Laser separation of carbon isotopes by two-frequency dissociation of Freons

Evseev, A. V.; Laptev, V. B.; Puretskiĭ, A A; Ryabov, E. A.; Furzikov, N. P.

doi:10.1070/qe1988v018n03abeh011527

Cited by 12 publications

(7 citation statements)

References 2 publications

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“…Such an increase was observed for the collision partners Ar [-2, 4], N 2 [2,3], CHC1F2 [2,3,5] and in this work for CHC1F2 and He ( Fig. These peaks consist of transitions of the few populated rotational states to various vibrational states (e.g.…”

Section: Rotational Relaxation In Excited Statessupporting

confidence: 75%

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Isotope selective dissociation of CHClF2 by a one- and two-wavelengthQ-switched CO2 laser

Fuß

Göthel

Ivanenko

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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13C isotope separation by multiphoton dissociation of CHC1F2 was studied by a continous-discharge CO2 laser Q-switched at 8 kHz. This laser can easily emit two or more wavelengths with good spatial and temporal overlap. The best irradiation results were obtained by the line pair 9P16 + 9P28. After optimizing also the pressures of CHC1F 2 and of buffer gases (He and Ar), the energy density and the gas speed, the process is now much less nonlinear than in previous experiments with a single wavelength. Differences to the TEA laser induced process were observed, and generally the pressure influence on yield and selectivity showed a variety of phenomena. They were interpreted in terms of collisional changes of spectra during the laser pulse.

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Section: Rotational Relaxation In Excited Statessupporting

confidence: 75%

“…Instead, as in [12] we used the reduced yield Y13 defined by (5). P, was not directly accessible for us, since we used focussed geometry.…”

Section: Dependences On Energy Densitymentioning

confidence: 99%

Isotope selective dissociation of CHClF2 by a one- and two-wavelengthQ-switched CO2 laser

Fuß

Göthel

Ivanenko

et al. 1992

Z Phys D - Atoms, Molecules and Clusters

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“…The shorter wavelength ~t effectively excites tow lying vibrational states and the longer 22 is better in a region of anharmonically shifted higher levels. From the data of [27], we derive a=l.2×10-2°cm 2 and 2.9×10-21cm z for 9R8 and 9P34, respectively. From the data of [27], we derive a=l.2×10-2°cm 2 and 2.9×10-21cm z for 9R8 and 9P34, respectively.…”

Section: Absorption Measurements With Two-wavelength Irradiationmentioning

confidence: 96%

“…It should be noted, however, that under different conditions (low temperature and pressure, TEA laser with delayed pulses) an increase of tr (9P34) has been observed after pumping at 9R8 [27]. Probably this mechanism does apply for the rare isotope.…”

Section: Absorption Measurements With Two-wavelength Irradiationmentioning

confidence: 96%

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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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