Laser isotope separation of 13C: A comparative study

Parthasarathy, V.; Sarkar, S.K.; Iyer, N. V.; Rao, K. V. S. Rama; Mittal, Jai P.

doi:10.1007/bf00325223

Cited by 25 publications

(19 citation statements)

References 13 publications

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“…6), we can also more exactly calculate the product u~3 S for conditions like in the experiment from the formula u, 3 So even with the high reflection losses (1.5%) of our mirrors, we receive a remarkable gain.…”

Section: Dependence Of the Dissociation On The Number Of Transitsmentioning

confidence: 88%

“…According to (2,3), the number of transits n can be controlled by the distance L between the mirrors. If m has a common divider 6 with n, the beam leaves the cell already after n/rY passes.…”

Section: (2)mentioning

confidence: 99%

“…The most promising laser isotope separation process at present is the multiphoton dissociation of the ~3C isotope of CHC1F 2 by a pulsed CO 2 laser [1][2][3]:…”

Section: Introductionmentioning

confidence: 99%

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IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

Fuß

Göthel

Ivanenko

et al. 1994

Z Phys D - Atoms, Molecules and Clusters

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The small absorption is a major problem in isotopically selective IR multiphoton dissociation. Usually the radiation diverges before it is fully absorbed. To solve this problem, we have demonstrated the application of a refocusing (Herriott) multipass cell. It can generally help in laser isotope separation to use the photons more efficiently. Employing such a cell and a Q-switched CO2 laser at high repetition rate, the dissociation yield of CHC1F2 was 23 times higher than in a single pass. The number of passes used (up to 60) was more than is conventionally possible in such small cells. The increased number was permitted by making use of spherical aberration. With 18 passes, we also measured the multiphoton absorption for various wavelengths and pressures, in part separately for 12CHC1F2 and J3CHCll=2, and also for two-wavelength irradiation. Appropriate change of pressure or wavelength increased the absorption. But the corresponding increase of the dissociation was larger in every case. To explain this and other observations, we invoke the molecular distribution over the energy levels.

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Section: Dependence Of the Dissociation On The Number Of Transitsmentioning

confidence: 88%

Section: (2)mentioning

confidence: 99%

See 1 more Smart Citation

IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

Fuß

Göthel

Ivanenko

et al. 1994

Z Phys D - Atoms, Molecules and Clusters

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“…CF 3 Br is a well-suited target for investigation by IR laser chemistry and isotopically selective multiphoton-induced [8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

The ro-vibrational analysis of thev₄fundamental band of CF₃Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

et al. 2014

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2014) The ro-vibrational analysis of the v 4 fundamental band of CF 3 Br from jetcooled diode laser and FTIR spectra in the 8.3-µm region,The v 4 fundamental band of CF 3 79 Br and CF 3 81 Br, present in natural isotopic abundance, was investigated in the 8.3-μm region by high-resolution infrared spectroscopic techniques. Tuneable diode laser spectra were recorded in the ranges 1202.5-1205.0 cm −1 , 1208.0-1210.1 cm −1 and 1212.5-1214.5 cm −1 . The tuneable diode laser spectra were obtained at the reduced temperature of 200 K and in a free-jet expansion. The latter technique was used to reduce spectral congestion, achieving a rotational temperature of about 50 K, with a resolution up to 0.0008 cm −1 . A Fourier transform infrared spectrum covering the entire spectral region of the v 4 band, between 1190 and 1220 cm −1 , was recorded at 298 K with a resolution of 0.004 cm −1 . The experimental wavenumbers from the different spectroscopic techniques were combined to accomplish the complete ro-vibrational analysis of v 4 . In total, 4651 transitions were assigned to CF 3 79 Br, 4047 to CF 3 81 Br, with J max = K max =80; of these, 3171 for CF 3 79 Br and 2755 for CF 3 81 Br are from diode laser measurements. The data of each isotopologue were analysed using the model Hamiltonian for a degenerate vibrational state of a molecule of C 3v symmetry. The v 4 band of both the isotopologues resulted essentially unperturbed, but the l = k = ±2 l-resonance was found to be active within the v 4 = 1 state. Precise values of the vibrational energy and of the ro-vibrational parameters of v 4 = 1 for CF 3 79 Br and CF 3 81 Br were obtained. The bromine isotopic splitting amounts to 6.9 × 10 −3 cm −1 . In addition, the equilibrium geometry and the harmonic force field were calculated ab initio using the large-size basis set def2-QZVP in conjunction to the PBE0 functional.

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“…1,2) Since early observations on isotope effects by Letokhov et al, many efforts have been made for the application of IRMPD to practical isotope separation. [3][4][5][6][7][8][9][10][11][12][13][14][15] Most studies are concerned with 13 C separation by IRMPD of fluorohydrocarbons. Baranov has reported the production of enriched 12 C (atomic fraction, 99.99%; production rate, 1 g/h) by IRMPD of natural CF 3 I using a high repetition CO 2 laser.…”

Section: Introductionmentioning

confidence: 99%

High Enrichment of²⁸Si by Infrared Multiple Photon Decomposition of Si₂F₆

Yokoyama

Ohba

Shibata

et al. 2002

Journal of Nuclear Science and Technology

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High enrichment of 28 Si has been carried out using the laser isotope separation technique based on the isotopically selective infrared multiple photon decomposition of Si 2 F 6 . When about 2 Torr of Si 2 F 6 was irradiated at a fluence of 1.0 J/cm 2 per pulse with the 10P(8) line of a TEA CO 2 laser at 954.55 cm −1 , the compound decomposed very efficiently with high isotope selectivity. The products SiF 4 and white solids were enriched with 29 Si and 30 Si, while the residual Si 2 F 6 was enriched with 28 Si. The atomic fraction of 28 Si in residual Si 2 F 6 increased with increasing decomposition of Si 2 F 6 ; 99.9% of 28 Si was obtained at a consumption of 50% of initial Si 2 F 6 . The large-scale flow experiment yielded 99.7% 28 Si at a production rate of 2.5 g/h, where a mixture of 3.3 Torr Si 2 F 6 and 6.6 Torr argon was irradiated with 10P(8) laser pulses at a repetition rate of 5 Hz. Merits and demerits of the present laser separation are discussed in comparison to those of conventional separation methods. Laser enrichment of 28 Si seems promising for economical production of large quantity of pure 28 Si. Various applications of silicon isotopes are briefly reviewed.

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Laser isotope separation of 13C: A comparative study

Cited by 25 publications

References 13 publications

IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

The ro-vibrational analysis of thev₄fundamental band of CF₃Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

High Enrichment of²⁸Si by Infrared Multiple Photon Decomposition of Si₂F₆

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Laser isotope separation of 13C: A comparative study

Cited by 25 publications

References 13 publications

IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell

The ro-vibrational analysis of thev4fundamental band of CF3Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

High Enrichment of28Si by Infrared Multiple Photon Decomposition of Si2F6

Contact Info

Product

Resources

About

The ro-vibrational analysis of thev₄fundamental band of CF₃Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

High Enrichment of²⁸Si by Infrared Multiple Photon Decomposition of Si₂F₆