| Abstract: | The π*←n excited state kinetics of hexafluoroacetone are reinvestigated in the presence of a vibrational relaxer and sufficient triplet state quencher so that only the reactions of the electronically excited upper singlet state are examined. From a Stern–Volmer type analysis it is concluded that vibrational relaxation of the initially formed vibrationally and electronically excited upper singlet state is via a multistage collisional mechanism. An activation energy of about 6 kcal/mole is reported for the unimolecular decomposition of the upper singlet state. |
