Evaluation of the neutron scattering cross-section for light water by molecular dynamics

The neutron scattering cross-section for light water is evaluated by means of molecular dynamics (MD) simulation for incident neutron energies from 1μeV to 10 eV at six temperatures between 293.6 and 800 K. In the evaluation, the velocity autocorrelation functions for hydrogen and oxygen are calculated from trajectory data and used for the reconstruction of the double differential scattering cross-section. Typical results on differential and total cross-sections are presented together with experimental data. As compared with ENDF/B-VII, better agreement with experiments is found on the total cross-section below several meV. Hence, the present MD-based approach can serve for the new method of generating the thermal neutron scattering cross-section library for light water.