Electron momentum spectroscopy studies on ring compounds. I. Benzene

Abstract

The complete valence shell electron separation energy spectra and momentum distributions are measured for benzene by electron momentum spectroscopy at a total energy of 1200 eV. The measured momentum distributions are compared with those calculated in the plane wave impulse approximation (PWIA) formalism using a (9s5p/4s1p) to (4s2p/2s1p) Gaussian basis set. The level of agreement between the measured momentum distributions and the PWIA-SCF orbital momentum distributions is, in general, surprisingly good, particularly given the restricted nature of the current SCF basis set. The inner valence 2e2g, 2e1u and 2a1g orbitals are severely split by final state correlation effects. The agreement between the measured and Green function many-body method calculated spectroscopic factors and separation energies is good, although the measured separation energy spectra contain significant strength up to 51 eV, this strength being mainly of 2e1u and 2a1g origin.

Intramolecular interactions of L‐phenylalanine: Valence ionization spectra and orbital momentum distributions of its fragment molecules

“…37,66 The simulated HOMO MDs of benzene (dash lines) agree well with the experimental MDs measured by the EMS. 37,66 The other experimentally resolved valence orbital of benzene, 1a 2u , is also in good agreement with the simulated distributions except for the single point at the $78 (again the dash line) in this figure.…”

“…35,36 Here,p is the momentum of the target electron at the instant of ionization. EMS experimental conditions of benzene, 37 that is, the impact energy given by 1200 eV (plus binding energies), the effects of the finite acceptance angles of the experimental spectrometer in both y and / given by Dy 5 60.78 and D/ 5 61.98, are incorporated in the simulation with the Gaussian method. 19 Dyson orbitals of the ground state open-shell molecules can be approximated by the corresponding Hartree-Fock orbitals 38 and the Kohn-Sham (KS) orbitals in ground electronic states.…”

Double and Triple Differential Cross Sections for Single Ionization of Benzene by Electron Impact

“…This is because for ionization in a binary collision, the ejected electron carries the initial bound state momentum to which the momentum transferred in the collision is added. The uppermost three valence orbitals of benzene have π -character with amplitude minima at zero momentum [ 30 ]. As a result, a minimum in the cross section along is also expected for the so-called Bethe ridge condition where the absolute value of the ejected electron momentum p 2 is close to the magnitude of the momentum transfer q .…”

Investigation of valence orbitals of propene by electron momentum spectroscopy

“…Previous literatures 18,11 usually summed the experimental flux at all measured angles for all the outer-valence states, and then normalizing this to the corresponding sum for the result of the calculation. Previous literatures 18,11 usually summed the experimental flux at all measured angles for all the outer-valence states, and then normalizing this to the corresponding sum for the result of the calculation.…”