Showing papers on "Argon published in 1975"
TL;DR: In this paper, an n-channel MOS transistor with palladium gate was fabricated and the threshold voltage of this transistor was found to depend on the partial pressure of hydrogen in the ambient atmosphere.
Abstract: An n‐channel MOS transistor with palladium gate was fabricated. The threshold voltage of this transistor was found to depend on the partial pressure of hydrogen in the ambient atmosphere. At a device temperature of 150 °C, 10 ppm hydrogen in air is easily detected, and in nitrogen or argon the sensitivity is considerably larger. A model, based on hydrogen adsorption on the palladium–silicon dioxide interface, is proposed. This model explains the device behavior and is also able to predict the absolute sensitivity for hydrogen in argon.
467 citations
TL;DR: In this paper, the R-matrix method was used to calculate electron-atom and ion collision cross sections and atomic polarizabilities to enable atomic photoionization processes to be studied.
Abstract: The R-matrix method, which has been used recently to calculate electron-atom and ion collision cross sections and atomic polarizabilities is extended to enable atomic photoionization processes to be studied. Both the initial atomic bound state and the final atomic continuum state are expanded in terms of R-matrix bases. The method is programmed for a general atomic system and then used to calculate the photoionization cross sections of ground state neon and argon atoms leaving the residual ions in their ground or first excited states. Good agreement is obtained with recent experiments using synchrotron radiation both in resonant and non-resonant regions, showing that the method has a wide range of applicability.
226 citations
TL;DR: In this article, the laser-induced fluorescence of ionic states is used to measure local ion densities and velocities in argon plasmas, and the results show that the fluorescence can be used to estimate the local ion density.
Abstract: Laser-induced fluorescence of ionic states is used to measure local ion densities and velocities in argon plasmas.
158 citations
TL;DR: In this article, the rare gas solids neon, argon, krypton, and xenon have been determined to 20 kbar at temperatures from 4.2 K to the triple point.
154 citations
TL;DR: In this article, the emission spectra of XeBr, XeCl and KrF at high pressure were obtained by observing spontaneous emission from electron beam excited mixtures of argon containing lesser amounts of xenon with the halogens or krypton with fluorine.
Abstract: The emission spectra of XeBr, XeCl, XeF, and KrF at high pressure are reported and discussed. The spectra were obtained by observing spontaneous emission from electron beam excited mixtures of argon containing lesser amounts of xenon with the halogens or krypton with fluorine. The emitting state in these species is best described as an ionic species Xe+X− or Kr+F−. The wavelengths of these emission bands are in good agreement with a theoretical model in which the ionic binding energy of the noble gas halide ion pair is roughly equal to that of the nearest alkali halide. Our high pressure spectra imply that the lowest potential energy curve for XeF is bound.
142 citations
TL;DR: In this paper, a band contour model, which makes use of known spectroscopic constantd and the experimental results, satisfactorily accounts for the observed temperature dependence of the absorption coefficient.
Abstract: Mixtures of SF 6 diluted by argon were heated behind an incident shock front in the range 400 to 1500K. Absorption measurements at 11 wavelengths near 10·6 μm were made on the post-shock, equilibrated gas using a CO 2 laser. A band contour model, which makes use of known spectroscopic constantd and the experimental results, satisfactorily accounts for the observed temperature dependence of the absorption coefficient. We are able to estimate the identity of the transitions responsible for absorption of the laser radiation.
129 citations
TL;DR: In this article, cross-beam studies of chemiionization in thermal energy collisions of helium, neon, argon, and krypton metastable atoms with ground state atoms and molecules (Ar, Kr, Xe, N2, H2, O2, NO, CO, CO2, and N2O) are described.
Abstract: Crossed beams studies of chemiionization in thermal energy collisions of helium, neon, argon, and krypton metastable atoms with ground state atoms and molecules (Ar, Kr, Xe, N2, H2, O2, NO, CO, CO2, and N2O) are described. Branching ratios are presented and in some cases absolute total ion production cross sections have been measured.
124 citations
TL;DR: In this article, a semi-empirical model of the deposition rate during reactive sputtering of metals in atmospheres of oxygen and nitrogen in an argon plasma is presented.
117 citations
TL;DR: In this paper, a standard memory function analysis is made of the velocity autocorrelation functions and the main features of the long-time part of the memory function, representing the collective response of the liquid are found to be the same for both species.
Abstract: Molecular-dynamics calculations are reported for binary liquid mixtures formed from neon, argon and krypton. Two groups of computations have been made: those for mixtures of argon and krypton of various compositions at a temperature and volume close to the triple point of krypton, and those for low concentrations of neon in argon at a number of state points. The equilibrium distribution functions are discussed in terms of current conformal-solution theories and deficiencies in these theories are pointed out. The coefficients of self-diffusion are shown to be very well correlated with those of mixtures of hard spheres of appropriate diameters. A standard memory-function analysis is made of the velocity autocorrelation functions and the main features of the long-time part of the memory function, representing the collective response of the liquid, are found to be the same for both species. The relation between the coefficients of mutual diffusion and self-diffusion is also briefly considered.
93 citations
TL;DR: In this paper, the attachment of electrons to CCl4 has been studied in pulse irradiated argon and its admixtures with several atomic and molecular compounds under conditions where the timescale of attachment is comparable with that of electron thermalization using the known energy dependence of the rate constant for attachment.
