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Laser-induced migration and isotope separation of epi-thermal monomers and dimers in supercooled free jets

Published online by Cambridge University Press:  07 June 2005

JEFF W. EERKENS
JEFF W. EERKENS
Affiliation:
CRISLA Research Laboratory, Nuclear Science and Engineering Institute, University of Missouri, Columbia, Missouri
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Abstract

Explicit relations are developed to estimate the outflux of migrating isotopomers iQF6 to the outskirts of a supersonic supercooled free jet whose core is irradiated by a co-axial laser beam and intercepted by a skimmer that separates core gas from peripheral gases. The QF6 target gas is diluted in carrier gas G (G = He, N2, Ar, Xe, SF6, etc.) which determines the jet's supersonic characteristics and forms QF6:G dimers at low temperatures. Under isotope-selective laser excitation, excited iQF6* convert their vibrational energy V into kinetic energy T after forming transient iQF6*:G dimers that dissociate in sub-microseconds. Three migrating groups with different transport parameters are created in the jet: thermal monomers, faster-moving epithermal monomers, and slower-moving dimers. Jet-core-fleeing QF6 is enriched in iQF6 due to enhanced outwards migration of iQF6! epithermals and reduced escape of jQF6:G dimers in the jet. Isotope enrichments in the rim gases are highest for heavier carrier gases such as G = Xe or G = SF6.

Keywords

Epithermal moleculesLaser isotope separationMonomer versus dimer migration ratesSF6 and UF6Supersonic free jets
Type
Research Article
Information
Laser and Particle Beams , Volume 23 , Issue 2 , June 2005 , pp. 225 - 253
Copyright
2005 Cambridge University Press

