Molecular enhancement of Balmer emissions following foil-induced dissociation of fast H2+ and H3+ ions

Relative emission yields of Balmer lines as functions of the dwell time (t/sub D/ = 0.97--54.1 fs) in thin carbon foils (2--68 μg/cm2) have been measured with (0.2--0.8)-MeV/amu H+, H2+, and H3+ incident on thin carbon foils. Large molecular effects for emission yields of Balmer lines have been observed for H2+ and H3+, where the molecular effect for H3+ is larger than that for H2+. The molecular effects for H2+ and H3+ depend on the principal quantum number (n = 3--6), but this n dependence disappears at the largest t/sub D/ ( = 54.1 fs). The molecular effects rapidly decrease with increasing t/sub D/ in the small-t/sub D/ (< or approx. =2 fs) region and more slowly decrease in the large-t/sub D/ (> or approx. =2 fs) region. The magnitudes of the molecular effects at the largest t/sub D/ ( = 54.1 fs) are in good agreement with those by Andresen et al. [Phys. Scr. 19, 335 (1979)]. Relative populations of n-state hydrogens in the large-t/sub D/ (> or approx. =2 fs) region have been derived from the relative yields of Balmer lines as functions of n and t/sub D/. The molecular enhancement for relative populations of n-state hydrogens for H2+ depends on n and t/sub D/, and decreases with increasing t/sub D/ and increases with increasing n