Substituent Effects on The Mechanisms and Dynamics of H<m:msubsup> 3 + Formation from Organic Molecules In Strong Fields

Recent studies from our groups combining femtosecond time-resolved dynamics, photoion-photoion coincidence measurements, and theory have provided evidence for the existence of two reaction pathways for the formation of H₃⁺ from methanol under strong-field ionization. Both reaction pathways are initiated by the ultrafast double ionization of the parent molecule and proceed through prompt formation of a roaming neutral H₂ molecule. The roaming H₂ fragment abstracts a third proton from the methyl carbon or from the hydroxyl oxygen leading to the formation of H₃⁺. We have extended the study to a series of alcohols presenting an increased number of hydrogen atoms and thus H₃⁺ f>ormation pathways: methanol (CH₃OH), ethanol (CH₃CH₂OH), 1-propanol (CH₃CH₂CH₂OH), 2-propanol(CH₃CH(OH)CH₃), and tert-butanol ((CH₃)₃ COH). Similarly, we have studied the substitution of oxygen with sulfur, comparing ethanol and ethanethiol. We will discuss the new pathways found and their relative yields.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Atomic, Molecular and Optical Sciences Program under Award Number SISGR (DE-SC0002325).