Computational study of (e,2e) electron momentum spectroscopy and Penning ionization electron spectroscopy for molecular nitrogen

The electron distributions of the outer valence orbitals of molecular nitro gen (N-2): 3 sigma(g), 1 pi(u) and 2 sigma(u), are studied by density funct ional method (DFT-B3LYP) calculations with the 6-31G, 6-311G, 6-311 + G, an d 6-311 + G* basis sets, as well as at the self-consistent field Hartree-Fo ck (SCF-HF) and the fourth-order Moller-Plesset (MP4) level calculations. T he results obtained at the B3LYP/6-311 + G and B3LYP/6-311 + G* levels give good descriptions for the published experimental (e,2e) electron momentum spectra (Cook et al., Chem. Phys. 141 (1990) 211), and present a reasonable interpretation to the published Penning ionization electron spectra (Hotop et al., J. Electron Spectrosc. Relat. Phenom. 16 (1979) 213; Ohno et al., J. Am. Chem. Sec. 105 (1983) 4555, etc.) for the outer valence orbitals of N-2. Here the properties of (e,2e) electron momentum spectroscopy (EMS) and Penning ionization electron spectroscopy (PIES) are compared and discussed in detail, and the interconnections between the momentum space electron di stributions observed in EMS and the exterior electron distributions observe d in PIES for outer valence orbitals of N-2 are analyzed at last. (C) 1999 Elsevier Science B.V. All rights reserved.