Yuan Zhen-Sheng

Inner-Shell Excitations of 2p Electrons of Argon Investigated by Fast Electron Impact with High Resolution

Electron energy loss spectra of inner-shell excitations of 2p electrons of argon are measured at an incident electron energy of 2500 eV and scattering angles of 0° and 4°. The dipole-forbidden transitions of 2p−13/24p and 2p−13/25p are observed in the measured spectra and assigned based on the calculations of the Cowan code. The positions and line widths for the excitations of 2p−13/2nl and 2p−11/2nl (n ≤ 5) of argon are determined. The present results show that the line widths of the electric quadrupole transitions of 2p−13/24p[5/2 + 3/2]2 and the electric monopole one of 2p−13/24p[1/2]0 are less than those of the dipole-allowed transitions.

Experimental and theoretical investigations of absolute optical oscillator strengths for valence excitations of nitric oxide

The absolute optical oscillator strength density spectra of nitric oxide in the energy region of 5.0-22.0 eV have been measured by a high-resolution fast-electron energy loss spectrometer. With the calculated results obtained by the multiscattering self-consistent-field method and channel characteristics, the strongly overlapped spectra in the energy region of 7.5-9.3 eV have been analysed and the corresponding partially vibrationally resolved optical oscillator strengths have been estimated from the experimental spectra.

Generalized oscillator strengths for some higher valence-shell excitations of krypton atom

The valence-shell excitations of krypton atom have been investigated by fast electron impact with an angle-resolved electron-energy-loss spectrometer. The generalized oscillator strengths for some higher mixed valence-shell excitations in 4d, 4f, 5p, 5d, 6s, 6p, 7s ← 4p of krypton atom have been determined. Their profiles are discussed, and the generalized oscillator strengths for the electric monopole and quadrupole excitations in 5p ← 4p are compared with the calculations of Amusia et al. (Phys. Rev. A 67 022703 (2003)). The differences between the experimental results and theoretical calculations show that more studies are needed.

Absolute oscillator strength densities below 100eV of N2

The absolute optical oscillator strength density (OOSD) and generalized oscillator strength densities (GOSDs) below 100eV of N2 are determined with an incident electron energy of 2500eV and an energy resolution of 100 meV. The absolute generalized oscillator strengths (GOSs) for two transitions to the superexcited states at 23 and 31.4eV are determined and their momentum transfer dependence behaviours are discussed.

Superexcited states of carbon monoxide studied by fast-electron impact

Absolute optical oscillator strength density and double differential cross section spectra of CO below 120 eV are determined by fast electron impact. Some peaks above the first ionization threshold stand out as the momentum transfer square K2 increases. The doubly excited Rydberg states converging to C 2Σ+, D 2Π and F 2Π states of CO+, respectively, are confirmed in our spectra. Another peak at around 32 eV is assigned to the transition of (3σ)−1(2π)1 1Π← X1Σ+.

Optically Forbidden Excitations of 3s Electron of Argon by Fast Electron Impact

The electron energy loss spectrum of argon in the energy region of 24.5-30.5 eV was measured at 2.5 keV impact energy. The line profile parameters of the optically forbidden excitations of 3s-1ns (n = 4-6) and 3s-1nd (n = 3-7) of argon, i.e., Eγ, Γ,q and µ, were determined.

Photoabsorption Spectrum and Optically Forbidden Transitions of Krypton by Electron Impact

A high resolution fast electron energy loss spectrometer with multi-channel energy analysis was employed. The maxima just above the threshold 4p-1(2P1/2), which is regarded as a shape resonance, was obtained at 16.3 eV. The optically forbidden excitations of 4s electron were measured for the first time, and the energy positions are 23.75 eV (4s-15s), 25.66 eV (4s-16s/4d) and 26.60 eV (4s-17s/5d).