Second virial coefficient of rod-shaped molecules and molecular dynamics simulations of the isotropic phase

Abstract

The second virial coefficient, B(2) is computed of linear rigid rods composed of m equally spaced sites interacting with sites on other rods via the hard-sphere or Weeks-Chandler-Andersen (WCA) pair potentials. The dependence of B(2) on a wide range of separation distance between the sites L and m for both types of potential is computed. Molecular dynamics simulations were carried out of the thermodynamic, static, and percolation properties of the WCA rigid rods in the isotropic phase as a function of rod number density ρ. Simple scaling relationships are discovered between thermodynamic and other static properties as a function of ρ and m, which extend well into the semidilute density range. The percolation threshold distance (PTD) between the centers of mass of the rods complies well with a mean-field random orientation approximation from low density well into the semidilute regime. The corresponding site-site PTD proved more problematic to represent by simple functions, but at high rod density, scales better with the number of sites density rather than the rod number density.

Heating leads to liquid-crystal and crystalline order in a two-temperature active fluid of rods

“…where d m is the shortest distance between two spherocylinders that determines their relative orientation and interacting force [56][57][58]. Note that representing spherocylinder by a line of interacting spheres can also be used to study various LC phases [59].…”