Ultrafast isomerization in acetylene dication after carbon K-shell ionization

0487226 - FZÚ 2018 RIV GB eng J - Článek v odborném periodiku
Li, Z. - Inhester, L. - Liekhus-Schmaltz, C. - Curchod, B.F.E. - Snyder Jr., J.W. - Medvedev, Nikita - Cryan, J.P. - Osipov, T. - Pabst, S. - Vendrell, O. - Bucksbaum, P. - Martinez, T.J.
Ultrafast isomerization in acetylene dication after carbon K-shell ionization.
Nature Communications. Roč. 8, č. 1 (2017), s. 1-7, č. článku 453. E-ISSN 2041-1723
Grant CEP: GA MŠMT LG15013
Institucionální podpora: RVO:68378271
Klíčová slova: molecular-dynamics * conical intersection * electronic states * ab-initio * vinylidene
Obor OECD: Fluids and plasma physics (including surface physics)
Impakt faktor: 12.353, rok: 2017

Ultrafast proton migration and isomerization are key processes for acetylene and its ions. However, the mechanism for ultrafast isomerization of acetylene [HCCH]2+ to vinylidene [H2CC]2+ dication remains nebulous. Theoretical studies show a large potential barrier ( > 2 eV) for isomerization on low-lying dicationic states, implying picosecond or longer isomerization timescales. However, a recent experiment at a femtosecond X-ray free-electron laser suggests sub-100 fs isomerization. Here we address this contradiction with a complete theoretical study of the dynamics of acetylene dication produced by Auger decay after X-ray photoionization of the carbon atom K shell. We find no sub-100 fs isomerization, while reproducing the salient features of the time-resolved Coulomb imaging experiment. This work resolves the seeming contradiction between experiment and theory and also calls for careful interpretation of structural information from the widely applied Coulomb momentum imaging method.
Trvalý link: http://hdl.handle.net/11104/0281903