Energy integrated neutron cross sections of an uniaxial unhindered quantum rotor XH₃

Abstract

The spin polarization of the ground state wave function of free uniaxial XH₃ rotors leads to a strong, angle dependent background in the energy integrated neutron scattering even at moderately low temperatures: the large incoherent cross section of individual protons becomes coherent. In the static approximation the powder average of this modulated background is given by a spherical Bessel function j ₀(QR) with R the proton-proton distance.