Physics

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An investigation of the precise determination of melting temperature in the modified Lennard-Jones system under pressure-free conditions [Y. Asano and K. Fuchizaki, J. Phys. Soc. Jpn. 78, 055002 (2009)] was extended under finite-pressure conditions to obtain the phase diagram. The temperature and pressure of the triple point were estimated to be 0.61 ε∕k(B) and 0.0018(5) ε∕σ(3), and those of the critical point were 1.0709(19) ε∕k(B) and 0.1228(20) ε∕σ(3), where ε and σ are the Lennard-Jones parameters for energy and length scales, respectively, and k(B) is the Boltzmann constant. The potential used here has a finite attractive tail and does not suffer from cutoff problems. The potential can thus be a useful standard in examining statistical-mechanical problems in which different treatments for the tail would lead to different conclusions. The present phase diagram will then be a useful guide not only for equilibrium calculations but also for nonequilibrium problems such as discussions of the limits of phase (in)stability.

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Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30

Adidharma

Tan

2016

The Journal of Chemical Physics

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Canonical Monte Carlo simulations on face-centered cubic (FCC) and hexagonal closed packed (HCP) Lennard-Jones (LJ) solids are conducted at very low temperatures (0.10 ≤ T(∗) ≤ 1.20) and high densities (0.96 ≤ ρ(∗) ≤ 1.30). A simple and robust method is introduced to determine whether or not the cutoff distance used in the simulation is large enough to provide accurate thermodynamic properties, which enables us to distinguish the properties of FCC from that of HCP LJ solids with confidence, despite their close similarities. Free-energy expressions derived from the simulation results are also proposed, not only to describe the properties of those individual structures but also the FCC-liquid, FCC-vapor, and FCC-HCP solid phase equilibria.

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Application of the Generalized Ewald Method to a Molecular System

Cited by 4 publications

References 19 publications

Structure of a molecular liquid GeI₄

Structure of a molecular liquid GeI₄

Phase diagram of the modified Lennard-Jones system

Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30

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Application of the Generalized Ewald Method to a Molecular System

Cited by 4 publications

References 19 publications

Structure of a molecular liquid GeI4

Structure of a molecular liquid GeI4

Phase diagram of the modified Lennard-Jones system

Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30

Contact Info

Product

Resources

About

Structure of a molecular liquid GeI₄

Structure of a molecular liquid GeI₄