ELECTRON-ENERGY-LOSS STUDY OF SUPEREXCITED HYDROGEN MOLECULES WITH THE COINCIDENCE DETECTION OF THE NEUTRAL DISSOCIATION

The electron energy-loss spectra of Hz have been measured in coinciden ce with the neutral dissociation leading to H(1s)+H(2p) near the first ionization potential at the electron impact energy of 150 eV and the scattering angles of 2 degrees and 10 degrees, and compared with ordin ary electron energy-loss spectra The two spectra, the coincident and t he ordinary ones, are similar to each other in shape below the energy level of H-2(+)(X(2) Sigma(g)(+), v(i) = 1), white they are different from each other above this energy level. Such a large change around v( i) = 1 is discussed in terms of the dynamics of superexcited hydrogen molecules, and the availability of this method for such studies is exa mined.