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Tapan K. Mukherjee

Bio: Tapan K. Mukherjee is an academic researcher from Narula Institute of Technology. The author has contributed to research in topics: Excited state & Plasma. The author has an hindex of 14, co-authored 60 publications receiving 654 citations. Previous affiliations of Tapan K. Mukherjee include Kandi Raj College & Indian Association for the Cultivation of Science.


Papers
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Journal ArticleDOI
TL;DR: In this article, an accurate variational calculation has been performed for the groundstate energy values of confined two-electron isoelectronic series from He to Ar16+, the confinement is obtained by embedding the ion in an overall charge neutral environment like that of a plasma.
Abstract: An accurate variational calculation has been performed for the ground-state-energy values of confined two-electron isoelectronic series from He to Ar16+. The confinement is obtained by embedding the ion in an overall charge neutral environment like that of a plasma. The confinement potential is chosen as that of a screened Coulomb potential between charges, obtained from a Debye model. The wave function is expanded in terms of product basis sets involving interparticle coordinates. The energy levels are found to be less bound with an increase of the screening parameter and ultimately become unstable. One- and two-particle moments have been calculated for the first time under such screening. The study is expected to throw new light on the behavior of the energy levels of foreign atoms embedded in an overall neutral environment which can be treated like a plasma.

63 citations

Journal ArticleDOI
TL;DR: In this article, the effect of environment like that of a plasma on the ground state energy of positronium plus ion (Ps − ) has been estimated variationally using multi-term correlated basis sets.

43 citations

Journal ArticleDOI
TL;DR: In this paper, an approach to resolve the long-drawn problem of numerical instability for evaluating two-electron integrals with an extended basis inside a finite domain is presented, and the present values of electron densities corresponding to the disappearance of different spectral lines obtained within the framework of an ion-sphere potential show excellent agreement with Orion laser experiments in Al plasma and with recent theories.
Abstract: In this work, the controversy between the interpretations of recent measurements on dense aluminum plasma created with the Linac coherent light source (LCLS) x-ray free electron laser (FEL) and the Orion laser has been addressed. In both kinds of experiments, heliumlike and hydrogenlike spectral lines are used for plasma diagnostics. However, there exist no precise theoretical calculations for He-like ions within a dense plasma environment. The strong need for an accurate theoretical estimate for spectral properties of He-like ions in a strongly coupled plasma environment leads us to perform ab initio calculations in the framework of the Rayleigh-Ritz variation principle in Hylleraas coordinates where an ion-sphere potential is used. An approach to resolve the long-drawn problem of numerical instability for evaluating two-electron integrals with an extended basis inside a finite domain is presented here. The present values of electron densities corresponding to the disappearance of different spectral lines obtained within the framework of an ion-sphere potential show excellent agreement with Orion laser experiments in Al plasma and with recent theories. Moreover, this method is extended to predict the critical plasma densities at which the spectral lines of H-like and He-like carbon and argon ions disappear. Incidental degeneracy and level-crossing phenomenamore » are being reported for two-electron ions embedded in strongly coupled plasma. Thermodynamic pressure experienced by the ions in their respective ground states inside the ion spheres is also reported.« less

42 citations

Journal ArticleDOI
TL;DR: In this paper, the energy eigenvalues of two p electrons of Be 2 + ion and D o 1, 3 states due to 2 pnd configuration of Li + and Be 2+ ion in the Debye plasma environment are reported for the first time.
Abstract: Extensive non-relativistic variational calculations for estimating the energy values of 2 pnd ( D o 1 , 3 ) states [ n = 3 – 6 ] of two electron atoms (He, Li + , Be 2 + ) and 2 pnp ( P e 1 ) [ n = 3 – 8 ] and 2 pnp ( P e 3 ) states [ n = 2 – 7 ] of Be 2 + under weakly coupled plasma screening have been performed using explicitly correlated Hylleraas type basis. The modified energy eigenvalues of P e 1 , 3 states arising from two p electrons of Be 2 + ion and D o 1 , 3 states due to 2 pnd configuration of Li + and Be 2 + ion in the Debye plasma environment are being reported for the first time. The effect of plasma has been incorporated through the Debye screening model. The system tends towards gradual instability and the number of bound states reduces with increasing plasma coupling strength. The wavelengths for 2 pn ′ p ( P e 1 ) [ n ′ = 3 – 8 ] → 2 pnd ( D o 1 ) [ n = 3 – 6 ] and 2 pn ′ p ( P e 3 ) [ n ′ = 2 – 8 ] → 2 pnd ( D o 3 ) [ n = 3 – 6 ] transitions in plasma embedded two electron atoms have also been reported.

