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Research interests
My research interests are in the field of Theoretical Physics,
Dielectric relaxation and Theoretical Chemistry in particular:
I am interested
in both experimental and theoretical research.
My interests are not limited to the above-mentioned areas and I
am eager to pursue new directions and concepts, which are most promising and
profitable for today. I am always open to interesting ideas, new collaboration
and job opportunities.
Brief summary of my research activities
1) Designing
of Microwave components using Finite Element Method :
The
study of electromagnetic propagation through various guiding structures and
devices has got great significance in development of microwave communication
network and technology. However, in physical development of the guiding
structures, there is always a possibility of occurrence of certain
irregularities in these guiding structures. The main stress of our activities
is on Numerical methods and development of programs combining these methods to
achieve some objective. Finite Element Method (FEM) is one such procedure,
which is useful in different branch of Science and Engineering, for the
approximate solution of differential equation. FEM has the main advantage that
it can be used for any complicated geometry with irregular shape, and that it
is also useful for inhomogeneous and anisotropic media. We have developed our
own Finite Element Method Program in Turbo-Basic. The development of FEM
involves numerical integration, use of mapping functions, derivative
calculation, matrix manipulation like finding eigenvalues and solving set of
simultaneous equations. Special storage and evaluation ideas are to be used
because large size matrices are involved in process. FEM program developed
requires general description of the geometry and material properties. It shows graphically
the structure on the screen when needed. It generates the detailed data
required for further processing. It automatically divides the structure into
elements. For different steps in FEM, separate subroutines are used. The method used for the solution of the
eigenvalue equation is Subspace iteration method, which is combination of
Jacobi and Strum sequence check method. The developed FEM program has been used
to study problems of Electrodynamics for the solution of Maxwell's equations.
It involves the study of the effect of discontinuities on electromagnetic
propagation through waveguides and resonator.
Please see List of
Publication
2) Dielectric Relaxation study using Time Domain
Reflectometry technique :
Dielectric
relaxation spectroscopy probes the interaction of macroscopic sample with a
time dependent electric field. The observed dielectric polarization yields
information on structural aspects and dynamical processes which is only partly
accessible with other methods. The dielectric relaxation behavior of liquid
mixtures has gained increasing interest in recent years. For pure liquids and
liquid mixtures at ambient temperature, dynamical processes in the time scale
of pico-to-nano seconds arise from the orientation of molecular dipole moment,
from kinetic processes involved with intermolecular hydrogen bonding. The
dielectric properties of solutions have important effect on charge transport,
chemical specification and various thermodynamic properties of solutions. An
increasing need for dielectric data, characterizing the interaction of
materials with microwaves also arises from emerging technical applications such
as heating, moisture sensors and process control. We have used the Time Domain Reflectometry
(TDR) to find the dielectric properties such as static permittivity,
permittivity at high frequency and relaxation time, of binary and ternary
mixtures of polar liquids, with the help of a storage oscilloscope having GPIB
interfacing card. This time domain data is converted in frequency domain using
Fourier transformation, which in turn, is used to calculate reflection
coefficient. Finally, by using Least-squares fit method the dielectric
parameters are obtained with assumption of different models such as Debye,
Havriliak-Nigami model, Cole-Davidson, Cole-Cole etc. Using these values other
parameters such as excess permittivity, excess inverse relaxation time,
Kirkwood correlation factor, Bruggeman factor, Thermodynamic parameters are
also obtained. The computer programs are developed in TURBO-BASIC for the Time
Domain Reflectometry (TDR) experiment.
Please see List of
Publication.
3) Computer simulation of catalytic reactions :
Heterogeneous
catalysis is a field of considerable interest for its practical application. In
all heterogeneous chemistry systems, the geometry and structure of the
environment in which the chemical process takes place plays a key role in
determining the reaction rate and its performance. One of the most challenging
problems in surface science is the understanding of the effect of surface
roughness on many physical, chemical and biological processes taking place at
the interfaces. The study consequently is of great interest for many practical
purposes. We have analyzed the catalytic surface reaction over rough surfaces
generated by Random deposition and Random deposition with surface diffusion model.
The Multifractal scaling analysis has been used for the analysis of reaction
probability distribution (RPD) and RPD are transferred into a useful compact
form through the multifractal formalism namely through the t(q) and f(a) plots. We
have also analyzed catalytic surface reactions over fractal surface of
diffusion-limited aggregation and applied dynamic scaling theory to explore the
time-dependent effect involved in these reactions over fractal surface. Catalytic
surface reactions, by Langmuir-Hinshelwood mechanism, are also analyzed over
rough surfaces. The effect of surface roughness on coverage of the reacting
species and production rate is studied. The computer programs necessary for
these studies are developed in VISUAL FORTRAN.
4) Computational Chemistry
Hydrogen
bonding is a topic of considerable interest in physics, chemistry and biology.
The strong intermolecular interaction through hydrogen bonds in molecular
liquids results in a peculiar dynamical property. The structures of
hydrogen-bonded liquids are complicated due to molecular clusters and network
structures through hydrogen bonds. Hydrogen bonding has a considerable effect
on the microscopic as well as the macroscopic properties of fluid and plays a
fundamental role in the understanding and designing of process of biological
and environmental importance. Knowledge of the conformation and interactions of
amino acids in water is important for the ultimate understanding of protein
hydration and the role of water in biological systems. We have studied
hydrogen-bonding interactions in organic solvent-water and amino acids-water
complexes using ab initio and density functional theory (DFT) methods.
Further, the binding energies, dipole-dipole interaction are calculated using
the optimized geometries for these complexes. Effect of different basis sets is
also studied and the Basis set Superposition errors are calculated for these
complexes. We are also interested in Many body interaction and solvent effect
in biomolecules. We have used Gaussian 98 for these
studies.
I have many other research plans
and, of course, I am eager to pursue new directions and concepts, which can be
most profitable for today. I am always open for fruitful co-operation
with different research groups. If you are interested in my research expertise,
we can succeed together!
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