Abstract: A method of isotope-selectively exciting gaseous or vaporous uranium hexafluoride molecules by subjecting them to the action of a monochromatic iodine laser beam, the frequency of which can be adjusted and tuned to an absorption band of the molecules to be excited, the laser beam being scattered by liquid and/or solid nitrogen to obtain a triple Raman-scattering. In a preferred embodiment, the laser has an emission frequency of 7600 to 7610 cm.sup.-1 and the tuning is effected by means of a magnetic field.An apparatus suitable for carrying out such a method comprises a high-performance iodine laser and an optical resonator into which the emission beam or pulses of the laser are focused, one or more Dewar vessels filled with liquid or solid nitrogen being located within the optical resonator. In a preferred embodiment, the laser beam tube is located between the poles of an electromagnet.

Abstract: A system of wholly passive or static elements for increasing laser pulse rate by interleaving the pulses of a plurality of beams of pulsed laser radiation. The system of static elements includes an array of beam splitters which are operative to receive a plurality of beams of pulsed laser radiation and provide a plurality of output beams, each sharing the radiation in each of the input beams. The invention includes a methodology for expanding the array of beam splitter elements to combine any number of input beams, of whatever differing characteristics, to provide a corresponding number of output beams, each sharing a portion of the radiation in each of the input beams.

Abstract: Method and apparatus for sputtering particles of plural isotope types to produce a particle flow of the plural isotope types into a region where laser radiation is generated to produce isotopically selective ionization of at least one isotope type in the sputtered particle flow. Separate collection of the ionized particles is accomplished through application of a magnetic field in the region of ionization and beyond.

Abstract: Organic samples from a liquid chromatograph are deposited on a conveyor belt which transports them into a vacuum chamber at the entry end of a mass spectrometer. The samples are ionized directly on the belt by particle bombardment or by means of a laser beam. Ionization is enhanced by applying an oxide layer to the belt, by neutralizing the image force, and by vaporizing alkali atoms on the belt to reduce the ionization potential.

Abstract: Method and apparatus for separating isotopes in an isotopic mixture of atoms or molecules by increasing the mass differential among isotopic species. The mixture containing a particular isotope is selectively irradiated so as to selectively excite the isotope. This preferentially excited species is then reacted rapidly with an additional preselected radiation, an electron or another chemical species so as to form a product containing the specific isotope, but having a mass different than the original species initially containing the particular isotope. The product and the remaining balance of the mixture is then caused to flow through a device which separates the product from the mixture based upon the increased mass differential.

Abstract: Charged-particle spectroscopy apparatus for the chemical analysis of a sample in which an apertured plate receives charged particles emitted from the sample and transmits them to an analyzer for analyzing the energies of the particles, the aperture of the plate being such as to restrict the particles passing therethrough to a pencil beam of particles from a selected area of the sample.

Abstract: A system for providing multiple traversal illumination of a region with a beam of radiation wherein the illumination provides substantial but not complete overlap at each repeated pass of the beam throughout the region. Because there is a slight shift in direction of the beam on each traversal of the region, it is possible to apply the beam and extract it after a predetermined number of traversals, and means are provided for this purpose. In addition, more than one beam may be applied to the same region, each having a different, predetermined number of traversals before extraction. In this manner, a form of beam combination is achieved.

Abstract: A system for correcting misalignment and divergence in a long, propagating beam of radiation as is typically applied through a plurality of chambers to produce isotopically selective photoexcitation in a system for isotope separation. The corrective apparatus comprises a reflective relay system placed at predetermined intervals along the path of propagation of the radiation where correction of alignment and/or divergence are required. The reflective relay includes a concave mirror employed to correct divergence and which receives radiation directed at it by a first plane reflective surface which in turn responds to the radiation on the path of propagation. The concave mirror reflects toward a second plane mirror which in turn reflects the radiation back onto the path of beam propagation with correction of alignment and divergence.

Abstract: A method and apparatus for analyzing a sample comprising the steps of irradiating a selected area of the sample with a first burst of laser energy to vaporize the sample, condensing the vaporized sample on the surface of an intermediate carrier and analyzing the condensed sample material deposited on the intermediate carrier.

