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Featured researches published by Rupam Sen.
Spectroscopy Letters | 2012
Rupam Sen; Ashim Kalyan; Raghunandan Das; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
ABSTRACT Using Hamiltonian based on Lie Algebraic method, the normal vibrational modes of Buckminsterfullerene were calculated. The model appeared to describe Carbon-Carbon stretching modes with lower number of algebraic parameters. The dynamical symmetry group of icosahedron molecule was taken into consideration to construct the model Hamiltonian in this framework. Casimir and Majorana invariant operators were also determined accordingly.
Fullerenes Nanotubes and Carbon Nanostructures | 2013
Rupam Sen; Ashim Kalyan; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
The vibrational energy levels of C20 isomers are calculated considering the local Hamiltonian of Morse potential using the U(2) Lie algebra. Here each bond of the molecule is replaced by a corresponding Lie algebra. Finally the local Hamiltonian is constructed considering the interacting Casimir and Majorana invariant operators. By constructing the Hamiltonian, we calculate the local mode vibrational energy levels of C20 isomers and thus compare the accuracy of algebraic model with PM3 model.
Fullerenes Nanotubes and Carbon Nanostructures | 2013
Rupam Sen; Ashim Kalyan; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
In this study, the Hamiltonian describing the stretching vibrational spectra of fullerenes C180 and C240 are calculated within the framework of the vibron model by using the dynamical U(2) Lie algebra. Here, every C-C bond of the molecule is replaced by a corresponding Lie algebra and finally the Hamiltonian is constructed considering the interacting Casimir and Majorana operators. The fundamental stretching vibrational energy levels of the carbon cluster C180 and C240 are then calculated using this Hamiltonian to fit the semi-empirical MNDO calculation.
Fullerenes Nanotubes and Carbon Nanostructures | 2013
Ashim Kalyan; Rupam Sen; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
Using the Lie algebraic method, the stretching fundamental IR active modes of vibrational energies of fullerenes C70 are calculated in the one-dimensional U(2) framework. By constructing the model Hamiltonian with the help of Casimir and Majorana invariant operators in this framework, we calculate the fundamental stretching IR active modes of vibration of fullerene C70 and compare the results with theoretical and experimental values to show the precision of algebraic model.
Fullerenes Nanotubes and Carbon Nanostructures | 2013
Rupam Sen; Ashim Kalyan; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
Molecular vibration spectra are of great significance in the study of molecular structures and characters. Here, an analytical method of Lie algebraic approach is imported into the domain of micro-scaled molecular spectra. The vibrational modes of fullerenes C50, C70 and C80 are calculated considering the C-C bond interactions. The algebraic Hamiltonian describing vibrational spectra of polyatomic molecules has been derived by using the dynamical U(2) Lie algebra. The calculations are performed within the framework of the vibron model with fewer numbers of algebraic parameters. The calculations show a reasonable agreement with previously published calculated and experimental results.
Polycyclic Aromatic Compounds | 2014
Surja Kumar Singha; Ashim Kalyan; Rupam Sen; Ramendu Bhattacharjee
The article is aimed at calculating the stretching vibrational spectra of fluorobenzene (C6H5F) using one-dimensional algebraic model. The Model Hamiltonian so constructed which seems to describe the C-C, C-F C-H, H-F stretching modes accurately using a relatively small set of well-defined parameters.
Fullerenes Nanotubes and Carbon Nanostructures | 2014
Rupam Sen; Ashim Kalyan; Nirmal Kumar Sarkar; Ramendu Bhattacharjee
Using Hamiltonian-based Lie Algebraic method, the stretching vibrational IR active modes of two stable isomers of fullerene C80 are calculated. The model appears to describe fundamental stretching modes with less number of algebraic parameters. In this study, the dynamical symmetry group of Cs symmetry is taken into consideration to construct the model Hamiltonian. Casimir and Majorana invariant operators are also determined accordingly. The calculated energies find an excellent exactitude with the simulated PM3 model.
Polycyclic Aromatic Compounds | 2016
Rupam Sen
This article investigates the stretching vibrational modes of carbon fullerenes (C24, C28, C32, and C50) by using one-dimensional U(2) algebra. Considering the molecular symmetry, the model Hamiltonian is constructed which is able to describe the fundamental “stretching modes” of the physical system with less number of algebraic parameters. The calculated energies find an excellent agreement with the theoretical data of harmonic force constant calculation.
Polycyclic Aromatic Compounds | 2014
Surja Kumar Singha; Ashim Kalyan; Rupam Sen; Ramendu Bhattacharjee
In this article, we calculate the different fundamental modes of benzene monomer and dimers using the algebraic method by considering the symmetry and Wilson numbering. The model Hamiltonian constructed describes the C‒C and C‒H stretching modes accurately with only four numbers of algebraic parameters. The present calculation not only predicts the different fundamental modes but also shows good agreement with the few observed DFT data.
Polycyclic Aromatic Compounds | 2014
Ratan Das; Rupam Sen; Ashim Kalyan; Raghunandan Das; Subha Gaurab Roy; Joydeep Choudhury; B. Indrajit Sharma; R. K. Thapa; Siddhartha Sankar Nath; Ramendu Bhattacharjee
In this article, using Lie algebraic technique and the expressions of the matrix elements of Majorana and Casimir operators, we obtain an effective Hamiltonian operator, which conveniently describes some stretching infra-red active mode of vibrations of monolayer graphene model of 30 atoms. The model finds the accuracy in results of density functional theory.