Determination of internal energy distribution inNa2+produced by associative-ionization collisions in crossed beams

We report the analysis of vibrational and rotational energy of ${\mathrm{Na}}_2$ ${\mathrm{}}^{+}$ ions produced by associative ionization (AI) in two processes: Na(3p)+Na(3p)→${\mathrm{Na}}_2$ ${\mathrm{}}^{+}$+e and Na(3s)+Na(6p)→${\mathrm{Na}}_2$ ${\mathrm{}}^{+}$+e. The nascent distributions are measured using photofragment translational spectroscopy. The results show that AI produces vibrationally excited ${\mathrm{Na}}_2$ ${\mathrm{}}^{+}$ with a distribution increasing approximately linearly with vibrational level. Rotational distributions indicate a short-range opacity function for AI with a maximum impact parameter of about 2 Å in both processes listed above.