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References

REFERENCES

Adamson, T.C. & Nichols, J.A. (1959). On the structure of jets from highly underexpanded nozzles into still air. J. Aerospace Sciences 1, 23.Google Scholar
Benedict, M., Pigford, T.H. & Levi, H. (1981). Nuclear Chemical Engineering, 2nd Edition, New York, McGraw-Hill.
Bernstein, L.S. & Kolb, C.E. (1979). Understanding the IR continuum spectrum of the N2O dimer and other VanderWaals complexes at low temp's. J. Chem. Phys. 71.Google Scholar
Beswick, J.A. & Jortner, J. (1978). Perpendicular vibrational predissociation of t-shaped VanderWaals molecules. J. Chem. Phys. 69, 512.CrossRefGoogle Scholar
Beu, T.A. & Takeuchi, K. (1995). Structure and IR-spectrum calculations for small SF6 clusters. J. Chem. Phys. 103, 6394.CrossRefGoogle Scholar
Beu, T.A., Onoe, J. & Takeuchi, K. (1997). Calculations of structure and IR-spectrum for small UF6 clusters. J. Chem. Phys. 106, 5910.CrossRefGoogle Scholar
Burak, I., Houston, P., Sutton, D.G. & Steinfeld, J.I. (1970). Observation of laser-induced acoustic waves in SF6. J. Chem. Phys. 53, 9.CrossRefGoogle Scholar
Chow, R.R. (1959). On the separation of a binary gas mixture in an axisymmetric jet. Tech Report HE-150-175 (Series 110, Issue No. 5) University of California-Berkeley, Institute of Engineering Research.
Eerkens, J.W. (1957a). Design considerations and region of operation of the jet diffusion equipment. Tech Report HE-150-158 (Series 110, Issue No. 3) University of California-Berkeley, Institute of Engineering Research.
Eerkens, J.W. & Grossman, L.M. (1957b). Evaluation of the diffusion equation and tabulation of experimental gaseous diffusion constants. Tech Report HE-150-150 (Series 110, Issue No. 1). University of California-Berkeley, Institute of Engineering Research.
Eerkens, J.W., Sehgal, B. & Grossman, L.M. (1958). Some preliminary results on the separation of gaseous components in a jet. Tech Report HE-150-162 (Series 110, Issue No. 4). University of California-Berkeley, Institute of Engineering Research.
Eerkens, J.W. (1973). Model equations for photon emission rates and absorption cross-sections (Rocket Radiation Handbook Volume II), USAF-FTD-CW-01-01-74, AD-A007946.
Eerkens, J.W., Kunze, J.F. & Anderson, G. (1995). Mo-98 and Mo-99 laser isotope separation for nuclear medicine. Proc. Missouri Ac. of Science, Eng'ng Section.
Eerkens, J.W., Miller, W.H. & Puglisi, D. (1996). Laser separation of medical isotopes—QF5Cl Spectra. ANS Transactions of Nov. 11–14>, 1996, Washington DC Meeting.
Eerkens, J.W. (1998). Separation of isotopes by laser-assisted retardation of condensation (SILARC). Laser Part. Beams 16, 295.CrossRefGoogle Scholar
Eerkens, J.W. (2001a). Equilibrium dimer concentrations in gases and gas mixtures. Chem. Phys. 269, 189.Google Scholar
Eerkens, J.W. (2001b). Average diffusion-to-the-wall times for laser-tagged molecules in a long cylinder. Appl. Phys. B 72, 885.Google Scholar
Eerkens, J.W. (2003). Nucleation and particle growth in supercooled flows of SF6/N2 and UF6/N2 mixtures. Chem. Phys. 293, 111–153.CrossRefGoogle Scholar
Eerkens, J.W. (2005). Condensation reduction and isotope separation of laser-excited molecules in wall-cooled subsonic gas streams, Nucl. Sci. Eng. 150, 1–22.Google Scholar
Geraedts, J., Setiadi, S., Stolte, S. & Reuss, J. (1981). Laser induced predissociation of SF6 clusters. Chem. Phys. Let. 78, 277.CrossRefGoogle Scholar
Geraedts, J., Stolte, S. & Reuss, J. (1982). Vibrational predissociation of SF6 dimers and trimers. Z. Physik A 304, 167–175.CrossRefGoogle Scholar
Glasstone, S. & Edlund, M.C. (1952). The elements of nuclear reactor theory, Chapter 6; New York: Van Nostrand.
Herzberg, G. (1945). Infrared and raman spectra, New York: Van Nostrand.
Hirschfelder, J.O., Curtiss, C.F. & Bird, R.B. (1967). Molecular Theory of Gases and Liquids. Footnote on page 555 of Section 4a. John Wiley, New York, Fourth Printing 1967.
Kim, K.C. & Person, W.B. (1981). Study of absolute IR intensity of v3 absorption of UF6. J. Chem. Phys. 74, 171.CrossRefGoogle Scholar
Kraus, M. (1967). Compendium of ab initio Calculations of Molecular Energies and Properties, National Bureau of Standards, Technical Note NBS TN 438, Dec 1967, US Government Printing Office, Washington DC.
Lee, Y.T. (1977). Isotope separation by photodissociation of VanderWaals molecules. U.S. Patent 4,032,306, issued June 1977.
Liedenbaum, C., Heijmen, B., Stolte, S. & Reuss, J. (1989). IR predissociation of halogenated methane VanderWaals complexes. Z. Physik D 11, 175–180.Google Scholar
Liepmann, H.W. & Puckett, A.E. (1953). Introduction to Aerodynamics of a Compressible Fluid, Ronald Press.
McCafferey, A.J. & Marsh, R.J. (2002). Vibrational predissociation of vanderWaals molecules; An internal collision, angular momentum model. J. Chem Phys. 117, 9275.CrossRefGoogle Scholar
Schwartz, R.N., Slawski, Z.I. & Herzfeld, K.F. (1952). Calculation of vibrational relaxation times in gases. J. Chem. Phys. 20, 159.CrossRefGoogle Scholar
Schwartz, R.N. & Herzfeld, K.F. (1954). Vibrational relaxation times in gases (three-dimensional treatment). J. Chem. Phys. 22, 5.CrossRefGoogle Scholar
Smalley, R.E., Levy, D.H. & Wharton, L. (1976). The fluorescence excitation spectrum of the HeI2 VanderWaals complex. J. Chem. Phys. 64, 3266.CrossRefGoogle Scholar
Snells, M. & Reuss, J. (1987). Induction effects on IR-predissociation spectra of (SF6)2, (SiF4)2, and (SiH4)2. Chem. Phys. Let. 140, 543.CrossRefGoogle Scholar
VanBladel, J.W.I. & VanderAvoird, A. (1990). The infrared photodissociation spectra and the internal mobility of SF6, SiF4, and SiH4 dimers. J. Chem. Phys. 92, 2837.CrossRefGoogle Scholar
VandenBergh, H. (1985). Laser assisted aerodynamic isotope separation,” Laser und Optoelektronik 3, 263.Google Scholar
Yardley, J.T. (1980). Introduction to Molecular Energy Transfer, Academic Press, New York