The DEGAS 2 Monte Carlo neutral transport code and its multispecies, Collisional-Radiative, Atomic and Molecular Data code (CRAMD) have been developed for the purpose of simulating highly radiative divertors with temperatures eV and electron densities m-3. The coupled codes are used to calculate the spatial variation of the Balmer- emission in a fixed background plasma obtained from a detached discharge in the Alcator C-Mod device. Vibrationally excited hydrogen molecules lead to recombination channels which are predicted by CRAMD to be significant at lower densities and higher temperatures than the familiar three-body processes. The relative importance of the two processes in the detached C-Mod divertor is evaluated. Ion-neutral elastic scattering is also examined.