State-to-field vibrational energy transfer from optically pumped vibrational levels in S-1 pDFB by single collisions with Ar at 300 K has been characterized for 18 initial levels whose energies range from 0 to about 2500 cm(-1) where the density of levels is about 200 per cm(-1). The rate constants vary according to the zero order identity of the initially pumped level, even for the highest levels that are of extensively mixed vibrational character. In the midst of these variations, the constants gradually increase as higher energy levels are pumped, but the energy regime where the rate constants level off has apparently not yet been reached. The largest rate constants are about 60% of the Lennard-Jones value. Transfers involving single quantum changes in the lowest frequency mode, nu(30)’ = 120 cm(-1), are the dominant single channels for all levels. These channels result in elevated rate constants for initial levels that contain quanta of nu(30)’. If the state-to-state nu(30)’ contributions are subtracted from the state-to-field rate constants, the entire set of rate constants has close similarity to that for benzene + CO over the same S-1 energy range. Attempts to model the state-to-field rate constants using propensity rules that describe well many S-1 pDFB state-to-state transfers are only partially successful. The modeling shows, however, that increase of state-to-field rate constants at higher energies is primarily a consequence of increasing numbers of state-to-state channels that involve larger vibrational quantum number changes (Delta upsilon greater than or equal to 3).