fragmentation induced by intense ultrashort laser pulses*

The fragmentation of CD_n⁺ (n=2–3) in intense ultrashort laser pulses^‡ was investigated using an upgraded version of coincidence three-dimensional momentum imaging of fast (keV) molecular ion beams. One of the main goals of this study is to determine the relative importance of hydrogen elimination, CD_n⁺ → CD_n-1⁺ + D, versus deprotonation, CD_n⁺ → CD_n-1 + D⁺. Curiously, hydrogen elimination is also observed in the dissociation of the dication following ionization of CD₃⁺, namely CD₃²⁺ → CD₂²⁺ + D, though it is much smaller than the competing deprotonation process leading to CD₂⁺ + D⁺. Other two- and three-body breakup channels will be discussed also.

^‡780-nm, 25-fs, about 10¹⁵-W/cm² laser pulses at 10 kHz