Enrichment of silicon isotopes with infrared free-electron laser radiation
- Los Alamos National Lab., NM (United States)
- National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)
The authors have used the FELIX infrared free-electron laser (FEL) at the FOM Institute for Plasma Physics in The Netherlands to enrich silicon isotopes by multiple-photon dissociation of the molecule Si{sub 2}F{sub 6}. The absorption of infrared radiation induces the reaction is{sub 2}F{sub 6} {r_arrow} SiF{sub 4} + SiF{sub 2}. Much of the SiF{sub 2} product further reacts to form additional SiF{sub 4}. The Si{sub 2}F{sub 6} molecule has absorption bands in the 10, 12, and 25 {micro}m spectral regions. FEL-induced reactions occurred in all three regions. The reaction fraction was highest for the stronger band in the 10 {micro}m region. Reactions in all three bands were isotopically selective. Irradiation in the 10 {micro}m region at 952 cm{sup {minus}1} gave an isotopic selectivity of 5.6 for {sup 30}Si. For comparison, the published isotopic selectivity using a CO{sub 2} laser in the same spectral region is in excess of 17. The authors attribute the lower selectivity obtained with an FEL to its longer macropulse, its broader spectral width, and differences in experimental procedure. FEL irradiation in the region of the 12 {micro}m band produced isotopic selectivities in excess of 20 for {sup 30}Si. Selective production of {sup 28}Si was high in the 25 {micro}m region. The authors used changes in the infrared spectra of the irradiated samples for all analyses of reaction and isotope enrichment except for a single confirmation of enrichment with a mass spectrometer.
- OSTI ID:
- 351564
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 21 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
- Country of Publication:
- United States
- Language:
- English
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