http://hdl.handle.net/2289/3429 2026-04-08T15:44:40Z 2026-04-08T15:44:40Z Sharma, Pranav http://hdl.handle.net/2289/8399 2025-05-22T10:45:01Z 2025-04-21T00:00:00Z

Title: How India rewrote the rules of space travel when it launched its first satellite Authors: Sharma, Pranav Description: Open Access

2025-04-21T00:00:00Z Raman, C.V. Krishnamurti, D. http://hdl.handle.net/2289/7151 2019-02-12T18:08:24Z 1952-12-01T00:00:00Z

Title: Iridescent Crystals Authors: Raman, C.V.; Krishnamurti, D. Description: Open Access

1952-12-01T00:00:00Z Viswanathan, K.S. http://hdl.handle.net/2289/7123 2019-01-23T15:08:55Z 1961-04-01T00:00:00Z

Title: The correlated Hartree-Fock equations and the generalised density matrices Authors: Viswanathan, K.S. Abstract: The paper deals with a study of correlation effects in many-electron systems. Coulomb correlation is introduced into the theory by multiplying the Slater determinant formed from the one-electron orbitals by a correlation factor which is a symmetric and increasing function of the inter-electronic distances. The integro-differential equations satisfied by the best one-electron orbitals have been been deduced for non-stationary systems. From the extended Hartree-Fock equations given by Löwdin, the integro-differential equations satisfied by the density matrices have been derived. An expression for the energy-matrix of the system which is helpful in deriving a correlated Thomas-Fermi charge distribution, has also been given. Description: Open Access

1961-04-01T00:00:00Z Viswanathan, K.S. http://hdl.handle.net/2289/7122 2019-01-23T15:08:42Z 1959-07-01T00:00:00Z

Title: The relativistic theory of chemical binding Authors: Viswanathan, K.S. Abstract: Starting from Breit’s relativistic equation for a system of two electrons, it is shown that for a hydrogen molecule (or for a system of two electrons moving in a field of cylindrical symmetry) the component of the total angular momentum (Jx) along the axis of the molecule (axis of symmetry) is a constant of motion. Thus every eigenstate of the system is simultaneously an eigenstate of Jx also, and a state of the system will specify, besides its energy, only the eigenvalue of the component of the angular momentum parallel to the axis of symmetry. The form of the four large components of the wave function relating to their dependence on the azimuthal co-ordinates has been given. The case of Russel-Saunders approximation has been considered in detail and the nature of the components of the wave function for the singlet and triplet states has been discussed. It is shown that the wave function for the ground state of the hydrogen molecule could be expressed as a sum of a set of symmetric functions of which the first term is the Heitler-London function, and that the wave function for a triplet state should be a superposition of anti-symmetric molecular orbitals. It is shown that relativistic theory brings about in a natural manner the facts relating to the ground state of the molecules C2 and O2. Finally, some remarks are made concerning the case of molecules for which the spinorbit and the spin-spin couplings are strong. Description: Open Access

1959-07-01T00:00:00Z