Ultrafast hydrogen migration and induced fragmentation dynamics in propanol

Carbon backbones play an important role in ultrafast electronic relaxation processes following photoexcitation, particularly in the presence of another functional group such as -OH. We investigated the photoinduced single and double hydrogen migration, leading to formation of H$_{\mathrm{2}}$O$^{\mathrm{+}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$ respectively, through excitation by intense, ultrashort (\textasciitilde 10 fs), 800 nm laser pulses in two structural isomers of propanol. Our results show changes in the pathways of the time-resolved formation of H$_{\mathrm{2}}$O$^{\mathrm{+}}$ and H$_{\mathrm{3}}$O$^{\mathrm{+}}$, and the mediated bond dissociation observed at the dicationic states of the two propanol conformers. Using coincidence recoil ion momentum spectroscopy and state-of-the-art molecular dynamics simulations, we show the role of carbon chains in the time-resolved energy redistribution and relaxation mechanisms of photoexcited prototypical hydrocarbons.