Studies of low-lying triplet states in 1,3-C4F6, c-C4F6 and 2-C4F6 by electron energy-loss spectroscopy and ab initio calculations

Abstract This Letter reports on the first measurements of the lowest lying triplet states as studied by electron energy loss spectroscopy for C 4 F 6 isomers, hexafluoro-1,3-butadiene (1,3-C 4 F 6 ), hexafluorocyclobutene (c-C 4 F 6 ) and hexafluoro-2-butyne (2-C 4 F 6 ). This study has been performed at an incident electron energy of 30 eV, 30°, whilst sweeping the energy loss over the range 2.0–15.0 eV. The electronic state spectroscopy has been investigated and the assignments supported by multi-reference quantum chemical calculations. The transition to the steepest electronic excited potential energy curve, is suggested to be dominant for 2-C 4 F 6 , due to the large broadening in its energy profile.