Showing papers on "Argon published in 1980"
TL;DR: In this article, a small concentration of suitably chosen noble gas to a reactive plasma is shown to permit the determination of the functional dependence of reactive particle density on plasma parameters, and examples illustrating the simplicity of this method are presented using F atomic emission from plasma-etching discharges and a comparison is made to available data in the literature.
Abstract: The addition of a small concentration of suitably chosen noble gas to a reactive plasma is shown to permit the determination of the functional dependence of reactive particle density on plasma parameters. Examples illustrating the simplicity of this method are presented using F atomic emission from plasma‐etching discharges and a comparison is made to available data in the literature.
796 citations
TL;DR: In this article, a model of the evolution and isotopic composition of ambient argon retained within the metamorphic host rocks during cooling was presented, based on a step-heating argon analysis of both neutron irradiated and unirradiated samples.
313 citations
TL;DR: In this paper, it was shown that the ion peening transition may be controlled by the transfer of momentum to the depositing film, which is consistent with results obtained in low-pressure, cylindrical post-magnetron sputtering.
Abstract: Bombardment of thermally evaporated chromium films with energetic inert gas ions during deposition (ion peening) causes marked changes in properties when the dose exceeds a minimum critical value. The property changes are characterized by a sharp reversal of intrinsic stress from high‐tensile to high‐compressive values, increases in the optical reflectance and optical density to levels approaching pure bulk chromium, and enhanced resistance to oxidation on heating. Observations of the shift in critical ion dose with accelerating voltage and ionic mass (argon and xenon) indicate that the ion peening transition may be controlled by the transfer of momentum to the depositing film. This observation is found to be consistent with results obtained in low‐pressure, cylindrical post‐magnetron sputtering, which ion peening was devised to simulate.
149 citations
TL;DR: In this paper, it was shown that the environment of the central channel of an argon ICP is not in a state of local thermal equilibrium, as predicted from Griem's criterion.
125 citations
TL;DR: In this article, a high pressure, radio frequency discharge nozzle beam source has been developed for the production of very intense (⩾1018 atoms sr−1 s−1) supersonic beams of oxygen atoms.
Abstract: A high pressure, radio frequency discharge nozzle beam source has been developed for the production of very intense (⩾1018 atoms sr−1 s−1) supersonic beams of oxygen atoms. An efficient impedance matching scheme has been devised for coupling the radio frequency power to oxygen–rare gas mixtures as a function of gas pressure, temperature, and composition. Techniques for localizing the discharge directly behind the orifice of a specially designed quartz nozzle have also been developed. The above combine to yield a beam source which reliably produces a high degree of molecular dissociation in oxygen–rare gas mixtures at pressures up to 350 Torr. Atomic oxygen mean translational energies from 0.14–0.50 eV have been achieved using the seeded beams technique with Mach numbers up to 10 being realized. When helium is used as the carrier gas both O(3PJ) and O(1D2) atoms are present in the beam, while only ground state atoms appear to be present in argon seeded mixtures. This paper describes the design, constructi...
114 citations
TL;DR: In this article, a single metal (Mo) sputtered in a variety of gases (Ne, Ar, Kr, Xe) was found to have high compressive stress, maximum reflectance, minimum resistivity, entrapped inert gas, and dense Zone-T microstructure.
Abstract: Previous work by the present authors on metal films sputtered from cylindrical‐post magnetron sources has established the existence of an abrupt transition in internal stress and other properties that occurs as the working pressure is lowered. High compressive stress, maximum reflectance, minimum resistivity, entrapped inert gas, and dense, Zone‐T microstructure were found in a wide variety of pure metals and alloys when sputtered in argon at sufficiently low pressures. The present study reports this same phenomenon for a single metal (Mo) sputtered in a variety of gases (Ne, Ar, Kr, Xe). In this case the transition pressure varies inversely with the mass of the sputtering gas, from less than 0.3 Pa for xenon to over 0.9 Pa for neon. The concentration of inert gas in the films also varies inversely with the mass, increasing by two orders of magnitude from krypton to neon. Deposition through a narrow slit‐aperature established that the entrapped gas comes from the sputtering cathode (backscattered, neutral...
111 citations
TL;DR: In this paper, the rf diode sputtering of a ZnO target using an Ar/O2 gas mixture was studied as a function of the O2 content of the sputtering gas.
