title: Threshold-photoelectron-spectroscopy-coincidence study of the double photoionization of HBr.
abstract: A threshold-photoelectron-coincidence spectrum of HBr has been recorded in the 32.2-35.8 eV photon energy range, with a resolution of approximately 0.01 eV, using a synchrotron radiation source. The X (3)Sigma(-) and a (1)Delta(2) states of the HBr(2+) dication are clearly observed in the spectrum, while there is no clear evidence for the formation of the b (1)Sigma(+) electronic state. For the first two states, the vibrational states v=0-3 have been resolved, while for the ground X (3)Sigma(-) state also spin-orbit splitting has been detected. The results appear in good agreement with previous experimental observations. A comparison with theoretical predictions indicates the role of "noncovalent" contributions to the interaction between the two atomic partners for the formation of metastable states.
authors.affiliation: ISMN-CNR Sez.Roma 1, P.le A. Moro 5, 00185, Rome, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Alagia
authors.forename: Brunetto G
authors.initials: BG
authors.lastname: Brunetti
authors.forename: Pietro
authors.initials: P
authors.lastname: Candori
authors.forename: Stefano
authors.initials: S
authors.lastname: Falcinelli
authors.forename: Marc Moix
authors.initials: MM
authors.lastname: Teixidor
authors.forename: Fernando
authors.initials: F
authors.lastname: Pirani
authors.forename: Robert
authors.initials: R
authors.lastname: Richter
authors.forename: Stefano
authors.initials: S
authors.lastname: Stranges
authors.forename: Franco
authors.initials: F
authors.lastname: Vecchiocattivi