A photoelectron spectroscopy study of the valence shell photoionization dynamics of acetylene (vol 97, pg 253, 1998)

The valence shell photoionization dynamics of acetylene have been studied i n the photon energy range 13-140 eV using photoelectron spectroscopy and sy nchrotron radiation. Photoelectron angular distributions and branching rati os have been determined for the X (2)Pi(u), A (2)Sigma(g)(+) B (2)Sigma(u)( +) and C (2)Sigma(g)(+) single-hole ionic states and for two inner valence correlation states. An interpretation of the experimental results was carri ed out based upon previous theoretical predictions, and it appears that the photoionization dynamics are being strongly affected by shape resonance ph enomena. The photoelectron asymmetry parameters associated with the A (2)Si gma(g)(+) and the C (2)Sigma(g)(+) ionic states provide the first experimen tal confirmation of the predicted a, continuum shape resonance. (C) 1999 El sevier Science B.V. All rights reserved.