The binding energy spectrum and electron momentum profiles of the inner orbitals of methyl iodide have been measured using an electron momentum spectrometer at the impact energy of 1200 e V plus binding energy.Two peaks in the binding energy spectrum,arising from the spin-orbit splitting,are observed and the corresponding electron momentum profiles are obtained.Relativistic density functional calculations are performed to elucidate the experimental electron momentum profiles of two spin-orbit splitting components,showing agreement with each other except for the intensity in low momentum region.The measured high intensity in the low momentum region can be further explained by the distorted wave calculation.
The binding energy spectra and electron momentum distributions for the outer valence molecular orbitals of gaseous 2-fluoroethanol have been measured by the non-coplanar asym- metric （e, 2e） spectrometer at impact energy of 2.5 keV plus binding energy. The quantitative calculations of the ionization energies and the relevant molecular orbitals have been carried out by using the outer-valence Green＇s function method and the density functional theory with B3LYP hybrid functional. The observed ionization bands in binding energy spectra, as well as the previous photoelectron spectrum which was not assigned, have been assigned for the first time through the comparison between experiment and theory. In general, the the- oretical electron momentum distributions calculated by B3LYP method with aug-cc-pVTZ basis set are in line with the experimental ones when taking into account the Boltzmann- weighted thermo-statistical abundances of five conformers of 2-fluoroethanol.
