Rabeet Singh

An accurate variational basis set for confined hydrogen atom

Deepak Singh, Rabeet Singh

Abstract We present a numerically stable, high-precision variational scheme for the confined hydrogen atom (CHA) enclosed within an impenetrable spherical cavity of radius R . To implement this scheme, we express the radial wavefunction in terms of a polynomial basis set of …

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Levy–Perdew–Sahni equation and its application to perform atomic calculations

Rabeet Singh, Ashish Kumar, Manoj K. Harbola

Levy-Perdew-Sahni (LPS) derived the connection between the asymptotic decay of density and the ionization potential of a many-electron system using the equation for the square root of density. For this, they employed an expression for the corresponding effective potential in terms of …

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A new variational wave-function ansatz for confined two-electron atomic systems

Rabeet Singh, Arup Banerjee

Abstract In this paper, we propose a simple variational ansatz, Ψ ( r 1 → , r 2 → ) = C sin ⁡ ( π r 1 r c ) r 1 sin ⁡ ( π r 2 r c ) …

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Modified Le Sech wavefunction for investigating confined two-electron atomic systems

Rabeet Singh, Arup Kumar Banerjee

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Corrigendum: Semianalytical wavefunctions and Kohn–Sham exchange–correlation potentials for two-electron atomic systems in two-dimensions (2020 J. Phys. B: At. Mol. Opt. Phys. 53 035001)

Rabeet Singh, Ashish Kumar, Manoj K. Harbola, Prasanjit Samal

Accurate effective potential for density amplitude and the corresponding Kohn–Sham exchange–correlation potential calculated from approximate wavefunctions

Ashish Kumar, Rabeet Singh, Manoj K. Harbola

Abstract Over the past few years it has been pointed out that direct inversion of accurate but approximate ground state densities leads to Kohn–Sham exchange–correlation (xc) potentials that can differ significantly from the exact xc potential of a given system. On the …

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Adiabatic connection in density functional theory in two-dimensions: A semi-analytic wavefunction based study for two-electron atomic systems

Rabeet Singh, Bikash Patra, Abhilash Patra, Manoj K. Harbola et autres

This work focuses on studying the adiabatic-connection in density functional theory in two dimensions. It employs a recently developed accurate form of wavefunction for two-electron systems. The explicit semianalytic form of the wavefunction makes it possible to calculate ground state wavefunctions, energies, …

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Semianalytical wavefunctions and Kohn–Sham exchange-correlation potentials for two-electron atomic systems in two-dimensions

Rabeet Singh, Ashish Kumar, Manoj K. Harbola, Prasanjit Samal

Abstract We propose accurate semianalytical wavefunctions for two-electron atomic systems in two-dimensions. These wavefunctions take into account the cusp conditions arising due to the Coulombic nature of external potential and electron–electron interaction, and the screening effects. The first wavefunction is motivated by …

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Universal nature of different methods of obtaining the exact Kohn–Sham exchange-correlation potential for a given density

Ashish Kumar, Rabeet Singh, Manoj K. Harbola

Abstract Finding the external potential or the Kohn–Sham (KS) potential for a given ground state density is a fundamental inverse problem in density functional theory. Furthermore, it is important in generating the exact exchange-correlation potential for a density which can then serve …

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A study of accurate exchange-correlation functionals through adiabatic connection

Manoj K. Harbola, Rabeet Singh

Universal nature of different methods of obtaining the exact Kohn-Sham exchange-correlation potential for a given density

Manoj K. Harbola, Ashish Kumar, Rabeet Singh

A study of accurate exchange-correlation functionals through adiabatic connection

Rabeet Singh, Manoj K. Harbola

A systematic way of improving exchange-correlation energy functionals of density functional theory has been to make them satisfy more and more exact relations. Starting from the initial generalized gradient approximation (GGA) functionals, this has culminated into the recently proposed SCAN (strongly constrained …

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