Auger decay of the C 1s(-1)2 pi(*) resonance in carbon monoxide: vibrationally and angularly resolved spectra

Auger electron spectra from the decay of the nu=0, 1, and 2 levels of the C 1s(-1)2 pi* state were measured with sufficiently high electron and photon energy resolution to completely resolve the vibrational structure of the f inal electronic states. The results are compared with ab initio calculation s with emphasis on the analysis of the spectator Auger transitions. The ani sotropy parameters extracted from angle-resolved spectra show variations wi thin the vibrational envelopes of the participator Auger decay and exhibit a complex oscillating behavior for the spectator Auger transitions. In addi tion, two-dimensional (2D) imaging of the electron emission across the C 1s (-1)2 pi* resonance was performed. The ratio of resonant and nonresonant io nization processes is estimated from the 2D map. Strong vibrational lifetim e interference effects apparent in the 2D imaging are discussed. (C) 1999 A merican Institute of Physics. [S0021-9606(99)00741-2].