Single Crystal Phonon Scattering - Si in diamond structure

The differential cross section is given by $$ \begin{aligned} {\left(\frac{d^2\sigma}{d\Omega dE_f}\right)}_{\rm{coh}+1} = & \frac{k_f}{k_i} \frac{(2\pi)^3}{2v_0} \sum_s \sum_{\mathbf{\tau}} \frac{1}{E_s} \left| \sum_d \frac{\overline{b_d}}{\sqrt{M_d}} exp(-W_d) exp(i\mathbf(Q) . \mathbf{d}) \right|^2 \\ & \times (n_s + 1) \delta(\omega - \omega_s) \delta(\mathbf{Q}-\mathbf{q}-\mathbf{\tau}) \end{aligned} $$

Experimental data

Simple modeling

Phonon energies and polarizations were computed from VASP and phonopy.

Modeling convoluted with resolution function computed using MCViNE

This is similar to the previous result. The improvement was achieved by a convolution of the modeled intensity with a resolution function computed from a MCViNE simulation, in which a "$\delta$-function kernel" was used.

Full Monte Carlo ray-tracing simulation using MCViNE

This simulation includes two kernels: one for coherent single-phonon scattering, and one for multiphonon scattering in incoherent approximation.