R K Singh
Articles written in Pramana – Journal of Physics
Volume 60 Issue 6 June 2003 pp 1203-1215
Relative cross sections, differential in energy and angle, for electrons ejected from CH4 and C3H8 molecules under 16.0 keV electron impact have been measured. Electrons were analyzed by a 45° parallel plate electrostatic analyzer at emission angles varying from 60° to 135° with energies from 50 eV to 1000 eV. The angular distributions of electrons exhibit structures which are found to arise from Coulomb and non-Coulomb interactions. Furthermore, the double differential cross sections of electrons ejected from C3H8 molecule are found to be higher in magnitude than those from CH4. This result supports the fact that the number of ejected electrons participating in collisions with C3H8 molecules is more than that in CH4. Also, the angular distributions of C-K-shell Auger electrons emitted from the target molecules have been studied and shown to be isotropic within the experimental uncertainty
Volume 63 Issue 2 August 2004 pp 233-237
The HgO-added YBa2Cu3O7−δ (YBCO) superconductor has been studied for its structural and superconducting properties. Polycrystalline YBCO samples were synthesized through solid-state reaction method by adding HgO in different concentrations without using oxygen annealing. All the samples showed a sharp superconducting transition temperature around 90 K. The X-ray diffraction patterns of all the samples revealed monophasic Y-123 nature. The structural studies were carried out by neutron scattering and Rietveld analysis. The neutron scattering revealed that Hg is not incorporated in the Y-123 system and has shown optimum oxygen concentration. The significant role played by the HgO is to provide oxygen ambient through its decomposition, thus changing the oxygen balance in favour of high Cu-valence state.
Volume 63 Issue 2 August 2004 pp 413-417
An extended three-body force shell model (ETSM) has been applied to investigate the static and dynamic properties of KCN
Volume 63 Issue 2 August 2004 pp 419-423
The motivation for the present work was gained from the recent publication on phonon dispersion curves (PDCs) of CsCN from the neutron scattering technique. We have applied the extended three-body force shell model (ETSM) by incorporating the effect of coupling between the translation modes and the orientation of cyanide molecules for the description of phonon dispersion curves of CsCN between the temperatures 195 and 295 K. Our results on PDCs in symmetric direction are in good agreement with the experimental data measured with inelastic neutron scattering technique.
Volume 71 Issue 1 July 2008 pp 181-186 Brief Reports
We have predicted the phase transition pressures and corresponding relative volume changes of EuO and EuS having NaCl-type structure under high pressure using three-body interaction potential (TBIP) approach. In addition, the conditions for relative stability in terms of modified Born criterion has been checked. Our calculated results of phase transitions, volume collapses and elastic behaviour of these compounds are found to be close to the experimental results. This shows that the inclusion of three-body interaction effects makes the present model suitable for high pressure studies.
Volume 94, 2020
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