R
Ranbir Singh
Researcher at Panjab University, Chandigarh
Publications - 12
Citations - 2981
Ranbir Singh is an academic researcher from Panjab University, Chandigarh. The author has contributed to research in topics: Excited state & Density functional theory. The author has an hindex of 8, co-authored 12 publications receiving 2975 citations.
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Developments in excited-state density functional theory
Ranbir Singh,B. M. Deb +1 more
TL;DR: In this paper, the authors discuss the reasons behind the apparent lack of success of density functional theory (DFT) with excited states of many-electron systems and describe various variational and non-variational approaches developed so far for dealing with this problem.
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A universal density criterion for correlating the radii and other properties of atoms and ions
TL;DR: In this paper, an improved Thomas-Fermi-Dirac (TFD) method was used to define a characteristic radius r D for a free atom or ion, where the electron density acquires the universal value of 0.008714.
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Density-functional calculations for doubly excited states of He, and
TL;DR: More than 200 low-lying and moderately high-lying doubly excited states of He-isoelectronic systems (Z = 2 - 5) have been studied in the nonrelativistic Hohenberg - Kohn - Sham density-functional framework by incorporating the nonvariational work-function exchange potential suggested by Harbola and Sahni and a simple parametrized local Wigner-type correlation functional as mentioned in this paper.
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Density functional calculation for doubly excited autoionizing states of helium atom
Ranbir Singh,B. M. Deb +1 more
TL;DR: Several doubly excited autoionizing states of He have been calculated within the density functional framework by employing the Harbola-Sahni exchange potential as mentioned in this paper, and correlation effects have been incorporated in the total effective potential through a Wigner-type correlation potential.