Abstract: A method is provided for separating isotopes of an element where the isots are present in the form of molecules and where the isotopes participate in the vibrations of the molecules and are excited by means of radiation and then separated. Isotopes or elements with a defined nucleon-number are selected in which a shift of the band edges in their absorption spectra is present due to the isotopy effect, and radiation that is used lies within that frequency interval in which the absorption coefficient of one isotope of an isotope mixture or several isotopes of an isotope mixture is greater than that of the other isotope or the remaining portion of the isotopes, respectively.

Abstract: An apparatus for analyzing a sample by electromagnetic irradiation includes a vacuum chamber, a support for holding the sample in the vacuum chamber, an arrangement for irradiating the sample with an electromagnetic beam, a mass analyzer disposed in the vacuum chamber, an arrangement for extracting particles from the sample and introducing them into the mass analyzer and a layer of conductive material situated in the vicinity of support in the zone of the sample.

Abstract: In a method of excitation and selective dissociation by absorption of the monochromatic light emitted by a high-power laser, the laser light is sent at a frequency .nu..sub.1 into an isotopic mixture of gaseous molecules in which a certain number of molecules exhibit transitions between two vibrational levels corresponding to a predetermined isotope and separated by an energy interval .DELTA.E.sub.1 =2h.nu..sub.1. The molecules of a predetermined isotopic species are thus excited preferentially until subsequent dissociation into a number of constituents.

Abstract: Apparatus to reduce pyrophoricity in deposits collected upon collection plates within a chamber employed for vapor deposition. The apparatus is preferably employed in a chamber utilized for isotopically selective photoexcitation, ionization and separation of metallic uranium vapor. The uranium vapor which collects on all surfaces exposed to it within the chamber is caused to collect in a relatively dense, non-porous body by maintaining a suitably elevated temperature for those surfaces while at the same time keeping the chamber itself cooled. The elevated temperature is achieved by baffles shielding the collection plates from the cooler chamber walls to reduce thermal radiation thereto and/or by applying additional thermal energy to the plates.

Abstract: A tandem ion accelerator is disclosed having a charge reversing device for recharging negative ions into positive ions. The recharging is carried out in a matter-free zone and a light source is provided having a high luminous density for recharging the negative ions into positive ions. Preferably a deflecting device is provided for displacing an ion path and the light source is arranged such that a path of the light emitted from the light source coincides at least with a portion of the ion path.

Abstract: In a method for producing selected mass spectra by directing electromagnetic radiation through an optical system onto sample material for vaporization, destruction, excitation and/ or ionization in the microrange, setting the expanse of the irradiation region of the sample by selection of the energy density of the radiation, and detecting the released particles, the radiation power density is varied for producing mass spectra having respectively different proportions of atom and molecule spectra.

Abstract: Apparatus for directing a beam of electromagnetic radiation onto a sample by focusing and deflecting the radiation, employing a spherical mirror for focusing and deflecting the radiation onto the sample.

Abstract: Method and apparatus for selectively exciting and separating a selected isotope or molecule from a mixture of isotopes or molecules, particularly useful in separation of isotopes of uranium and other heavy metals. The method serially includes placing the mixture of isotopes in an excited gaseous state, selectively de-exciting one or more isotopes of the mixture, and subsequently permanently separating the de-excited and excited isotopes.

Abstract: A sample analyzer includes a microscope for alternatively focusing an electromagnetic radiation on the sample to cause ion emission therefrom and visually observing the sample; a mass spectrometer for the mass analysis of the emitted ions; an illuminating device for lighting the sample for the microscopic visual observation thereof; an ion optical system for directing the emitted ions into the mass spectrometer; and a displaceably supported carrier carrying the ion optical system and at least one part of the illuminating device. The carrier has a first position in which the ion optical system is in an operating position in alignment with the sample and a second position in which the illuminating device is in an operating position in alignment with the sample. There is further provided an actuator for selectively moving the carrier into its positions in a direction generally perpendicular to the axis of the ion optical system.

