Abstract:
An improved nonlocal resonance model for the description of the nuclear dynamics of the H-2(-) collision complex is
developed. The model is based on the ab initio electron-H-2 scattering data of Berman et al at short internuclear
distances, the ab initio data of Senekowitsch et al for the bound (2)Sigma(u)(+) state of H-2(-) at intermediate
distances, and exhibits the correct polarization interaction at large internuclear distances. Cross sections for associative
detachment (AD) and dissociative attachment (DA) to rotationally and vibrationally excited molecules were calculated
for a wide range of energies and angular momenta with full inclusion of nonlocal effects. The calculated AD rate constant
at 300 K is 3.8 x 10(-9) cm(3) s(-1), which is significantly larger than the experimental value reported by Schmeltekopf
et al. A series of narrow low-energy orbiting resonances was found in the AD cross section. Our results compare well
with previous calculations of DA cross sections within the nonlocal resonance model. The DA cross section for
vibrationally and rotationally hot H-2 (T = 1400 K) has been calculated and compared with the experimental data of
Allan and Wong. It is demonstrated that the local-complex-potential approximation is an excellent approximation for the
associative detachment process, whereas it fails severely for the DA process in H-2.