Berlin 2001 – wissenschaftliches Programm
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MO: Molekülphysik
MO 8: Posters Thursday: Dissociation and other Collision Processes
MO 8.9: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Vector correlations in dissociative photoionization of simple molecules. — •M. Lebech1, A. Lafosse1, J. C. Brenot1, P. M. Guyon1, J. C. Houver1, D. Dowek1, and R. Lucchese2 — 1Laboratoire des Collisions Atomiques et Moléculaires, Bât 351, Université Paris-Sud, 91405 Orsay, France — 2Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, USA
The (VX+→, Ve→, P→) vector correlation method developed for the study of dissociative photoionization of simple molecules induced by VUV linearly polarized synchrotron radiation (P→) (Super ACO, LURE):
XY + hν (P→) → (XY)** → X+ + Y* + e
consists in measuring the VX+→ and Ve→ nascent ion and electron velocity vectors for each event [1]. It combines position sensitive detection and time-of-flight resolved coincidence techniques.
The magnitudes of the VX+→ and Ve→ vectors provide the ion-electron kinetic energy correlation, which identifies the pathway for each process and determines their branching ratios. The complete 3D angular distribution I(χ X+,θ e,φ e), where χ X+ is the polar angle of VX+→ referred to P→, and θ e and φ e are the polar and azimuthal electron emission angles in the molecular frame, is derived from the spatial analysis of the (VX+→, Ve→, P→) correlation. It characterizes e.g. the symmetry of the (XY)** state and the electronic wave function in the continuum. The method will be illustrated by recent results for photoionization of NO [1], H2, N2O, CO2 ..., and compared with theoretical results in the case of NO [2].
[1] A. Lafosse et al, Phys. Rev. Lett. 84 5987 (2000)
[2] R. Lucchese et al, in preparation