Jyoti Sood

Anisotropic diffusion of a fluid confined to different geometries at the nanoscale

Self-diffusion coefficients of a fluid confined to slab and cylindrical geometries at the nanoscale with varying widths have been studied by considering different density profiles. The average second frequency sum rule of a velocity autocorrelation function in a direction parallel and perpendicular to the wall has been evaluated. It is found that confinement to the nano length scale results in anisotropic diffusion and the diffusion coefficient is directly dependent on the width of the channel and the density profile.

Density fluctuation spectra in Ar36 fluid having number density 21, 5 and 2 nm-3

Abstract Making use of the recently proposed modified microscopic theory by the authors, it has been possible to explain quantitatively the observed dynamics of a Van der Waals fluid, Ar36 when the number density of Ar atoms varies from 2, 5 to 21 particles/nm3 in the momentum transfer region extending to almost two orders of magnitude in the wave vector from the Rayleigh regime.

Collective Dynamics of Liquid Potassium Near Melting Point

The dynamical structure factor, S(q,ω) of liquid potassium has been evaluated for different values of wave vector, near its melting point using Mori’s memory function formalism. The results obtained using single relaxation time model have been found to be in good agreement with recent inelastic X‐ray scattering experiments.

Thermal Neutron Scattering and Transport in Methane at 20K

Abstract A thermal neutron scattering kernel in methane has been suggested which takes into account the contributions from both phonon and libron exchange processes. The observed total neutron scattering cross-section can be explained at 20 K, when as many as fourteen libron exchange processes are considered in the thermal neutron scattering kernel along with phonon exchange processes upto two quanta. Using the suggested scattering kernel, thermal neutron transport under different conditions like time dependent, space dependent and steady state neutron spectra have been studied at 20 K. The results of these studies are quite different from other hydrogenous moderatorslike ice, etc. The production of intense beams of cold neutrons at 20 K and below indicate that normal methane is a better moderator for finite sizes of the assembly while heavy methane is a better source of cold neutrons for infinite sizes of the assembly as compared to other hydrogenous moderators.