Total cross sections and molecular frame photoelectron angular distributions in the N 1s photoionization of N2:: An investigation of electron correlation effects

Multichannel scattering calculations have been performed to study the electron correlation effects in the N 1s photoionization of nitrogen molecules. Both the Hartree-Fock and configuration-interaction methods were applied in the calculations of target states, therefore the role of electron correlation effects in the target states can be investigated. Both single- and multichannel calculations have been performed to study the interchannel coupling effects. With correlated target states and coupled channels in the calculations, our calculated cross sections and asymmetry parameters are in good agreement with the experiments. The shape resonance is very well reproduced in our calculation, and we found weak coupling between channels leading to the 1sigma(g)(-1) and 1sigma(u)(-1) states, which agrees well with more recent experimental results by Hergenhahn [J. Phys. Chem. 105, 5704 (2001)], but contradicts the random phase approximation results. The molecular frame photoelectron angular distributions obtained from our calculations are also in agreement with experiments. Our calculations also suggest an autoionization process via a double-excited state of the character of 1sigma(g)(-1)1pi(u)(-1)1pi(g)(2), which is located near the threshold as observed by the experiments. Dynamics of the shake-up channels are also studied and compared with the experiments. (C) 2002 American Institute of Physics.