Fast-beam study of H2+ ions in an intense femtosecond laser field

A fast beam of H₂⁺ ions, produced from a low energy ion accelerator, has been used for the first time in intense laser field experiments. The technique has enabled neutral dissociation products to be analysed and detected for the first time in such studies. Energy spectra of neutral and ionized fragments, product yields as a function of focused laser intensity and angular distributions of neutral dissociation products have been measured. Significant differences are observed between the present results and those obtained from experiments involving neutral H₂ molecules. These differences are indicative of the precursor H₂ molecule playing an important and hitherto neglected formative role in the laser-induced fragmentation processes.