“…[15] The S 2 state is due to an n!3s Rydberg excitation and occurs around 6.2 eV, above which follows the three 3p states at around 6.9 eV. [16,17] The Rydberg states of the cycloketones have also been extensively investigated using absorption, [13,14,16,[18][19][20] resonance-enhanced multiphoton ionization (REMPI), [17,[21][22][23] electron ionization [4] as well as TR-MS. [24][25][26][27] The three cycloketones represent a set of molecules with an increasing number of internal degrees of freedom (27, 36, and 45) as well as different point-group symmetries (C s , C 2 , and C s for cyclobutanone, cyclopentanone and cyclohexanone, respectively) incorporating the same chromophore. Certain specific differences between the molecules are present which could influence the time-scale of excited-state dynamics.…”