The dependence on initial configuration of strong field-driven isomerization of neutral and ionic C$_2$H$_2$ targets
POSTER
Abstract
As a test bed for hydrogen migration, the conversion between the C$_2$H$_2$ molecule's acetylene (HCCH) and vinylidene (H$_2$CC) isomers has been a subject of great interest. We further explore isomerization of this system, examining the ultrafast laser-induced dynamics of C$_2$H$_2^q$ ion beam targets. These ion beams are generated with various initial configurations, including HCCH, H$_2$CC, and \emph{cis}/\emph{trans}. We show that the branching ratio between acetylene-like (CH$^{q_1}$ + CH$^{q_2}$) and vinylidene-like (C$^{q_1}$ + CH$_2^{q_2}$) fragmentation$^{\dag}$, measured using a coincidence 3D momentum imaging technique, exhibits a strong dependence on the target's initial configuration. Specifically, while an HCCH target, such as a C$_2$H$_2^+$ beam produced from C$_2$H$_2$, undergoes acetylene-like and vinylidene-like breakup at comparable levels, for H$_2$CC targets, there is a distinct preference for the latter. For example, acetylene breakup is negligible for C$_2$H$_2^-$. \\ \\ $^{\dag}$Includes CH + CH and C + CH$_2$
*Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U. S. Department of Energy under award \#DE-FG02-86ER13491. EW was also supported by National Science Foundation grant PHY-1723002.