S N Datta
Articles written in Pramana – Journal of Physics
Volume 28 Issue 6 June 1987 pp 633-639 Particle Physics
Relativistic extension of the Hohenberg-Kohn theorem
Using the configuration-space Hamiltonian
Volume 28 Issue 6 June 1987 pp 653-660 Molecular Physics
Quenching of excitations in an impure molecular crystal
The rate of quenching of excitons in a one-dimensional molecular crystal by an impurity is quantum-mechanically calculated.
Volume 30 Issue 5 May 1988 pp 387-405 Molecular Physics
The minimax technique in relativistic Hartree-Fock calculations
Using the set of trial spinors$$\left\{ {N_i \left( {_{\hat \Omega _i u_i }^{u_i } } \right), i = 1, \ldots , N} \right\}$$ and the Dirac-Coulomb Hamiltonian (
Volume 31 Issue 1 July 1988 pp 1- Erratum
The minimax technique in relativistic Hartree-Fock calculations
Volume 38 Issue 1 January 1992 pp 51-75
Bound state solutions of the two-electron Dirac-Coulomb equation
We present a variational method for solving the two-electron Dirac-Coulomb equation. When the expectation value of the Dirac-Coulomb Hamiltonian is made stationary for all possible variations of the different components of a well-behaved trial function one obtains solutions representative of the physical bound state wave functions. The ground state wave function is derived from the application of a minimax principle. Since the trial function remains well-behaved, the method remains safe from the twin demons of variational collapse and continuum dissolution.
The ground state wave function thus derived can be interpreted as a linear combination of different configurations. In particular, the admixing of intermediate states having one (two) electron(s) deexcited to a negative-energy orbital (orbitals) contributes a second-order level shift
If one extends the relativistic configuration interaction (RCI) treatment by additionally including negative-energy and mixed-energy
Volume 38 Issue 5 May 1992 pp 521-530 Research Articles
Examples of the minimax technique in relativistic atomic one-electron calculations
Several examples of the application of the minimax technique to relativistic calculations on one-electron atoms are given here. Normalizable eigenfunctions corresponding to the ground states of one-electron atoms with various angular momenta are derived analytically.
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