The multiphoton ionization of uranium hexafluoride. Revision 1

Thesis/Dissertation · Fri May 01 04:00:00 EDT 1992

DOI:https://doi.org/10.2172/10142145· OSTI ID:10142145

Armstrong, Donald P. ^[1]

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1. Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)

Multiphoton ionization (MPI) time-of-flight mass spectroscopy and photoelectron spectroscopy studies of UF₆ have been conducted using focused light from the Nd:YAG laser fundamental (λ=1064 nm) and its harmonics (λ=532, 355, or 266 nm), as well as other wavelengths provided by a tunable dye laser. The MPI mass spectra are dominated by the singly and multiply charged uranium ions rather than by the UF_x⁺ fragment ions even at the lowest laser power densities at which signal could be detected. The laser power dependence of Uⁿ⁺ ions signals indicates that saturation can occur for many of the steps required for their ionization. In general, the doubly-charged uranium ion (U²⁺) intensity is much greater than that of the singly-charged uranium ion (U⁺). For the case of the tunable dye laser experiments, the Uⁿ⁺ (n = 1- 4) wavelength dependence is relatively unstructured and does not show observable resonance enhancement at known atomic uranium excitation wavelengths. The dominance of the U²⁺ ion and the absence or very small intensities of UF_x⁺ fragments, along with the unsaturated wavelength dependence, indicate that mechanisms may exist other than ionization of bare U atoms after the stepwise photodissociation of F atoms from the parent molecule.

• Research Organization: Oak Ridge K-25 Site, TN (United States). UEO Enrichment Technical Operations Div.; Oak Ridge National Lab., TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84OT21400; AC05-76OR00001
• OSTI ID: 10142145
• Report Number(s): K/ETO--96-Rev.1; ON: DE92013383
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702
664400
74 ATOMIC AND MOLECULAR PHYSICS
DISSOCIATION
DYE LASERS
EXCITED STATES
EXPERIMENTALLY DERIVED INFORMATION ON ATOMIC AND MOLECULAR PROPERTIES
MASS SPECTROSCOPY
MULTI-PHOTON PROCESSES
MULTICHARGED IONS
NEODYMIUM LASERS
PHOTOELECTRON SPECTROSCOPY
PHOTOIONIZATION
PROPERTIES OF RADIOACTIVE MATERIALS
TIME-OF-FLIGHT SPECTROMETERS
URANIUM HEXAFLUORIDE