Government of the United States of America, As Represented by the Secretary of Commerce

Richard A Keller

Robert B Green

Gabriel G Luther

John C Travis

Joseph J Ritter

Michel Lamotte

Peter C Schenk

Harry J Dewey

Peter C Schenck

An apparatus and method for utilizing the opto-galvanic effect to perform ectroscopic or analytic investigations of atomic or molecular species. A sample of the substance to be analyzed is vaporized in an analytical flame, gas discharge tube, high temperature furnace or the like, and the vapor is irradiated with chopped or pulsed variable wavelength monochromatic light. The electrical resistance of the vapor is monitored as the frequency of the radiation is tuned through one or more electronic transition frequencies of the substance. The resistance spectrum resembles the optical absorption spectrum of the species in the vapor. The optogalvanic effect may also be used to frequency lock a laser to a transition frequency of a substance in a gas discharge cell.

Frequency stabilized laser

An apparatus and method for utilizing the opto-galvanic effect to perform spectroscopic or analytic investigations of atomic or molecular species. A sample of the substance to be analyzed is vaporized in an analytical flame, gas discharge tube, high temperature furnace or the like, and the vapor is irradiated with chopped or pulsed variable wavelength monochromatic light. The electrical resistance of the vapor is monitored as the frequency of the radiation is tuned through one or more electronic transition frequencies of the substance. The resistance spectrum resembles the optical absorption spectrum of the species in the vapor. The opto-galvanic effect may also be used to frequency lock a laser to a transition frequency of a substance in a gas discharge cell.

Apparatus for galvanic detection of optical absorptions

An isotopic starting material consisting of a mixture of chlorine-35 and chlorine-37 isotopic species of an isotopic compound having the formula CYClX, wherein Y is O or S and X is Cl or F, such as thiophosgene, is selectively isotopically enriched by means of a laser-induced photochemical reaction between selected chlorine isotopic species in the starting material and a dialkoxyethylene, such as diethoxyethylene. The method is carried out by irradiating with laser radiation, a gaseous mixture at a reduced pressure of the isotopic starting material and the dialkoxyethylene, until a stable reaction product is formed. The wavelength of the radiation is selected so as to selectively excite at least one but less than all of the chlorine isotopic species in the starting material, thereby causing the excited species to preferentially react with the dialkoxyethylene. The resulting reaction product is readily separable from the reaction mixture thereby leaving unreacted isotopic starting material selectively enriched in the unexcited chlorine isotopic species.

Photochemical method for chlorine isotopic enrichment

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White Rock, NM, United States of America

Richard A Keller