Soft x-ray ionization and fragmentation of n- and iso-propanol

Threshold electron and total ion yield spectra are presented for the near C and O 1s edge photoexcitation of n- and iso-propanol. To our knowledge these are the first such data for iso-propanol, and represent the first direct measurement of the core ionization energies of these molecules by threshold photoelectron spectroscopy. In particular, the C 1s energies for n-propanol are found to be lower (by about 0.5 eV) than determined indirectly in a previous study. Application of multiple coincidence techniques has enabled determination of the branching ratios of the dissociative multiple ionization channels uniquely associated with each core edge in both molecules. These show evidence for a greater degree of energy localization in n-propanol than in iso-propanol, and for the existence of long-lived excited states, allowing intramolecular energy transfer to occur.