Abstract: This invention relates to an apparatus in which laser pulses of up to about one nanosecond duration (.about.10.sup.-9 secs) and high intensity, more than 10.sup.11 watts cm.sup.-2, generate energetic (>>10 keV) ions, which can have very high charge states of more than twenty times the charge state of a single electron, from solid or liquid targets using non-liner, electrodynamic forces operating within the target material. In the present invention the energetic, highly charged ions are produced in such a manner that isotopes of a particular element forming the target can be separated into their respective groups travelling at particular velocities and directions, at distances of more than one meter from the irradiated target. In the present invention, the energetic, highly charged ions are generated and accelerated with high efficiency (>25%) within a relatively cold plasma (<1000 eV) generated from the target material.

Abstract: A beam of ammonia molecules including the isotopes N.sup.15 H.sub.3 and N.sup.14 H.sub.3 is generated wherein some of the molecules of each isotope reside in an asymmetric energy state and other of the molecules of each isotope reside in a symmetric energy state. The symmetric state molecules are removed from the beam in a first state selector to provide a beam containing substantially only asymmetric state molecules of each isotope. The latter beam is fed to a resonant microwave cavity where it interacts with microwaves of a frequency inducing asymmetric state to symmetric state transitions for molecules of one of the isotopes but not for molecules of the other isotope. Either the asymmetric state molecules or the symmetric state molecules are removed from the resultant beam in a second state selector to provide a beam containing substantially only molecules of the other energy state enriched in the isotope N.sup.15 H.sub.3.

Abstract: Reaction of laser radiation and a reactive medium is conducted by reflecting a hollow conical beam of the radiation back and forth between two aspheric mirrors. This gives a long path length for the radiation passing through the medium, although the length of the reaction zone, i.e. the distance between the mirrors, may be comparatively small. By selection of the curvature of the mirrors, the radiation flux density can be controlled so that it is substantially uniform or so that it exhibits a pre-determined cylindrically symmetrical variation across the width of the reaction chamber, and this distribution of the flux density can be matched to the distribution of availability of reactive species within the reaction zone.

Abstract: A method of irradiating a collection of particles by ultrashort pulses of light with isotopic selectivity having application in various methods of isotope separation (two step photoionization, photochemical separation or radiation pressure). In particular there is disclosed a method and apparatus for the efficient acceleration and collection of particles by means of radiation pressure, exemplified by separating a preselected isotope species from a gaseous mixture of isotopes. The gaseous mixture is irradiated with ultrashort, repetitious pulses of coherent light, each pulse having an intensity, frequency and duration selected to create momentum changes in the preselected gaseous isotope whereby to spatially isolate the isotope. Preferably, irradiation is carried out in the cavity of a mode-locked laser into which the gaseous mixture is injected.

Abstract: A method for separating isotopes in which a selected isotope of a given molecule is first excited to enhance preferential dissociative electron attachment, which facilitates the separation of the desired isotope from its natural mixture. Molecules incorporating the particular isotope of interest are selectively excited to the proper vibrational and/or electronic state by narrow line radiation to enhance preferential dissociative electron attachment. The excited molecules are then exposed to low energy electrons which dissociatively attach to the excited molecules forming stable negative ion fragments. The negative ion or neutral fragments containing the desired isotopes are then separated from the remaining mixture resulting in an enrichment of the desired isotope.

Abstract: An arrangement for detecting low concentrations of molecular gases. A gaseous sample containing molecules of the gas to be detected is simultaneously subjected to two photon beams which, for example, may be generated by lasers. The wave length of the first photon beam corresponds to the energy separation between the ground electronic state and an excited electronic state of the molecular gas and the second photon beam contains energy in a wave length corresponding to the energy separation between the excited electronic state and the ionization limit of the molecule. Detection of the amount of ionization achieved is a measure of the concentration of the molecular gas in the sample. Simultaneous identification of the particular wave lengths causing the transition of the molecules from the ground energy state to the excited state provides an additional parameter identifying the molecules.

