  The non-equilibrium Green's function (NEGF) method with B\"uttiker probe
scattering self-energies is assessed by comparing its predictions for the
thermal boundary resistance with molecular dynamics (MD) simulations. For
simplicity, the interface of Si/heavy-Si is considered, where heavy-Si differs
from Si only in the mass value. With B\"uttiker probe scattering parameters
tuned against MD in homogeneous Si, the NEGF-predicted thermal boundary
resistance quantitatively agrees with MD for wide mass ratios. Artificial
resistances that the unaltered Landauer approach yield at virtual interfaces in
homogeneous systems are absent in the present NEGF approach. Spectral
information result from NEGF in its natural representation without further
transformations. The spectral results show that the scattering between
different phonon modes plays a crucial role in thermal transport across
interfaces. B\"uttiker probes provide an efficient and reliable way to include
anharmonicity in phonon related NEGF. NEGF including the B\"uttiker probes can
reliably predict phonon transport across interfaces and at finite temperatures.
