Wave-vector dependence in quasielastic neutron scattering

Article

Summary *

The wave-vector (k) dependence of the quasielastic (QE) intensity generated by neutrons scattered by particles moving under the action of one-dimensional potentials and weak stochastic forces is investigated in detail. It is shown that, in the low-k limit, the quasielastic intensity due to scatterers subject to symmetric potentials is proportional to k4, while asymmetric potentials will generally give rise to a k2 term. Formulas to evaluate the coefficient for an arbitrary term in a k expansion of the cross section are derived. It is also shown that the QE line consists of a superposition of Lorentzians generated by energy relaxation modes. A possible application to the soft-potential model of glasses is indicated. Information provided by the agent in SIGEVA