Ion-ion coincidence imaging of dissociative ionization dynamics of formic acid in intense laser fields

We have studied the dissociative ionization dynamics of formic acid molecules with intense femtosecond laser pulses centered at 800 nm, employing the ion-ion coincidence imaging technique. Fragmentation reactions originating from both singly and doubly charged parent formic acid ions are observed. In this paper the kinetic energy distributions of several different ionic fragments will be presented. A clear difference in the kinetic energy distributions is observed between ionic fragments originating from the dissociation of the singly charged parent ion and those from the Coulomb explosion of the doubly charged parent ion. Channels exhibiting the emission of neutral hydrogen and channels exhibiting intra molecular hydrogen migration will also be discussed. We present a combined theoretical and experimental study to get to an understanding of the hydrogen migration mechanism at the molecular level.