Photodissociation kinetics of the isobutanal radical cation: a combined experimental and theoretical study

The competitive photodissociation kinetics of the isobutanal radical cation ((CH3)(2)CHCHO+center dot, 1) were investigated using experimental and theoretical methods. The photodissociation was followed by the 2 + 1 REMPI process in the gas phase. The reaction pathways for the main product ions with m/z 43 and 29 were determined by calculating the potential energy surface of the dissociation with the G4 method. Through a kinetic analysis using RRKM calculations, we proposed that the main photodissociation pathways were 1 -> (CH3)(2)CH+ + CHO center dot, 1 -> (CH3)(2)CH+ + H-center dot + CO, and 1 -> CH3CH2COCH3+center dot -> CH3CH2+ + CH3 center dot + CO.