Abstract: The rf diode sputtering of a ZnO target using an Ar/O2 gas mixture was studied as a function of the O2 content of the sputtering gas. Films sputtered using gas mixtures containing 0–100% O2 were investigated. Glow discharge spectrometry was used to monitor the ionized species present in the various Ar/O2 plasmas. The crystallographic orientation of the films was found to be highly correlated with the ratio of the number of Zn to ZnO ions in the plasma. The most highly ordered films were obtained when the Zn to ZnO ion ratio was at a minimum which occurred when a 75% Ar/25% O2 gas mixture was used. This result can be explained in terms of the relative degree of oxidation of the ZnO target surface and the number of secondary electrons in the plasma for the various Ar/O2 sputtering gas mixtures.
93 citations
TL;DR: In this article, spherical silver microcrystallites with mean diameters between 10 and 200 A have been prepared by gas aggregation techniques using argon gas in a dynamic flow system, and a small quantity of these crystallites were allowed to condense onto an umorphous carbon foil, which allowed a direct characterisation of the size distribution by evaluating the corresponding electron micrographs.
93 citations
TL;DR: In this article, the infrared spectra of the water formaldehyde complex in argon and nitrogen matrices were obtained and it was shown that water forms a hydrogen bond with formaldehyde.
Abstract: Infrared spectra of the water formaldehyde complex in argon and nitrogen matrices have been obtained. The complex shifts of the water fundamentals clearly show that water forms a hydrogen bond with formaldehyde. HDO prefers to form a D bond, but a metastable H‐bonded complex is observed in nitrogen matrices below 20 K.
90 citations
IBM1
TL;DR: In this article, the authors investigated bombardment-induced oxidation of silicon at room temperature in an AES-SIMS system and found that the oxygen-induced enhancement of the Si+ intensity is directly related (most likely proportional) to the concentration of SiO2.
88 citations
TL;DR: In this paper, the emission spectrum of I2 in Ar is examined as a function of pressure and temperature, and evidence is found for at least twelve of the ion-pair states, of which D'(Zg) is the lowest.
TL;DR: In this paper, the authors measured detailed line profiles using a high-resolution tunable laser difference-frequency spectrometer in order to test various collisional lineshape models, and the measured lineshapes and the pressure dependence of the widths are least-squares fit in the limits of strong and weak velocity-changing collisions.
TL;DR: In this article, the decay rate of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon-argon mixtures over the pressure range 102 to 104 Torr.
Abstract: Formation and decay rates of the lowest 0u+ and 1u states of Xe2*, excited by monochromatized synchrotron radiation from the Stanford storage ring (SPEAR), have been measured in pure xenon and in xenon–argon mixtures over the pressure range 102 to 104 Torr. The results are interpreted to yield radiative lifetimes (4.6±0.3 and 99±2 nsec, respectively, for vibrationally relaxed 0u+ and 1u molecules), vibrational relaxation rates [7×10−11 and 6×10−12 cm3/sec for Xe2* (1u) in collisions with xenon and argon, respectively], the Xe2* (0u+) three‐body formation rate from Xe(3P1) (5.3×10−32 cm3/sec), and rates for 0u+–1u mixing by collisions with xenon and argon.
TL;DR: In this article, the effects of some matrix and concomitant elements on the determination of cadmium and arsenic by optical emission spectrometry with an inductively coupled plasma using sample introduction with a graphite rod electrothermal vaporization device have been investigated.
Abstract: The effects of some matrix and concomitant elements on the determination of cadmium and arsenic by optical emission spectrometry with an inductively coupled plasma using sample introduction with a graphite rod electrothermal vaporisation device have been investigated. These effects are shown to be caused by variations in pre-vaporisation loss of analyte and analyte transport efficiency to the plasma. Selenium (VI) is shown to effect matrix stabilisation and to improve sample transport efficiency via experiments utilising radio-active cadmium-115m as a tracer.
TL;DR: In this paper, a high-flux beam source for the production of helium, neon and argon metastable atoms was constructed for a DC electric discharge maintained in an expanding gas.
Abstract: A high-flux beam source has been constructed for the production of helium, neon and argon metastable atoms. The source is a DC electric discharge maintained in an expanding gas. A metastable flux of 3.5*1014, and 7.2*1013 atoms s-1 sr-1 has been achieved with most probable energies of 66, 72 and 74 meV for the helium, neon and argon sources, respectively. Time-of-flight measurements showed the widths of the respective velocity distributions to be 45%, 27% and 27%.
TL;DR: In this article, the initial steps involved in the thermal decomposition of acetylene and diacetylene in the temperature range 1850 to 3000 K have been investigated by monitoring the hydrogen-atom production behind reflected shock waves in highly diluted mixtures of argon (5 −400 ppm, total densities 6 × 10−6 to 2.7 × 10 −5 mol/cm3).
