First experimental observation on different ionic states of the tert-butoxy [(CH3)3CO*] radical

A continuous tert-butoxy (CH3)+CO* radical beam is produced in situ by respective pyrolysis of both (CH3)3CONO at 115(+/-0.5) degrees C and (CH3)3COOC(CH3)3 at 87(+/- 0.5) degrees C. By combining the HeI photoelectron (PE) spectrum with the improved density function theory (DFT) calculations, we have concluded that the (CH3)3CO* radical has C3V symmetry and X2E ground state. The study does not only provide the ionization energies of different ionic states of the (CH3)3CO* radical for the first time, but also the first example in which there have been similar vibrational structures in different ionic states caused by removal of the electron on an orbital. It is also pointed out that (CH3)3CONO is a good source for obtaining the (CH3)3CO* radical beam, and that NO is a stable regent for the active radical. The results will promote the studies in electron spin resonance (ESR) research on the mechanisms of both the initiation of the formation of a new radical and the radical-chain polymerization in which the (CH3)3CO* radical participates.