title: The angularly resolved O 1s ion-yield spectrum of O2revisited.
abstract: The high-resolution photoabsorption spectrum of O2below the O 1sσ-1ionization threshold has been reanalyzed by using a sophisticated fit approach. For the vibrational substates of the O 1sσu-1(4∑u-)3sσg(3∑u-) Rydberg state Fano lineshapes are observed indicating an interaction with the O 1sσg-1(4∑g-)3σu∗(3∑u-) core-to-valence excited state. In the angularly resolved ion-yield spectrum recorded at 90° relative to the polarization direction of the synchrotron radiation clear evidence for the O 1sσg-1(2∑g-)3σu∗(3∑u-) and the O 1sσu-1(2∑u-)3sσg(3∑u-) state was found. This observation clearly suggests thatΛ, the projection of total orbital angular momentum on the molecular axis, is not well separated in the angularly resolved ion-yield spectrum due to a partial breakdown of the axial-recoil approximation for these transitions.
authors.affiliation: Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin-Dahlem, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Püttner
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ueda