M series resonant x-ray lines of barium for near threshold electron excitation
An investigation of the M series resonant x-ray emission lines of barium for near threshold electron excitation was undertaken with a vacuum double crystal spectrometer equipped with potassium acid phthalate crystals. X-ray continuum isochromats were obtained for barium samples using the double crystal spectrometer as a monochrometer set to pass 532 eV photons. The rotatable anode allowed the samples to be observed by either the double crystal spectrometer or a soft x-ray appearance potential spectrometer, which was used for monitoring the surface of the varium sample for contamination, and to provide a cross-check for the double crystal spectrometer data. Barium M series characteristic x-ray spectra for 2.0 keV electron excitation were obtained for a variety of samples, and it was discovered that the fluorescent and resonant x-ray emission line energies remained virtually the same, regardless of the chemical condition of the sample. The continuum resonance effect was observed for near-threshold energy electron excitation, but it was significantly weaker than the same effect observed previously for lanthanum or cerium. The electron excitation energy and intensity of this effect were strongly dependent on the chemical condition of the barium sample. X-ray continuum isochromats were observed for pure and contaminated barium samples at a photon energy of 532 eV. For pure metallic barium, a peak associated with 4f electronic states was observed at an energy of about 10.2 eV above the Fermi level. When the sample was exposed to 1.5 x 10[sup 4] Langmuir of air, the 4f structure became more sharply peaked, and shifted to an energy of about 12.0 eV above the Fermi level. A continuum isochromat of barium oxide was also observed. Chemical shifts in barium M[sub IV] and M[sub V] appearance potential spectra are therefore caused soley by shifts in the energy position of the empty 4f electronic states relative to the Fermi level.
- Research Organization:
- New Mexico State Univ., Las Cruces, NM (United States)
- OSTI ID:
- 7295935
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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BARIUM
M SHELL
X-RAY EMISSION ANALYSIS
ENERGY-LEVEL TRANSITIONS
F STATES
ALKALINE EARTH METALS
CHEMICAL ANALYSIS
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY LEVELS
METALS
NONDESTRUCTIVE ANALYSIS
664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-)