Study of outer valence orbitals of carbon dioxide by (e, 2e) spectroscopy

Abstract

Abstract By using symmetric non-coplanar electron momentum spectroscopy at impact energy of 1200 eV plus binding energy, valence shell binding energy spectra of carbon dioxide have been obtained. The experimental momentum profiles of four outer valence orbitals: 1π g , 1π u , 3σ u , 4σ g are compared with theoretical profiles calculated by Hartree–Fock and density functional theory (DFT-B3LYP) methods using both 6-311++G* and double-zeta basis sets. The experimental results are in good agreement with the calculated results. A minimum at p≈1.2 a.u. for the 3σ u orbital is found. The experimental momentum profiles generally agree better with the profiles calculated by the DFT method than those by the HF method. The position and momentum space density maps for four outer valence orbitals of CO 2 are also presented.