Abstract: A method for deriving, from a starting material including an element having a plurality of isotopes, derived material enriched in one isotope of the element. The starting material is deposited on a substrate at less than a critical submonatomic surface density, typically less than 10.sup.16 atoms per square centimeter. The deposit is then selectively irradiated by a laser (maser or electronic oscillator) beam with monochromatic coherent radiation resonant with the one isotope causing the material including the one isotope to escape from the substrate. The escaping enriched material is then collected. Where the element has two isotopes, one of which is to be collected, the deposit may be irradiated with radiation resonant with the other isotope and the residual material enriched in the one isotope may be evaporated from the substrate and collected.

Abstract: Atoms of hydrogen or deuterium are fully ionized by a three-photon process which is enhanced by the two-photon 1S.fwdarw.2S resonant transition. The resultant ions are detected with high efficiency to provide discrimination between small concentrations of atomic hydrogen and atomic deuterium in a vacuum or in the presence of a background gas. The use of two unequal photo energies to pump the two-photon resonance provides the capability of mapping the individual three dimensional distribution of the hydrogen or deuterium. The detection process is also appropriate to determining these data in dishcarge plasmas and flames.

Abstract: A system for applying accelerating forces to ionized particles of a vapor in a manner to suppress the flow of electron current from the vapor source. The accelerating forces are applied as an electric field in a configuration orthogonal to a magnetic field. The electric field is applied between one or more anodes in the plasma and one or more cathodes operated as electron emitting surfaces. The circuit for applying the electric field floats the cathodes with respect to the vapor source, thereby removing the vapor source from the circuit of electron flow through the plasma and suppressing the flow of electrons from the vapor source. The potential of other conducting structures contacting the plasma is controlled at or permitted to seek a level which further suppresses the flow of electron currents from the vapor source.

Abstract: A system for determining the stable energy levels of a species ion, of an atomic, molecular, or radical type, by application of ionizing energy of a predetermined level, such as through photoionization. The system adds a trapping gas to the gaseous species to provide a technique for detection of the energy levels. The electrons emitted from ionized species are captured by the trapping gas, only if the electrons have substantially zero kinetic energy. If the electrons have nearly zero energy, they are absorbed by the trapping gas to produce negative ions of the trapping gas that can be detected by a mass spectrometer. The applied energies (i.e. light frequencies) at which large quantities of trapping gas ions are detected, are the stable energy levels of the positive ion of the species. SF.sub.6 and CFCl.sub.3 have the narrowest acceptance bands, so that when they are used as the trapping gas, they bind electrons (to form negative ions) only when the electrons have very close to zero kinetic energy.

Abstract: A system for producing isotopically selective excitation of particles of a predetermined isotope type in a mixture of isotopes from plural low-lying energy levels to respective, plural excited energy levels. Ionization and separate collection of particles of the predetermined isotope type are then achieved through further excitations through a single, further excited energy state. Decay losses from the second excited energy states are reduced due to distribution of the excited particles among several states and resulting lower cross-sections for self-lasing decay.

Abstract: Isotopes are separated from a gas mixture by accelerating the gas mixture containing the isotopes to ultrasonic speeds sufficient to bring the gas temperature to 150.degree. K or less. Simultaneously, the gas is subject to a pressure well above the vapor pressure of the gas at said temperature. Under these conditions the gas is subjected to a laser radiation having a wave length corresponding to the absorption line or band of the molecules containing the isotopes to be separated, whereby the molecules are excited so that they may be separated by conventional devices. The present apparatus has a high pressure reservoir supplying the gas mixture through a device for producing said ultrasonic speeds into an expansion chamber. As the gas flowing at said speeds is irradiated by the laser beam, it expands into a low pressure reservoir. The laser is arranged so that the laser beam extends across the expanding gas flow at a point where the expanding gas does not yet start to condense.

