Slow neutrons have proved to be a very powerful probe for examining materials in general and hydrogenous materials in particular. In this article we review various neutron scattering techniques which have been utilised to investigate different aspects of a variety of hydrogenous materials. Translationally as well as orientationally disordered materials, ferroelectrics, superconductors, metal-hydrogen systems, polymers and biological molecules have been chosen as illustrative examples.

The present paper describes an algorithm which can generate, even on a small computer, arbitrarily long polymer chains, making sure that the configurations generated do not suffer from boundary effects. This has been achieved by employing the concept of a window, which is an analogue of virtual memory scheme. The algorithm has been tested for the case of dilute polymer solution.

The paper reviews the quasi-elastic neutron scattering activities at the Bhabha Atomic Research Centre and demonstrates how this technique gives information on rates and geometries of stochastic motions in liquids and solids.

Coherent inelastic neutron scattering measurements have been carried out on the high temperature superconductors Tl₂CaBa₂Cu₂O₈ (Tl-2122,T_c=107 K) and YBa₂Cu₃O₇ (Y-123,T_c=92 K), at the Dhruva reactor at Trombay. The density of phonon states in Tl-2122 is enhanced at 6–17 meV and reduced at 40–70meV compared to that in Y-123.

HighT_c phase (T_c ∼ 110 K) has been obtained in Bi-Sr-Ca-Cu-O system by partially substituting Bi by Pb. Magnetic hysteresis has been measured as a function of temperature. Critical current densities have been measured at 77 K both by transport and a.c. magnetization method in bulk samples for various concentrations of Pb. The results show that substitution of 15 at % Pb for Bi is most preferable for higher critical current density.