Fragmentation of CD₄⁺ induced by intense ultrashort laser pulses*

The fragmentation of CD₄⁺ molecular ions is investigated by focusing intense ultrashort laser pulses‡ onto fast (keV) CD₄⁺ ion beam targets. A coincidence three-dimensional momentum imaging technique allows us to measure the laser induced charged and neutral fragments. One of our goals is to study the competition between different CD₄⁺ dissociation processes, specifically hydrogen elimination (CD₃⁺ + D), deprotonation (CD₃ + D⁺), and the hydrogen-molecule elimination (CD₂⁺ + D₂). In addition, we observe a very weak molecular hydrogen ion elimination (CD₄⁺ → CD₂ + D₂⁺). Curiously, some branching ratios show strong wavelength dependences. We will also discuss the kinetic energy release (KER) and angular distributions of these breakup processes, as well as other two- and three-body breakup channels following the ionization of CD₄⁺.



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