부산대학교 도서관

The excitation spectrum for producing Lyman-..cap alpha.. fluorescence by photodissociating H/sub 2/ has been obtained with 0.12 A bandwidth in the dissociation threshold region. At 839 A, the peak in the fluorescence cross section, one observes Lyman-..cap alpha.. emission from several continuums and from the J=1 and J=2 predissociated rotational levels of the D /sup 1/Pi/sup +//sub u/(v'=3) state. At this wavelength the branching ratio sigma (2s)/(sigma (2s)+sigma (2p)) was obtained using a quenching field method. It was determined that 57% of the excited atoms are produced in the metastable 2 /sup 2/S/sub 1/2/ state. From a study of the fluorescence signal versus pressure a cross section of 0.9 x 10/sup -14/ cm/sup 2/ was derived from the chemi-ionization reaction H/sub 2/+H(2s) ..-->..H/sup +//sub 3/+e/sup -/.