Momentum-imaging investigations of the dissociation of D2+ and the isomerization of acetylene to vinylidene by intense short laser pulses

We present momentum images of the ionic products from the ionization of D-2 and C2H2 by short laser pulses. For D-2, we use a pump-probe approach to investigate the dependence of the enhanced ionization on the internuclear distance. Evidence for two ( not well separated) regions of enhancement is found near internuclear distances of 6 and 10 au. In the case of acetylene, we report clear evidence for the production of both acetylene and vinylidene dications with kinetic energy releases similar to those reported earlier by core electron removal. We also find very different angular distributions for the fragments in the two channels, consistent with a finite time for the isomerization.