Electron-impact study in valence and autoionization resonance regions of argon

Abstract

The recently built electron-energy-loss spectrometer (EELS) (typical FWHM 60 meV) was employed to measure the EELS spectra of argon in the discrete and autoionization resonance regions at a 2.5-keV impact energy and a mean scattering angle of O'. Relative differential optical oscillator strength spectra were established by multiplying the EELS spectra by the known Bethe-Born conversion factor of the spectrometer, and were normalized at a single point in the smooth continuum using the absolute values reported by Chan et al. [Phys. Rev. A 46, 149 (1992)]. The absolute oscillator strengths corresponding to these energy regions are reported and compared with previously published experimental and theoretical values. The values of parameters q, p, E", and I for autoionization resonances involving states 3s3p np 'P, (n =4, 5, and 6) have been determined.

Multiconfigurational Hartree-Fock close-coupling ansatz: Application to the argon photoionization cross section and delays

“…Table II lists the parameters for some of the 3s3p 6 np autoionizing states computed with our method, in length and velocity gauges, and compares them to Refs. [29,38]. Our results are generally consistent with those obtained with the R-matrix method [29] with similar choices for the computational model and basis.…”

“…IV. Argon provides a good benchmark because it is comparatively light, so a nonrelativistic description is appropriate, and its resonance profiles and angular distribution, which encode the full information about the complex partial amplitudes [34], have been the target of many experimental and theoretical studies [11,29,[35][36][37][38][39][40][41]. Figure 1 is a diagram of the levels of neutral argon accessible through one-photon transition, shown on an energy scale corresponding to photoionization from the ground state.…”

Spectroscopic Parameters of Neutral Argon Atom

“…The obtained results confirmed the fact that F l and F v are of the same order despite the fact that they are calculated in different gauge. On the other hand, our theoretically obtained results of the oscillator strength for the levels 3d[1/2]1 is compared with those obtained by other researcher either experimentally [31][32][33][34] or theoretically [35,36]. Table II shows these comparisons.…”

Superexcited states ofNOstudied by angle-resolved electron-energy-loss spectroscopy

“…Then, the spectrum measured at a mean angle of 0°was converted into relative OOSD spectrum by multiplying the Bethe-Born conversion factor of the spectrometer [17,20]. The spectra at other scattering angles were converted into relative GOSD spectra according to Eq.…”

“…[17][18][19]. Briefly, it consists of an electron gun, a hemispherical electrostatic monochromator made of aluminum, a rotable energy analyzer of the same type, an interaction chamber, a number of cylindrical electrostatic lenses, and a one-dimension position-sensitive detector for detecting the scattered electrons.…”