Program

P.64 -- Poster, NCTP-42

Date: Wednesday, 2 August 2017

Time: 08h30 - 10h00

Computer simulation of phase separation in 2D binary Lennard-Jones system.

Truong Hoa Thien (1), Vo Van Hoang (2), Nguyen Hoang Giang (2), Duong Thi Nhu Tranh (2)

(1) Department of Physics, College of Natural Sciences, Can Tho University (2) HochiMinh City Univ. of Technology, Vietnam National University – Ho Chi Minh City .

In this study, we present the microphase separation of two-dimensional (2D) binary Lennard-Jones system studied via molecular dynamics (MD) simulations. Models are cooled from liquid to glassy state in order to see the onset of phase separation. Models contain 8100 particles with identical size and interaction parameters $\sigma_{11}$, $\sigma_{12}$, $\sigma_{22}$, $\varepsilon_{11}$, but different $\varepsilon_{12}$, $\varepsilon_{22}$, interacted via Lennard – Jones potential of binary systems introduced by Kob-Andersen [1]: U(r) = 4{\varepsilon _{ij}}\left[ {{{\left( {\frac{{{\sigma _{ij}}}}{r}} \right)}^{12}} - {{\left( {\frac{{{\sigma _{ij}}}}{r}} \right)}^6}} \right] Dependence of various thermodynamic properties on different ratios $\varepsilon_{12}/\varepsilon_{22}$ is analyzed in details via radial distribution function (RDF), temperature dependence of total energy and mean cluster size. Microphase separation is monitored via 2D visualization of atomic configurations at various temperatures upon cooling from the melt using VMD software. We find that the speed of microphase separation process and cluster shapes depend on the ratio $\varepsilon_{12}/\varepsilon_{22}$ . The appearance of stripe patterns occurs when $\varepsilon_{12}$ is larger than $\varepsilon_{22}$ (the ratio $\varepsilon_{12}/\varepsilon_{22}$ is larger than 1) and the separation process is difficult to observe. In contrast, the bubble phases are characteristic of systems with $\varepsilon_{12}$ is smaller than $\varepsilon_{22}$ (the ratio $\varepsilon_{12}/\varepsilon_{22}$ is smaller than 1) so it is easy to observe the microphase separation process.

Presenter: Duong Thi Nhu Tranh