Formation of H 3O + by the soft X-ray ionization of ethanol clusters

Abstract

Time-of-flight mass spectra have been measured for inner-shell ionization of ethanol molecules, its clusters, and methanol clusters at the oxygen K-edge regions. Only in the case of the ethanol clusters, a fairly intense signal corresponding to H 3O + has been observed. The measurements for ethanol- d 1 (C 2H 5OD) suggest that at least one H atom in the H 3O + ion originates from the C 2H 5 group of neighbouring ethanol. It is proposed that in addition to the O–H⋯OH type hydrogen bonding in the ethanol clusters, the H in the C 2H 5 group and OH interact with each other.