Selective excitation of the npσ1Σu+ and npπ1Πu to E,F 1Σg+ emission systems in molecular hydrogen using synchrotron radiation

The npσ1Σu+ and npπ1Πu states in H2 have been selectively excited using monoenergetic synchrotron light in the range 14.4–15.5 eV and the subsequent emission was observed using a grating spectrometer. In total 22 well separated bands of the npσ1Σu+ and npπ1Πu to E,F 1Σg+ systems (n=3–7) were observed and rotationally analysed. The intensities of the P and R branches relative to the Q branch vary strongly in the npπ to EF bands confirming the existence of predissociations of a large number of npπ1Π+ levels. Energy levels of the E,F 1Σg+ state (vE,F=0, 1, 3, 6–10) are obtained which confirm earlier determinations from other H2 experiments.