Abstract: An apparatus for ionizing and vaporizing non-volatile or thermally labile molecules of a sample for introduction into a mass spectrometer analyzer which comprises a housing containing an ionization chamber; an ion exit port for the introduction of gaseous ions from said ionization chamber into a mass spectrometer analyzer on the portion of the housing attached to said mass spectrometer analyzer; inlet means for introducing a gaseous reactant into said ionization chamber within said housing; inlet means for admitting high energy radiation into said ionization chamber within said housing to at least partially ionize the molecules of said gaseous reactant; aperture means open into said ionization chamber of said housing for admitting a conductive emitter characterized by having a conductive element of a highly irregular surface upon which is deposited said sample for analysis into said mass spectrometer analyzer; and a vacuum exit aperture in said housing by which the pressure within said ionization chamber can

Abstract: Method and apparatus for achieving isotopically selective adiabatic inversion, particularly for improved isotope separation efficiency. In a preferred embodiment for practicing the invention, chirped laser radiation induces photoionization of a vapor state material in isotopically selective excitation and ionization energy steps. A frequency sweep or "chirp" is provided in the excitation laser radiation at a controlled rate and over a range of frequencies which is limited to prevent loss of selectivity in the excitation. The frequency swept radiation has a theoretical capability of producing 100% inversion of ground state particles in the vapor. The features of the invention additionally permit excitation of a material to very high energy states useful in producing high frequency, ultraviolet lasing.

Abstract: The invention concerns a device for separating isotopes. A gas containing the isotopes to be separated is excited by a radiation having an intermediate frequency between the central frequencies of the two absorption lines of the two isotopes, those two lines coinciding partly by Doppler enlarging, so as to make it possible to separate subsequently the excited molecules according to the direction of their motion. Application to isotopic enriching.

Abstract: The element "lithium" has strong absorption lines near 6707.84 A and 3232.61 A and possesses specific isotope shifts at the respective absorption lines. With the aid of a laser capable of controlling the oscillation spectral width accurately to 0.01 A, the isotopes of this element are separated from each other by irradiating lithium atomic beam with a laser beam tuned to the absorption line of either of the isotopes, .sup.6 Li and .sup.7 Li, for thereby selectively exciting the isotope, ionizing the excited isotope along by irradiation with a laser beam having one photon energy enough to pump it from the excited state to the ionized state and separating the ionized isotope from the un-ionized isotope by means of a mass-filter.

Abstract: 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.

Abstract: In a method of excitation and selective dissociation by absorption of the monochromatic light emitted by a high-power laser, the laser light is sent at a frequency .nu..sub.1 into an isotopic mixture of gaseous molecules in which a certain number of molecules exhibit transitions between two vibrational levels corresponding to a predetermined isotope and separated by an energy interval .DELTA.E.sub.1 = 2h.nu..sub.1. The molecules of a predetermined isotopic species are thus excited preferentially until subsequent dissociation into a number of constituents.

Abstract: Gases or gas mixtures are analyzed by a device and process involving laser-induced vibrational excitation of the gases or mixtures, followed by mass spectrometry. A sample of the gas is subjected to radiation, preferably infrared radiation, from a tunable laser, so as to casue vibrational-excitation of the sample by absorption of the radiation. The sample so treated is then subjected to mass spectrometry, which detects changes in the vibrational-excitation of the sample. Detection of such changes indicates infrared absorption by the sample at the wavelength at which the tunable laser is set. The wavelength of infrared absorption so determined is a characterizing property of the sample.

Abstract: A gaseous jet of a mixture of matter or isotopes to be separated is penetrated by a polarized electromagnetic wave, e.g., a laser or maser beam. The required frequency is in the vicinity of a resonant frequency of a molecular dipole of the substance to be separated. For deflecting the mixture components and therefore, their separation, the forces on the molecular dipoles produced by the electric and/or the magnetic field are utilized. SUBACKGROUND OF THE INVENTIONThe present invention concerns a method for separating gaseous mixtures of matter or isotopes. The problem of separating mixtures of matter into their individual components occurs frequently in technology. Among this class of problems are, for instance, also the concentration and depletion of individual substances in mixtures of substances, such as, in nuclear technology, the enrichment of fissionable uranium 235, of which only 0.7% is present in the natural isotope mixture of uranium. The methods heretofore applied for this purpose, e.g.

Abstract: A system for correcting misalignment and divergence in a long, propagating beam of radiation as is typically applied through a plurality of chambers to produce isotopically selective photoexcitation in a system for isotope separation. The corrective apparatus comprises a reflective relay system placed at predetermined intervals along the path of propagation of the radiation where correction of alignment and/or divergence are required. The reflective relay includes a concave mirror employed to correct divergence and which receives radiation directed at it by a first plane reflective surface which in turn responds to the radiation on the path of propagation. The concave mirror reflects toward a second plane mirror which in turn reflects the radiation back onto the path of beam propagation with correction of alignment and divergence.