TL;DR: In this paper, thin films of SnO2 were prepared by the radio frequency (13.56 MHz) sputtering technique in a wide range of oxygen/argon concentrations within the sputtering system.
Abstract: Thin films of SnO2 were prepared by the radio frequency (13.56 MHz) sputtering technique in a wide range of oxygen/argon concentrations within the sputtering system. The films were analyzed by means of transmission and scanning electron microscopy, x-ray diffractometry and Auger electron spectroscopy. The results showed the films to be polycrystalline with an average grain size of 400 A. Room temperature resistances of as-sputtered films showed a strong dependence on the oxygen concentration in the sputtering environment. Electrical conductivity studies of these films in oxygen and in hydrogen revealed the fundamental charge transfer mechanisms in the observed gas sensitivity of the material to be due to an interaction of the hydrogen with chemisorbed oxygen ions on the semiconductor surface. Finally, a means of providing selectivity between H2S and H2 responses was studied.
CERN1
TL;DR: In this article, the energy loss of charged particles in a gas has been estimated by a computer simulation technique with a view of studying primary cluster counting as a mean of the particle identification.
TL;DR: In this article, the authors studied the oxidation kinetics during sputtering of an Al target in a planar magnetron and showed that the ratio in sputtering rates of Al and Al2O is a factor of 2 greater than predicted from calculated yield values.
Abstract: The oxidation kinetics during sputtering of an Al target in a planar magnetron have been studied by accurate measurement of the total pressure produced by argon/oxygen mixtures. When a 5×8‐in. target is rf sputtered at 500 W with a fixed argon flow, the pressure is constant at 4.6 mTorr until the oxygen flow rate is increased to 2.1 cm3/min. At this critical flow, the total pressure increases to 7.85 mTorr in 100 min and the time dependence is explained by a parabolic oxidation rate. The equilibrium oxide thickness is about 100 nm and has been measured by determining the time necessary to cause a sudden increase from 180 to 290 V in self‐bias voltage. When the target was oxidized, Al2O3 films were deposited at 3 nm/min, whereas Al was deposited in an argon discharge at 70 nm/min. The ratio in sputtering rates of Al and Al2O is a factor of 2 greater than predicted from calculated yield values. Before target oxidation, oxygen added to the system is gettered by the film until, at values just below the critical value, Auger analysis shows the films have a composition AlOx where 1
TL;DR: In this paper, the electron ionization coefficients for Ar, Kr, and Xe have been measured in the low E/N region using a drift-tube apparatus, yielding a revised set of inelastic cross sections which differ from earlier ones primarily in the inclusion of shape resonances.
Abstract: The electron ionization coefficients for Ar, Kr, and Xe have been measured in the low E/N region [(0.5–4) ×10−16 V cm2] using a drift‐tube apparatus. At low field values, the ionization coefficient was found to be anomalously large, a fact attributed to surface photoelectron emission from radiating metastables. This contribution also explains the discrepancy between earlier measurements and recent calculations based on the transport equation. The measurements were analyzed on the basis of two contributions to the ionization rate and calculations of the transport equation, yielding a revised set of inelastic cross sections which differ from earlier ones primarily in the inclusion of shape resonances.
TL;DR: In this paper, the authors discuss the techniques for the measurement of hydrogen evolution by nodules, including mass spectrometers, gas chromatograph, and amperometry, using a column 65 mm diameter by 2 m length of silica gel at room temperature.
Abstract: Publisher Summary This chapter discusses the techniques for the measurement of hydrogen evolution by nodules The evolution of H2 by nodules has been measured by mass spectrometry, gas chromatography, and amperometry All of these methods, except the amperometric technique, require sampling of the gas mixture over nodules at intervals and subsequent analyses The amperometric technique allows continuous measurement of H2 evolution by samples of nodules or bacteroids isolated from nodules Hoch employed mass spectrometry to measure H2 evolution by nodules The gas mixture above them was sampled and analyzed for masses 2 and 4 In these experiments, helium was used as an internal standard A gas chromatograph equipped with a thermal conductivity detector has been used for the quantitation of H2 evolved from legume nodules In this method, investigators employed a column 65 mm diameter by 2 m length of silica gel at room temperature with N2 as the carrier gas Argon (Ar), whose thermal conductivity is one-tenth that of H2, is the most readily available carrier gas for use in the detection of H2 with a thermal conductivity detector Nitrogen, whose thermal conductivity is one-seventh that of H2, is less expensive than Ar and may be used as a carrier gas with only a slight loss of sensitivity
TL;DR: In this article, nonresonant, low-energy atomic oxygen transitions from high-energy (11 to 16 eV) singlet, triplet, and quintet states are observed in the 2 kW argon inductively coupled plasma (ICP).
