An exciplex mechanism for the quenching of singlet excited states of aliphatic ketones by carbon tetrachloride

Non-classical energy transfer from the excited singlet states of aliphatic ketones to carbon tetrachloride leads to sensitized decomposition products and fluorescence quenching. The correlation of the ionization potentials for a wide variety of such ketones with the corresponding quenching constants from fluorescence data has been rationalized by an exciplex mechanism. The correlation implies that charge transfer from the excited ketone to the carbon tetrachloride is a major contribution to the exciplex state for which two possible structures are tentatively proposed.