Where complex Physics meets simple Chemistry

Research

 

 

EXPERIMENTAL:

SERS and SERRS Spectroscopy

We are interested to explore the Raman and SERS spectra of organic molecules adsorbed on metal nano colloids and also on metallic nanoparticles organised in Langmuir –Blodgett Film. We are trying to explore the Electromagnetic mechanism of SERS from the theoretically simulated 3-Dimensional Finite Difference Time Domain (3D-FDTD) simulation studies. Attempts are being made to understand the Charge Transfer mechanism of SERS from ab initio and DFT calculations in conjunction with the experimental results. Recently we are interested in Fluorescence spectroscopic investigation of organic molecules adsorbed on isotropic and anisotropic gold and silver nanoclusters for advanced understanding of the SERS effect.

Scholars: Subhendu Chandra, Sannak Dutta Ray, Somsubhra Saha, Bipan Dutta

Associate: Dr. Ujjal kumar Sur, Dept. of Chemistry, Behala College.

Raman and temperature dependent FTIR spectroscopy

In the field of vibrational spectroscopy, we are performing rigorous normal coordinate analyses of organic molecules of biological and industrial significance to identify precisely the normal modes of vibrating molecules. We are also exploring the possible existences of various rotameric forms of some significant aliphatic organic molecules using the temperature dependent ( from cryo to high temperatures) FTIR and Raman spectroscopic techniques. The experimental results are complemented by high level ab initio / DFT molecular statics as well dynamics calculations. The solvent dependent changes in the vibrational signatures of organic molecules and preferential existence of the conformers are explained from the dipole-dipole solute-solvent interactions using ab initio Molecular Dynamics simulation studies. The 2- Dimensional correlation (2D-COS) spectroscopic techniques are utilized to explore the wavelength dependent Raman excitation profiles and to comprehend the presence of hidden species from the perturbation induced vibrational spectra of the molecules.

Scholar: Bipan Dutta

Photophysics & Photochemistry of organic molecules

We want to explore the ground state and excited state intra and/ or intermolecular proton transfer and charge transfer studies of some photo switchable organic molecules having donor and acceptor moieties from steady state and time-resolved spectroscopic technique. The various radiative and/ or non radiative ralaxation pathways of the molecule are explored from the excited state ROKS/ TDDFT ab initio molecular dynamics simulation studies. We are also interested to understand the conical intersection and avoided crossings between the ground and excited state non-adiabatic potential energy hypersurfaces leading to the breakdown of Born-Oppenheimer Approximations.

Scholar: Gopa Dutta (Pal)

Macromolecular interactions with metals/ nanoparticles at the air-water interface

Here we are interested to understand the protein / lipid / drug/ metal nanoparticles interactions in the presence and in the absence of water soluble vitamins at the air-water interface using Langmuir-Blodgett Technique. The effects of these interactions upon UV radiation are being explored. The experimental results are substantiated by molecular docking studies.

Associate: Debashis Ray

Metal-enhanced Fluorescence Spectroscopy (MEF)

We are exploring the Metal-Enhanced Fluorescence (MEF) of dye molecules adsorbed on gold nano rods (having various aspect ratios) organized in Langmuir Blodgett Films separated by fatty acid spacer layers of variable thicknesses. We are also trying to understand the physics behind MEF from the view point of coupling between surface Plasmon coupled emission (SPCE) and Localized Surface Plasmon resonance (SPR).

Scholars: Bipan Dutta

Associate: Dr. Rina De, Department of Physics, Raja Rammohan Ray Mahavidyalaya, Hooghly

THEORETICAL:

We want to understand the

i) Relaxation dynamics of photochromic molecules using abinio DFT and ROKS/ TD DFT excited state molecular dynamics calculations beyond Born Oppenheimer Approximation regime.

ii) Electric & Magnetic field distributions around plasmonic  nanoparticles using 3D-FDTD simulations

iii) Physics behind the origin of the conformational and rotational barrier of the molecules containing atmost two rotor groups on the basis of the unified approach to barrier energetics, natural bond orbital, nuclear virial, and relaxation analyses

Scholar: Bipan Dutta

Associate: Dr. Rina De, Dr Susmita Chakraborti