Fluorescence emission following core excitations in the water molecule
2006 (English)In: Journal of Physics B: Atomic, Molecular and Optical Physics, ISSN 0953-4075, E-ISSN 1361-6455, Vol. 39, no 5, 1101-1112 p.Article in journal (Refereed) Published
Photon-induced fluorescence spectroscopy has been used to study the fragmentation of the water molecule at the O 1s is edge. Fluorescence emission has been observed from the neutral fragments H, O and OH as well as from the ionic fragments O+ and OH+. The extracted fluorescence yields of the H Lyman-alpha emission and O 2p(3)(S-4)3p(P-3) -> 2p(3)(S-4)3s(S-3) transitions show the same structures as the total ion yield spectrum but with different relative intensities. The most intense fluorescence emission is restricted to the region of the core excitations, while above the O 1s ionization limit the signal is much weaker (in the case of H) or below the detection limit (O, OH and OH+). The fluorescence emission is concluded to follow from the following general cascade: the core-excited states decay by resonant Auger transitions, the final states reached undergo dissociation into ionic and neutral fragments, and fluorescence occurs from excited fragments. In the case of the OH (A(2)Sigma(+) -> X-2 Pi) emission, the decay of core-excited states through soft x-ray emission may also be responsible for the observed fluorescence.
Place, publisher, year, edition, pages
2006. Vol. 39, no 5, 1101-1112 p.
high-resolution photoabsorption, dispersed spectroscopy, h2o, dissociation, oh, d2o, photodissociation, photofragments, ultraviolet, radicals
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:kth:diva-5535DOI: 10.1088/0953-4075/39/5/009ISI: 000237753700014ScopusID: 2-s2.0-33244473688OAI: oai:DiVA.org:kth-5535DiVA: diva2:9932
QC 201009102006-04-052006-04-052010-11-25Bibliographically approved