Two-Body Dissociation of Formic Acid Following Double Ionization by Ultrafast Laser Pulses*

While formic acid (HCOOH) is a relatively small, planar polyatomic molecule, it contains three atomic species. Formic acid displays complicated dynamics following strong-field ionization, including hydrogen migration and bond rearrangement channels.  Deuterium tagging combined with coincidence momentum imaging measurements of all fragment ions allows for the exploration of the two-body dissociation channels resulting from double ionization.  The branching ratios, kinetic energy release, and angular distributions for two-body double ionization channels obtained with 25-fs laser pulses centered at 780 nm and a peak intensity of 2×10¹⁵ W/cm² are presented.  The role of the hydroxyl and the carbonyl hydrogen atoms is explored.