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Photoemission in the molecular frame using the vector correlation approach: from valence to inner-valence shell ionization

2004; Elsevier BV; Volume: 141; Issue: 2-3 Linguagem: Inglês

10.1016/j.elspec.2004.06.012

1873-2526

D. Dowek, M. Lebech, J. C. Houver, Robert R. Lucchese,

Photochemistry and Electron Transfer Studies

The (VA+, Ve, eˆ) vector correlation method, combining imaging and time-of-flight resolved electron-ion coincidence techniques, is used to probe dissociative photoionization (DPI) of simple molecules induced by VUV polarized synchrotron radiation, to obtain the I(θe, ϕe) molecular frame photoelectron angular distributions (MFPADs). We focus on examples where DPI is induced by valence shell and inner-valence shell excitation. For valence shell ionisation, we report the results of a complete experiment for DPI of O2 via the O2+(32Πu) ionic state, performed with a single circular polarization of the light at a photon excitation energy hν = 24.4 eV. A significant circular dichroism effect characterizes electron emission in the molecular frame. Inner-valence shell ionization induced by linearly polarized light is reported for the CO2 and N2O isoelectronic molecules selecting two specific satellite lines using light with hν ≃35eV. For both valence and inner-valence ionization, the measured MFPADs are compared with multichannel configuration interaction calculations, as well as with the prediction of a simple theoretical model of photoionization dynamics that probe the role of the initial state molecular orbital and which is presented in this special issue.