Abstract: The method for concentrating an oxygen isotope or isotopes of the present invention combines the step of concentrating 17O and/or the step of depleting 18O that utilizes photodissociation of ozone by a laser beam with an oxygen distillation step that concentrates the oxygen isotope. At this time, it is preferable to carry out a step of isotope scrambling in addition to the above. When both a step of concentrating 17O and a step of depleting 18O are carried out, whichever thereof may be done first prior to the other. Also these steps may be placed either before or after the oxygen distillation step. Moreover, at least one of said oxygen distillation step, the concentrating 17O step, the depleting 18O step and the isotope scrambling step is preferably carried out twice or more.

Abstract: The method for concentrating an oxygen isotope or isotopes of the present invention combines the step of concentrating 17O and/or the step of depleting 18O that utilizes photodissociation of ozone by a laser beam with an oxygen distillation step that concentrates the oxygen isotope. At this time, it is preferable to carry out a step of isotope scrambling in addition to the above. When both a step of concentrating 17O and a step of depleting 18O are carried out, whichever thereof may be done first prior to the other. Also these steps may be placed either before or after the oxygen distillation step. Moreover, at least one of said oxygen distillation step, the concentrating 17O step, the depleting 18O step and the isotope scrambling step is preferably carried out twice or more.

Abstract: A method for laser-assisted separation and enrichment of silicon isotopes such as 28Si, 29Si and 30Si on the basis of infrared multiple-photon dissociation of silicon halides represented by Si2F6, wherein the silicon halides are irradiated synchronously with multiple infrared pulsed laser beams at different wavelengths.

Abstract: A method for laser-assisted separation and enrichment of silicon isotopes such as 28Si, 29Si and 30Si on the basis of infrared multiple-photon dissociation of silicon halides represented by Si2F6, wherein the silicon halides are irradiated synchronously with multiple infrared pulsed laser beams at different wavelengths.

Abstract: The present invention relates to a method for enrichment of oxygen 18, which comprises the steps of optionally adding a hydrocarbon to a saturated aliphatic ether other than dimethyl ether and/or a saturated cyclic ether as an oxygen 18-containing starting material, irradiating the material(s) with laser light to induce oxygen 18 selective photodecomposition and separating oxygen 18-containing products from the photodecomposed products. Oxygen 18 enriched compounds obtained by the present invention can be used as tracers and the like.

Abstract: This invention relates to a process for enriching carbon 13 by mixing a halogenomethane containing one or more fluorine atoms and carbon 13 of natural isotopic abundance with one or two or more additive gases selected from a group of oxygen-containing oxidizing agents, halogens, and hydrogen halides, irradiating the resulting raw material gas mixture by a carbon dioxide laser to cause selective dissociation and reaction of the halogenomethane of carbon 13, separating the unchanged substances from the reaction mixture to obtain a product enriched with carbon 13, further converting the enriched product to carbon monoxide, and enriching carbon 13 by low-temperature distillation of the carbon monoxide. The process has advantages of low overall energy consumption, high yields of carbon 13, easy separability of the unchanged substances and high degrees of carbon 13 enrichment.

Abstract: An enrichment method of carbon 13 by use of the multistage laser irradiation. A mixture of CHClF.sub.2 and Br.sub.2 is used as a start substance. The mixture is irradiated with laser rays emitted from a carbon dioxide gas laser to obtain CBr.sub.2 F.sub.2 enriched with carbon 13. This CBr.sub.2 F.sub.2 enriched with carbon 13 is once more irradiated with laser rays emitted from a carbon dioxide gas laser to produce C.sub.2 Br.sub.2 F.sub.4 which is further enriched with carbon 13. Alternatively, the product CBr.sub.2 F.sub.2 of the first laser irradiation is once more irradiated together with O.sub.2 to produce COF.sub.2 which is further enriched with carbon 13.

Abstract: Silicon isotopes are effectively separated by irradiating a polysilane compound or a fluoromosilane compound according to this invention with infrared laser rays. The polysilane compound is defined by the formula.Si.sub.a X.sub.b H.sub.cwhere 2.ltoreq.a.ltoreq.3, 0.ltoreq.b.ltoreq.2a+2, 2a+2=b+c and X represents a kind or kinds of halogen, and the fluoromonosilane compound is defined by the formula.SiFX.sub.1 X.sub.2 X.sub.3where X.sub.1 and X.sub.2 are selected from the group consisting of H, Cl, Br, I, F, an alkyl radical and a halogen derivative of the alkyl radical, and X.sub.3 is selected from the group consisting of H, Cl, Br, I, an alkyl radical and a halogen derivative of the alkyl radical.