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Classical Mechanics Electrodynamics
Statistical Mechanics
Molecular simulations
Stochastic problems in physics
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Dr. Prasanth P Jose,
Faculty of Physics
School of Basic Sciences
email: prasanth [at] iitmandi.ac.in
Research
Glass transition in low density model systems
When a liquid undergoes rapid cooling or compression, that is sufficiently fast to suppress crystallization, the liquid undergoes structural glass transition. The structural glass transition is characterized by large variation in density relaxation with small change in the thermodynamic control parameter, such as, density and temperature. This large variation in the relaxation properties occurs with small variation in the underlying structure of the system. This study look into role played by local density in relaxation from the simulations of glass forming binary Lennard-Jones and polymer model liquids. We compared the relaxation properties of the glass forming model liquid in higher density and lower density with variation in the temperature. At lower density the system phase separate at lower temperatures. By comparing relaxation properties in the phase separated region and at high density and we observe similarity in the properties of relaxation. We relate the observed relaxation properties to variation in the local density in the first coordination shell of the system.
Nearest neighbor distribution in a phase separated polymer system
Similarities between protein folding and granular jamming
Grains and glasses, widely different materials, arrest their motions upon decreasing temperature and external load, respectively, in common ways, leading to a universal jamming phase diagram conjecture. However, unified theories are lacking, mainly because of the disparate nature of the particle interactions. Here we demonstrate that folded proteins exhibit signatures common to both glassiness and jamming by using temperature- and force-unfolding molecular dynamics simulations.
Phase diagram of proteins
Force chains granular medium and proteins
Nature Communications 3, 1161 (2012)
Structure and dynamics of the semidilute polymer solution under steady shear
Semidilute polymer solution at equilibrim and under steady shear flow shows enhanced scattering of light. This project models a semidilute solution with system of chains made up of beads connected with springs. The long time brownian dynamics of this system under steady shear flow could reproduce the experimentally observed light scattering patterns, which shed light on the microscopic details of this phenomena.
J. Chem. Phys. 127, 114905 (2007)
J. Chem. Phys. 128, 224910 (2008)
Intra and inter chain contributions of the enhanced light scattering pattern
Dynamics of Liquid Crystals near Isotropic-Nematic phase transition
Isotropic (random orientation) to Nematic (orientationally ordered) phase transition in liquid crystals is a weak first order phase transition. The properties of relaxation of conserved and non-conserved variables, orientation, density etc., are studied using long time molecular dynamics simulations. The relaxation of the orientational order parameter shows slow down in the pretransition region.
J. Chem. Phys. 120, 11256 (2004)
J. Chem. Phys. 121 , 6978 (2004)
Phys. Rev. E 71, 030701(R) (2005)
Phys. Rev. Lett. 95,197801 (2005)
J. Chem. Phys. 125, 184901 (2006)
Phases of the Gay-Berne ellipsoids with aspect ratio 3
Non equilibrium relaxation through Montecarlo simulations
In this work density relaxation of one dimensional channel is modeled as random walkers that interact through excluded volume interaction (one excludes other from occupying the same site). The collective relaxation follows a stretched exponential relaxation in the isolated lattice.
J. Chem. Phys. 120, 8327 (2004)
Clustering of colloids under radiation pressure: A study using Brownian dynamics simulation,
Radiation can exert force on particle by scattering. This effect can be used to control clustering of particles in a solution. Brownian dynamics simulations used to models dynamics of particles in an optical trap.
