Nondipole effects in molecular nitrogen valence shell photoionization

Nondipole photoelectron parameters have been obtained experimentally for the outer-valence 3 sigma(g), 1 pi(u) and 2 sigma(u) shells in molecular nitrogen from threshold to similar to 200eV photon energy. Significant nondipole effects are observed even in the immediate threshold regions of these valence-shell distributions. The results of preliminary calculations for the 3 sigma(g) and 2 sigma(u) clarify the origins of the observed features in terms of contributing molecular symmetry channels. Theory and experiment are in excellent accord, suggesting that the large nondipole effects previously observed in atoms and the K-shells of molecules can also appear at low photon energies in the outer-valence shells of molecules. (c) 2005 Elsevier B.V. All rights reserved.