An electron momentum spectroscopy investigation on the 1a′ inner valence orbital of cyclopentene

The ionization energy spectrum and the spherically averaged momentum distribution of 1a′ inner valance orbital for cyclopentene have been investigated by using a high resolution (ΔE=1.15eV, Δp≈0.1a.u.) electron momentum spectrometer. The impact energy was 1200eV plus binding energy (i.e. 1202—1234eV) and a symmet ric non-coplanar kinematics was employed. The experimental momentum profile of the 1a′ inner valence orbital is obtained and compared with the theoretical m omentum distributions calculated by using Hartree-Fock and density functional th eory methods with the basis sets STO-3G, 6-31G, 6-311++G** and au g-cc-pVTZ. The pole strength of the 1a′ inner valence orbital is estimated and the electron correlation effects are discussed.