To produce an odor sensation, a substance must be volatile and its molecules must come into contact with the olfactory end organ, which may require some measure of lipoid solubility. This much is generally agreed, but beyond this there has been no accepted theom of the triggering process by which the odorous molecule initiates a discharge of the olfactory nerve. In part, this ignorance has been due to the lack of any secure correlation between the odors of substances and the chemical constitution or reactivity of the odorous molecules, or their physical shapes or electrical properties. A correlation of odor with molecular vibrational modes would be consistent with most of the facts of olfactory chemistry, but this hypothesis has failed to win general acceptance up till now because, (1) there has been no direct evidence of a correlation between odor and vibrational frequency, and, (2) there has been no suggestion of a mechanism whereby a molecular vibration could trigger a nervous discharge. Some evidence bearing on both these objections has recently been brought forward which is of considerable interest in relation to the problem of insect attractancy and repellency (7, 8, 9, 10, 11).
Fano Resonance Resulting from a Tunable Interaction between Molecular Vibrational Modes and a Double Continuum of a Plasmonic Metamolecule
