Research

Research Interests

  • Molecular Simulation
  • Molecular and Statistical Thermodynamics

Overview

Molecular Simulations techniques such as molecular dynamics and Monte Carlo simulations are used in the development of new methods for determination of free energies and phase equilibria of different systems. Our group has been working on the development of a multi-scale modelling scheme for compound semiconductors which find wide range of applications in the fabrication of opto-electronic devices. Other areas of research include performing molecular simulations to determine the adsorption behaviour and phase equilibria of confined fluids; and to study the impact of different factors such as strength of wall-fluid interactions, on these fluids. Further, the group is also employing the molecular simulation approach to generate phase equilibria data which are required in the design and optimization of polymerization process equipment. We are also working on the development of efficient molecular simulation techniques for phase equlibira predictions. The development of a generic computional scheme for rational solvent design is also in progress.

Current Research

Phase behaviour of triangle well fluids in bulk phase and under confinement in slit pores

Fluids confined in porous materials have properties which are different from bulk phase. These properties enable the novel applications of these materials. Experiments at dimensions of the order of nanometers are difficult. This project involves the characterization and understanding of properties such as phase segregation, adsorption, etc., in pores of such dimensions using molecular simulation techniques. 

Computational schemes for rational solvent design

The group is also attempting to develop a computational scheme for rational solvent design to select the optimal solvent (or design a new solvent) for the extraction of a pharmaceutical intermediate synthesized using a biotransformation process. An additional step, whereby the cost-effective molecular simulation approach (the accuracy of this approach is limited only by that of the force field employed to model the interactions in the molecule) is used to verify the trends in the computer-aided molecular design results; has been introduced in the computational scheme. The molecular simulation techniques also allow us to gain molecular insights into the solvent extraction process.

Prediction of thermodynamic properties for industrially important polymerization systems using molecular simulations

In this project, we will attempt to predict the VLE data for pure component monomers and their mixtures with different reactants/products at the operating conditions of the process equipment. This data, necessary for the design and optimization of process equipment, is generally not available or only very limited data is available in literature. We are presently focusing our research on the polyethylene polymerization system.

Molecular simulation study of phase equilibria of molecular fluids

The development of efficient molecular simulation techniques for prediction of vapour-liquid equilibria is an on-going effort. We are studying molecular simulation methods to be applied to pure component and binary systems of model fluids as also molecular fluids.

Design of compound semiconductor alloys using molecular simulations

Simulation of solids provide a unique challenge because of the high densities involved which preclude use of any of the well established insertion/deletion methods used in the fluid phases. This provides an opportunity for the development of new methods to successfully measure the free energy of the solids and to improve the efficiency of the techniques used. Inter-atomic potential models are developed and investigated for applications of molecular simulation techniques to study solid fluid phase equilibria. Molecular simulation techniques are applied to determine the solubility diagrams for solid solutions, such as ternary and quaternary compound semiconductor alloys, and also to predict the structural properties, local composition and thermophysical properties of the above mentioned alloys. Compound semiconductor alloys have properties which are usefulfor the manufacture of optoelectronic devices. The application and continued development of java package called "etomica" (DAK group, University at Buffalo) for molecular simulations.

Compound semiconductors alloys are used in the manufacture of optoelectronic devices, such as high brightness Light Emitting Diodes and semiconductor laser diodes. The cost of development of these ternary and quaternary alloys into a marketable devices using only experimental research is very high. Using computer simulations in conjunction with experiments lower the costs involved in researching these alloys as simulations can be used to reduce the alternatives to the point where only the useful alloys can be subjected to experiments.

Multi-scale simulation of III-V compound semiconductors

This project envisages development of a novel multi-scale simulation scheme to design the III-V compound semiconductor alloys, which are used or have the potential to be used, in several applications such as devices for optical data-storage, fibre-optics communications, infra-red cameras, imaging sensors, specialty lasers and low power, high brightness lighting.

Molecular Simulation study of the miscibility behaviour and microstructure of compound semiconductor alloys

The work under this topic envisions a molecular simulation study of the miscibility behaviour and the microstructure in compound semiconductor alloys. The Tersoff potential model is the interatomic interaction potential for the InxGa1-xAs alloy system, which is selected as a representative example of these alloys. The alloy will be modelled for a range of compositions (considering x from zero to unity) and temperature from 100 K to the measured upper critical solution temperature. The bulk phase and thin films are both considered in the study. The microstructure is characterized by properties such as lattice constant and bond length, which are useful to measure as a way to connect to experiment and thereby, validate the model. The local composition as predicted by simulations can help in predicting the effect of microphase segregation that is difficult to quantify experimentally. The existence of even small microphases can have a disproportionate effect on the optoelectronic properties of these alloys. Monte Carlo simulations in the isothermal-isobaric semigrand ensemble are used for simulation purposes. InxGa1-xAs has been chosen due to its special properties, which enable its extensive use in fibre optic communications. Though this work is modelling the InxGa1-xAs alloy system, it can be easily be extended to other III-V and II-VI compound semiconductor alloys.