  Combining the augmented space representation for phonons with a generalized
version of Yonezawa-Matsubara diagrammatic technique, we have set up a
formalism to seperate the coherent and incoherent part of the total intensity
of thermal neutron scattering from disordered alloys. This is done exacly
without taking any recourse to mean-field like approximation (as done
previously). The formalism includes disorder in masses, force constants and
scattering lengths. Implementation of the formalism to realistic situations is
performed by an augmented space Block recursion which calculates entire Green
matrix and self energy matrix which in turn is needed to evaluate the coherent
and incoherent intensities. we apply the formalism to NiPd and NiPt alloys.
Numerical results on coherent and incoherent scattering cross sections are
presented along the highest symmetry directions. Finally the incoherent
intensities are compared with the CPA and also with experiments.