39 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of spherical confinement on the ground state of helium-like ions (Z = 1−5) and the first four (1Se) excited states for Z = 2−5 have been analyzed in detail by using correlated Hylleraas basis sets within the variational framework.
Abstract: The effect of spherical confinement on the ground state of helium-like ions (Z = 1–5) and the first four (1Se) excited states for Z = 2–5 have been analyzed in detail by using correlated Hylleraas basis sets within the variational framework. The correlated wave functions used here are consistent with the finite boundary conditions due to spherical confinement. The present energy values and the thermodynamic pressure generated for the confined ions as well as the critical values of the confining radii close to the fragmentation limit can be set as a benchmark for future references.

38 citations


Cited by
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Journal ArticleDOI
TL;DR: Phenomenological approaches on the basis of simple model potentials for the description of various situations where the atom is spacially confined, such as as atoms inside a C60-like environment or in impenetrable cavities of small radii are reviewed along with the trends in modifications in structure and photoionization of such confined atoms as mentioned in this paper.

202 citations

Journal Article
TL;DR: Evidence is found for two universally connected Efimov trimers and their associated four-body bound states near a lithium resonance that can be directly related to different few-body processes.
Abstract: Under certain circumstances, three or more interacting particles may form bound states. Although the general few-body problem is not analytically solvable, the so-called Efimov trimers appear for a system of three particles with resonant two-body interactions. The binding energies of these trimers are predicted to be universally connected to each other, independent of the microscopic details of the interaction. By exploiting a Feshbach resonance to widely tune the interactions between trapped ultracold lithium atoms, we find evidence for two universally connected Efimov trimers and their associated four-body bound states. A total of 11 precisely determined three- and four-body features are found in the inelastic-loss spectrum. Their relative locations on either side of the resonance agree well with universal theory, whereas a systematic deviation from universality is found when comparing features across the resonance.

177 citations

Journal ArticleDOI
TL;DR: The Ratip program has been developed as a scalar Fortran 90/95 code and provides a simple make feature which help port the code to different platforms and architectures and makes available a major part of the code for public use.

163 citations

Book ChapterDOI
TL;DR: In this article, the effect of spatial and other external confinements on the ground and excited state energy levels of many electron atoms, ions and exotic systems is discussed, and the spectral line shifts under strongly coupled plasma have been compared with data available from laser plasma experiments.
Abstract: The effect of spatial and other external confinements on the ground and excited state energy levels of many electron atoms, ions and exotic systems is discussed. Special emphasis is given to analyzing and estimating the changes in the spectral properties of plasma embedded systems in which, apart from changes in the free particle potential due to atom plasma interaction, spatial confinement enters through the introduction of boundary conditions. Effects of weak as well as strong plasma on the dipole polarizabilities, ionization potentials, singly and doubly excited state energy levels, oscillator strengths and transition probabilities have been discussed using simple plasma models but adopting rigorous quantum chemical methods. The spectral line shifts under strongly coupled plasma have been compared with data available from laser plasma experiments. Specific attention has been given to extremely accurate estimates of the energies of different three-body systems under plasma environments. The importance of the use of finite boundary conditions originating from spatial confinement of the plasma has been demonstrated and the effect of electron correlation in estimating various confined atomic properties is shown. Attempt has been made to interpret the changes in the spectral properties of atoms trapped in cavities inside liquid helium environments, by comparing the results estimated on the basis of current quantum chemical methodologies with the data available from laser induced fluorescence experiments.

120 citations

Journal ArticleDOI
TL;DR: In this paper, the 2s 21 s e ionization resonance state of the hydrogen negative ion embedded in Debye plasmas is determined by calculating the density of resonance states using the stabilization method.
Abstract: The 2s 21 S e autoionization resonance state of the hydrogen negative ion embedded in Debye plasmas is determined by calculating the density of resonance states using the stabilization method. The electron affinity of the hydrogen atom is also estimated for various Debye lengths.A screened Coulomb potential obtained from the Debye model is used to represent the interaction between the charged particles. A correlated wave function consisting of a generalized exponential expansion has been used to represent the correlation effect between the three charged particles. The screening effect is taken care of forallpairsofthechargedparticles.Thecalculatedresonanceenergiesandwidths for various Debye parameters ranging from infinity to a small value along with the electron affinity are reported.

84 citations