Kinetic Energy Distribution of H(2p) Atoms from Dissociative Excitation of H2.

The kinetic energy distribution of H(2p) atoms resulting from electron impact dissociation of H-2 has been measured for the first time with uv spectroscopy. A high resolution uv spectrometer was used for the measurement of the H Lyman-alpha emission line profiles at 20 and 100 eV electron impact energies. Analysis of the deconvolved 100 eV line profile reveals the existence of a narrow line peak and a broad pedestal base. Slow H(2p) atoms with peak energy near 80 meV produce the peak profile, which is nearly independent of impact energy. The wings of H Lyman-alpha arise from dissociative excitation of a series of doubly excited Q(1) and Q(2) states, which define the core orbitals. The fast atom energy distribution peaks at 4 eV.