Cover ; Introduction to the Theory of Thermal Neutron Scattering ; Title ; Copyright ; CONTENTS ; PREFACE ; 1 Introduction ; 1.1 Basic properties of the neutron ; 1.2 Numerical values for velocity, energy, wavelength ; 1.3 Definitions of scattering cross-sections.

1.4 Scattering of neutrons by a single fixed nucleus 2 Nuclear scattering
basic theory ; 2.1 Introduction ; 2.2 Fermi's golden rule ; 2.3 Expression for d2v/d] dE' ; Fourier transform of the potential function ; Fermi pseudopotential ; Integral representation of the d-function for energy.

Sum over n, average over n 2.4 Coherent and incoherent scattering ; 3 Nuclear scattering by crystals ; 3.1 Introduction ; 3.2 Normal modes ; 3.3 Probability function for a harmonic oscillator ; 3.4 Development of (exp U exp V) ; 3.5 Phonon expansion ; 3.6 Coherent elastic scattering ; Bragg's law.

Debye-Waller factor Non-Bravais crystals ; Methods of measuring Bragg scattering ; 3.7 Coherent one-phonon scattering ; Cross
sections ; Measurement of phonon dispersion relations ; Polarisation vectors ; Anharmonic forces ; 3.8 Coherent multiphonon scattering.

3.9 Incoherent scattering 3.10 Multiphonon cross-sections
approximation methods ; Incoherent approximation ; Mass expansion ; Examples ; 4 Correlation functions in nuclear scattering ; 4.1 Definitions of I(k, t), G(r, t), and S(k, }) ; 4.2 Expressions for G(r, t) and Gs(r, t).