Quantum vibration theory of smell gains credibility

How does our olfactory system interpret an odor molecule? Physicist Marshall Stoneham is trying to find out. His studies at University College London are putting Luca Turin’s controversial theory to the test. In Turin’s model, put forth in 1996, receptors are cued by the vibrational frequency of the odor molecule. This differs strongly from the leading theory, which supposes that the shape of the odor molecule allows it to fit like a key into the appropriate lock-like receptor. But while the shape theory is the one most accepted by scientists, it has not been proven. Shape still has a role in Turin’s model, however, being part of what determines the molecule’s overall vibrational frequency. Using quantum mechanics, says Turin’s model, an electron “tunnels” through the odor molecule, distorting its electrical field. Stoneham’s study supposed that an odor molecule sits between an electron donor and an electron receptor, while the electron “tunnels” its way to the receptor, thus activating it. The detailed structure of the receptors is unknown, but the calculations made by Stoneham and his colleagues came out favoring Turin’s mechanism. More about this can be found at Scientific American and Physorg.com.