Abstract
Molecules exposed to few-cycle intense laser fields (> 1014 W/cm2) undergo a rapid bond breaking
process called Coulomb explosion. Since the momenta of the resultant fragment ions reflect the
geometrical structure of the target molecule, Coulomb explosion provides a direct access to the
instantaneous structure of molecules during chemical reaction. Combined with the pump-probe scheme
in ultrafast spectroscopy, Coulomb explosion imaging serves as a unique means to probe ultrafast
molecular reaction processes in real time. Here we review this novel approach in ultrafast spectroscopy,
with the applications to ultrafast isomerization of deuterated acetylene dication (C2D2
2+).
