Neutron scattering by liquid nitrogen and liquid oxygen

Measurements have been made of the neutron scattering structure factors of liquid nitrogen and liquid oxygen at 77 K and 84 K respectively in the Q-value range of 3 to 36 Å-1. ‘White’ incident thermal neutrons were produced in the wavelength range of 0·3 to 3·0 Å by a pulsed electron linac and detected in a total-scattering time-of-flight spectrometer. Qualitative agreement has been obtained between these present data and a simple molecular form factor in the Q-value range of 12–36 Å-1. Using reactor data [1], structure factors over a total Q-value range of 0·3 to 36 Å-1 were obtained. Fourier transforms of the structure factor curves yield pair distribution functions which show a distinct separation of the inter and intra-molecular distances in the liquid. A comparison is made with results for the solid phase.