Abstract: Nonresonant, low-energy atomic oxygen transitions from high-energy (11 to 16 eV) singlet, triplet, and quintet states are observed in the 2 kW argon inductively coupled plasma (ICP). A table of ICP oxygen lines and relative emission intensities from 2500 to 10 000 A is presented. The degree of molecular dissociation in the ICP is evaluated for several small, highly stable molecules as a function of rf power level over the range of 0.2 to 2.25 kW. Quantitative dissociation is achieved at power levels ≥1.95 kW. The use of these nonresonance O(I) lines for the analytical detection of oxygen is reported. The present detection limit for nonoptimized conditions is 0.5 μg. Considerable improvement is expected in the future. The response is linear, and the precision using a gas sampling loop is 0.5% RSD.
TL;DR: In this paper, shock wave compression curves for liquid argon were computed using a number of recently proposed pair potentials and compared to experiment and used to evaluate the accuracy of the repulsive potential.
Abstract: Shock wave compression curves for liquid argon were computed using a number of recently proposed pair potentials. The results are compared to experiment and used to evaluate the accuracy of the repulsive potential. Recent molecular beam results are found to be in excellent agreement with the shock data.
TL;DR: In this article, an investigation of a commercially available three electrode d.c. plasma source burning in an inverted Y configuration was carried out and it was shown that for atoms the position of maximum line intensity in the plasma is determined by the norm temperature of the spectral line.
TL;DR: In this paper, the photoelectrons produced by ionization of argon and xenon atoms with linearly polarized vacuum-ultraviolet radiation of the helium resonance wavelength 58.43 nm have been analyzed simultaneously as to their energy, angle of emission, and spin.
Abstract: The photoelectrons produced by ionization of argon and xenon atoms with linearly polarized vacuum-ultraviolet radiation of the helium resonance wavelength 58.43 nm have been analyzed simultaneously as to their energy, angle of emission, and spin. Degrees of spin polarization up to 0.5 have been found. The results verify the theoretically predicted angular dependence of the photoelectron polarization. The asymmetry parameter $\ensuremath{\beta}$ describing the angular distribution of the cross section is determined via electron intensity and polarization measurements.
TL;DR: In this article, the vapour-liquid equilibrium of the system argon-krypton has been investigated and the coexisting liquid and gas phases have been determined as a function of pressure and temperature.
Abstract: The vapour-liquid equilibrium of the system argon-krypton has been investigated. The co-existing liquid and gas phases have been determined as a function of pressure and temperature. The experimental critical line is compared with theoretical results obtained from perturbation theory and the Van der Waals equation of state.
TL;DR: In this article, the authors investigated the reaction of argon ions with CO, N2, O2, NO, N 2O, CO2, and H2 at different total pressures with a selected ion-drift chamber mass spectrometer.
Abstract: Reactions of argon ions with CO, N2, O2, NO, N2O, CO2, and H2 were investigated at different total pressures with a selected ion‐drift chamber mass spectrometer. The rate data obtained indicate the presence of excited argon ions in addition to argon ions in the ground state. The excited ionic species has been assigned to the 2P1/2 metastable state, and these ions were found to undergo collisional quenching as well as reaction. With CO, N2, and O2 the Ar+(2P1/2) ions react faster than the Ar+(2P3/2) ground state ions and quenching is less significant, while with N2O, CO2, and H2 the Ar+(2P1/2) ions are predominantly quenched. The rate coefficients for the ground state argon ions are in reasonable agreement with recent data obtained by flow techniques. NO provides an exception, the reasons for this observation are discussed.
TL;DR: Among a total of 40 patients reconstriction occurred in 6 cases necessitating a renewal laser evaporization, in these cases the stricture ring was not removed completely down to the wall of the corpus cavernosum urethra.
TL;DR: A simple analytical solution of the equations which govern the formation, collisional relaxation, and mass transport rates of species produced in radially symmetric laser-induced processes is given in this article.
Abstract: A simple analytical solution of the equations which govern the formation, collisional relaxation, and mass transport rates of species produced in radially symmetric laser‐induced processes is given. These equations are specifically applied to the CO2 laser‐induced dissociations of CF2HCl and C2F3Cl dilute in argon. The concentration of the vibrational ground state of the CF2 radical product was probed as a function of time and pressure both during and after the photolyzing laser pulse by the laser‐excited fluorescence technique. From these measurements, the vibrational relaxation rate of ? CF2 in argon was determined to be kVT=2.0×10−15 cm3 sec−1 and its diffusion coefficient was found to be D=90 cm2 Torr sec−1 in argon.