An explicit electron-vibron model for olfactory inelastic electron transfer spectroscopy.

The vibrational theory of olfaction was posited to explain subtle effects in the sense of smell inexplicable by models in which molecular structure alone determines an odorant’s smell. Amazingly, behavioral and neurophysiological evidence suggests that humans and some insects can be trained to distinguish isotopologue molecules related by isotope substitution. How is it possible to smell a neutron? Inelastic electron transfer spectroscopy (IETS) is a proposed mechanism to explain such subtle olfactory effects: the vibrational spectrum of an appropriately-quantized odorant molecule may enhance a transfer rate in a discriminating electron transfer (ET) process. In contrast to existing models of olfactory IETS, the model presented here explicitly treats the dynamics of the dominant odorant vibrational mode. Power is dissipated directly from electron to environment and indirectly via damped odorant vibrations. The spectroscopic behavior in ET rate is unmasked if the direct-path dissipation is negligible. This may support olfactory isotopomer discrimination.