Study of Unimolecular Reactions by Coulomb Explosion Imaging: The Nondecaying Vinylidene

Isomerization of a highly excited vibrational state of acetylene was studied using the Coulomb explosion imaging technique. A vinylidene isomer was prepared by electron photodetachment of the negative molecular ion and the corresponding distribution function of the nuclear configurations of the molecule was sampled after a time period of 3.5μs. The population of the vinylidene isomer was found to be significantly high ( ~50%), in contrast to the commonly accepted notion of vinylidene as a short-lived isomer.