Abstract: Method and apparatus for impact ionization of particles excited with isotopic selectivity, particularly for use in a system of uranium isotope separation and enrichment. Efficient impact ionization is achieved by first selectively exciting vaporized particles of the desired isotope in a beam of finely tuned laser radiant energy. The energies of the interacting photons are selected to produce a total energy shift during excitation which is slightly less than the ionization energy for the selected isotope. The excited isotope will thus be raised to an excitation level only slightly below the ionization level. This level is selected to permit efficient ionization, particle collisional ionization, between energetic particles in the uranium vapor environment and the highly excited particles of the desired isotope type.

Abstract: A method of separating one isotopic species of a given element from a mixture. Collisionless plasma instabilities slow down the ions and oppositely charged electrodes separate the isotopes.

Abstract: In an isotope-separation process, using polyatomic molecules having a complicated absorption spectrum such that the isotope shifts are masked, a plurality of laser pulses are used to irradiate a gaseous mixture of molecules including a compound of a desired isotope so as to raise the molecules thereof to higher vibrational energy levels which are substantially unpopulated thermally. The laser pulses have slightly different wavelengths corresponding to respective specific rotational lines of specific vibrational level transitions of molecules containing the desired isotope.

Abstract: A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated.

Abstract: A method for separating isotopes in which a selected isotope is first ionized in a partially bounded region and then driven toward the boundary by space charge electric fields. Radial electric fields, which accelerate movement of the charged particles towards the walls of the boundary, are generated by charge separation associated with ambipolar diffusion of the particles in the plasma column. Selective photoexcitation leads to the preferential ionization of the isotopic component to be separated from the gas mixture. The resulting altered gas mixture component concentrations in the central region and periphery of the bounded area flow from the system through different output channels.

Abstract: A method of making a pattern for a photolithographic mask. A field ion source is advantageously utilized to produce heavy ions with a high beam current density. The ions are accelerated and directly bombard a metallic coating on the mask substrate to form openings therein in the desired pattern.

Abstract: Apparatus for the separation and extraction of molecular isotopes. Molecules of one and the same isotope are preferentially photo-dissociated by a laser and an ultra-violet source, or by multi-photon absorption of laser radiation. The resultant ions are confined with a magnetic field, moved in opposite directions by an electric field, extracted from the photo-dissociation region by means of screening and accelerating grids, and collected in ducts.

Abstract: Isotope separation method and means are shown wherein an atomic beam containing two or more isotopes is exposed to radiation at a predetermined first wavelength to excite atoms of only one said isotope to a first intermediate excited state without substantially exciting atoms of other isotopes. These excited atoms are excited by a second radiation source at a second predetermined wavelength to a state of high principal quantum number, a Rydberg state, beneath the ionization continuum, again substantially without exciting atoms of said other isotopes to such high energy levels since substantially none of the other isotopes are in the intermediate excited state. From this bound atomic level only slightly below the ionization limit, the highly excited atoms are field ionized by electron tunneling and thence removed from the nonionized atoms by use of a moderate electric field.

Abstract: An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

Abstract: A process for separating gaseous isotope mixtures having the general molecular composition X.sub.n1.sup.(1) X.sub.n2.sup.(2). . . X.sub.ni.sup.(i), where a constituent X.sup.(k) can be replaced by an isotope X.sup.-(k) by irradiation with laser light.

Abstract: Isotopic separation is accomplished by (1) a second photon irradiation step for selective ionization of a first isotopic species and (2) selective precipitation of a generally immiscible liquid from the saturating vapor phase on the ionized species. The first photon corresponds with a sharply defined spectral portion of the irradiation which exclusively excites the first species to a vibrational level. The second photon further excites this species to its ionization level. Selective precipitation is by coulombic attraction between the ionized species and the vapor. The procedure is applicable to any vapor phase ionizable material.