Photoionization and dissociation study of 2-methyl-2-propen-1-ol: Experimental and theoretical insights

The photoionization and dissociation of 2-methyl-2-propen-1-ol (MPO) have been investigated by using molecular beam experimental apparatus with tunable vacuum ultraviolet synchrotron radiation in the photon energy region of 8.0–15.5 eV. The photoionization efficiency (PIE) curves for molecule ion and fragment ions: C 4 H 8 O + , C 4 H 7 O + , C 3 H 5 O + , C 4 H 7 + , C 4 H 6 + , C 4 H 5 + , C 2 H 4 O + , C 2 H 3 O + , C 3 H 6 + , C 3 H 5 + , C 3 H 3 + , CH 3 O + , CHO + have been measured, and the ionization energy (IE) and the appearance energies (AEs) of the fragment ions have been obtained. The stable species and the first order saddle points have been calculated on the CCSD(T)/cc-pvTZ//B3LYP/6-31+G(d,p) level. With com-bination of theoretical and experimental results, the dissociative photoionization pathways of 2-methyl-2-propen-1-ol are proposed. Hydrogen migrations within the molecule are the dominant processes in most of the fragmentation pathways of MPO.