Toshiki Mima

Cell size dependence of orientational order of uniaxial liquid crystals in flat slit

In order to investigate the ordered structure of nematic liquid crystal molecules confined in a nanoslit, we carried out a classical molecular dynamics simulation of uniaxial prolate Gay–Berne particles in a flat, structureless slit at several temperatures. When the slit gap is so small that the system is not assumed as the bulk, particles in the slit possess orientationally ordered structures different from ones in the bulk. The weak spacial orientational correlation existed when the temperature corresponded to the isotropic phase in the bulk system. The first order isotropic–nematic phase transition was not clearly observed and the transitional phenomenon of the creation and annihilation of the uniaxial domains were observed. These results revealed that the ordered structure depends on the number of particles, in other words, cell size, and that the system with 100,000 or more particles gives reasonable results of an infinitely wide slit. The number of particles is converted into up to 220 particles of the length of the base.

Molecular dynamics simulation of time-irreversibility of stationary heat flux

Molecular dynamics simulations are carried out to monitor heat flux directly, in both forward process and time-reversed process. Two weighted Nosé–Hoover thermostats, whose temperatures are different independently, are attached to a Stillinger–Weber fcc crystal confined by reflective walls. With increasing temperature difference, phase-space collapse rate in the forward process decreased and the irreversibility of heat flux appeared earlier in time-reversed process. The irreversibility appeared earlier, with decreasing numbers of significant digits. Nevertheless, the values of phase-space collapse rate were almost same.

Erratum: Cell size dependence of orientational order of uniaxial liquid crystals in flat slit (Molecular Simulation (2008) 34:8 (761-773))

In the paper entitled Cell size dependence of orientational order of uniaxial liquid crystals in flat slit, Molecular Simulation 34 (8), (July 2008), pp. 761–773, we reported the ordered state of the Gay–Berne (GB) ellipsoids as the nematic liquid crystals in the flat nanoslit. We have since discovered errors in the calculations of the twodimensional self-diffusion coefficients (2DSDCs), D2D, from the two-dimensional mean square displacements (2DMSDs). In this erratum, the 2DSDCs are corrected in Table 1, where N is the number of particles and T is the temperature. For ðN; TÞ 1⁄4 ð100;000; 1:00Þ, the 2DSDC is recalculated from the 2DMSD using the least-squares method. For the other conditions, the 2DSDCs are corrected to be double their original values. Because the 2DSDCs at T 1⁄4 1:00 are even smaller by one digit than the ones at the temperature of 1.05 or greater, we consider that the conclusion reported in the original paper is not affected; the GB ellipsoids are in the solid phase at T 1⁄4 1:00, while they possess a fluidity at T

Phase diagram of Lennard-Jones fluid confined in slit pores

1:05.