Anubha Jaiswal | Searcharxiv

arXiv2014

Integral Equation Theory for Pair Correlation Functions in a Crystal

A method for calculating pair correlation functions in a crystal is developed. The method is based on separating the one- and two- particle correlation functions into the symmetry conserving and the symmetry broken parts. The conserving parts are calculated using the integral equation theory of homogeneous fluids. The symmetry broken part of the direct pair correlation function is calculated from a series written in powers of order parameters and that of the total pair correlation function from the Ornstein- Zernike equation. The results found for a two-dimensional hexagonal lattice show that the method provides accurate and detailed informations about the pair correlation functions in a crystal.

cond-mat.soft↗

arXiv2012

Freezing of a two dimensional fluid in to a crystalline phase : Density functional approach

A free-energy functional for a crystal proposed by Singh and Singh (Europhys. Lett. {\bf {88}}, 16005 (2009)) and which contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the crystallization of a two-dimensional fluid. The results found for fluids interacting via the inverse power potential $ u(r)= ε(σ/{r})^{n} $ for n= 3, 6 and 12 are in good agreement with experimental and simulation results. The contribution made by the symmetry broken part to the grand thermodynamic potential at the freezing point is found to increase with the softness of the potential. Our results explain why the Ramakrishnan-Yussouff (Phys. Rev. B {\bf 19}, 2775 (1979)) free-energy functional gave good account of freezing transitions of hard-core potentials but failed for potentials that have soft core and/or attractive tail.

cond-mat.soft↗