We report here the first measurements of momentum profiles for the propane (C3H8)valence orbitals using high resolution (△E=0.9 eV FWHM, △p=0.1 a.u.) (e,2e) electron momentum spectrometer. The impact energy was 1200 eV with binding energy l206 to 1232 eV andsymmetric non-coplanar kinematics was employed. The inner-valence spectrum is in agreementwith published photoelectron data. Excited ionic states corresponding to many-body electron correlation processes were observed for propane above 25 eV. The expeyimental momentum profileswere compared with calculations obtained using Hartree-Fock method with the minimum basis setand a high-level basis set, and also using density functional theory (DFT) local density and nonlocal density methods with a high level basis set. The agreement between theory and experimentfor the shape of orbital electron momentum distributions is generally good.
The frontier molecular orbitals （HOMO and NHOMO） of CF2BrCl molecule have been firstly investigated by （e,2e） electron momentum spectroscopy. The experimental momentum profiles are compared with the theoretical profiles employing Hartree-Fock and density functional theory with 6-31G and 6-311+G（d） basis sets. Both HF and DFT calculations using 6-311+G（d） basis set can well describe the experiment, whereas those calculated using 6-31G basis set largely underestimate the experiment at the low momentum region. Furthermore, orbital electron density images show that HOMO and NHOMO have a mixed character of the bromine and chlorine lone pairs.
This paper reports the measurements of valence electron structure for the iso-butane (iso-C4H10) using high resolution （E = 0. 9eV FWHM, p = 0.1a. u） （e, 2e） spectrometer. The impact energy was 1200 eV plus binding energy （i. e. 1205 to 1230 eV） and symmetric non-coplanar kinematics was employed. The experimental momentum Profiles have been compared with those calculated using Hartree -Fock method and Density Funchon Theory.
The electronic structure of methane has been studied in detail by the high Performance energy multichannel electron momentum spectrometer developed recently. The accurate electron momentum distributions of the It2 and 2a1 valence.orbitals of methane are measured. Excellent,agreernent can be found between the experimental data and the calculittions using the HartreeFock method and CI method with the 146-GTO basis functions. In the inner valnce regionclearly satellite structures of the 2a1 orbita1 are observed. The experimental binding energiesand pole strengths are compared with the result, of 2ph-TDA Green function’s calculation. EMSmeasurements and the 2ph-IDA calculation can give The consistent values of binding energies,while the 2ph-TDA calculation is found to overestimate the mam peak intensity of 2a1 orbit,andmderestimate the intensity of satallite structures.