Abstract: The attachment of electrons to CCl4 has been studied in pulse irradiated argon and its admixtures with several atomic and molecular compounds under conditions where the timescale of attachment is comparable with that of electron thermalization Using the known energy dependence of the rate constant for attachment, the resulting complex electron decay kinetics have been quantitatively related to the energy relaxation process Values of the energy exchange rate coefficient Ku defined by the relationship d?/dt = −Ku⋅[? − (3/2) kT]⋅NM have been determined for 18 compounds of varying complexity and dipole moment The values of Ku found encompass the range from 13×10−13 cm3 sec−1, for argon, to 15×10−8 cm3 sec−1, for acetone The results are compared with energy exchange parameters available from other sources Thermalization times and ranges of electrons in irradiated gaseous and liquid systems are calculated and their relevance to radiation chemistry is discussed
91 citations
TL;DR: In this paper, measurements of the absolute differential cross sections for the elastic scattering of electrons from neon, krypton and xenon for a wide range of electron energies and scattering angles with high angular resolution are presented.
Abstract: For pt.I see ibid., vol.8, no.10, p.1670 (1975). Measurements of the absolute differential cross sections for the elastic scattering of electrons from neon, krypton and xenon for a wide range of electron energies and scattering angles and with high angular resolution are presented. The range of electron energies is 20 to 400 eV, the range of scattering angles from 20 to 150 degrees and the angular resolution of both the incident and scattered electron beams is 1.5 degrees. The experimental method is based on the crossed electron and modulated atom beams techniques. Measured angular distributions have been made absolute by carrying out phase shift analyses over the 19.35 eV (1s2s2)2S resonant state of helium and the 11.10 and 11.27 eV (3s23p54s2), 2P1/2, 2P3/2 resonance doublet in argon coupled with accurate determinations of the beam density ratios of neon, krypton and xenon to helium and argon. The absolute differential cross sections are not consistently in agreement with any previous absolute determinations.
TL;DR: In this paper, a set of valence-force potential constants for methylenimine have been derived from a recent ab initio structural calculation for this molecule, which provide a satisfactory fit to all of the infrared spectroscopic data.
01 Sep 1975
TL;DR: In this article, the authors used measurements of Ar-40 and helium made by the Apollo 17 lunar surface mass-spectrometer for the synthesis of atmospheric supply and loss mechanisms.
Abstract: Measurements of Ar-40 and helium made by the Apollo 17 lunar surface mass-spectrometer are used in the synthesis of atmospheric supply and loss mechanisms. The argon data indicate that about 8% of the Ar-40 produced in the moon due to decay of K-40 is released into the atmosphere and subsequently lost. Variability of the atmospheric abundance of argon requires that the source be localized, probably in an unfractionated, partially molten core. If so, the radiogenic helium released with the argon amounts to 10% of the atmospheric helium supply. The total rate of helium escape from the moon accounts for only 60% of the solar wind particle influx. This seems to require a nonthermal escape mechanism for trapped solar-wind gases, probably involving weathering of exposed soil-grain surfaces by solar-wind protons.
TL;DR: In this article, the emission of boron doped silicon has been studied at oxygen partial pressures between 2 × 10−10 and 2 ×10−5 Torr. Sputtering was done with 2 to 15 keV argon ions at current densities between 3 and 40 μ A cm 2.
TL;DR: In this article, the authors measured the depth profiles of copper-nickel thin film targets with argon and nitrogen primary ions, and found that while pronounced cone formation is observed in case of argon irradiation the erosion is much more uniform with nitrogen projectiles, probably due to formation of nitride surface layers.
Abstract: SIMS depth profiles of copper-nickel thin film targets were measured with argon and nitrogen primary ions. While pronounced cone formation is observed in case of argon irradiation the erosion is much more uniform with nitrogen projectiles, probably due to formation of nitride surface layers.
TL;DR: In this paper, a computer-based method is developed to perform the numerical analysis of the measured adsorption isotherm in order to determine the quantitative distribution of potential energies displayed by a solid substrate for a physically-adsorbed gas.
01 Feb 1975
TL;DR: A FORTRAN IV subprogram called GASP as discussed by the authors calculates the thermodynamic and transport properties for 10 pure fluids: parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide.
Abstract: A FORTRAN IV subprogram called GASP is discussed which calculates the thermodynamic and transport properties for 10 pure fluids: parahydrogen, helium, neon, methane, nitrogen, carbon monoxide, oxygen, fluorine, argon, and carbon dioxide. The pressure range is generally from 0.1 to 400 atmospheres (to 100 atm for helium and to 1000 atm for hydrogen). The temperature ranges are from the triple point to 300 K for neon; to 500 K for carbon monoxide, oxygen, and fluorine; to 600 K for methane and nitrogen; to 1000 K for argon and carbon dioxide; to 2000 K for hydrogen; and from 6 to 500 K for helium. GASP accepts any two of pressure, temperature and density as input conditions along with pressure, and either entropy or enthalpy. The properties available in any combination as output include temperature, density, pressure, entropy, enthalpy, specific heats, sonic velocity, viscosity, thermal conductivity, and surface tension. The subprogram design is modular so that the user can choose only those subroutines necessary to the calculations.
TL;DR: In this article, a model of induction coupled plasma (ICP) discharges is developed for arrangements important in spectrochemical analysis, which accounts for the spatial distribution of gas properties and major energy losses found in high temperature discharges.
TL;DR: In this article, the authors derived the dissociation energies and vibration frequencies of diatomic fluorides, chlorides, and bromides of argon, krypton, and xenon using approximate potential curves and a semiclassical analysis.
TL;DR: In this paper, the reduction of NiX2(PCy3)2 (X = Cl, Br; PCy3 = tricyclohexylphosphine) in toluene with sodium sand under argon affords NiP3(N2) under nitrogen.
TL;DR: In this paper, the pair-potential of argon-krypton and krypton-xenon mixtures was derived from the Barker-Henderson perturbation theory, which has been shown to give good values for the excess thermodynamic properties of mixtures of 6:12 molecules with the contributions of three-body forces and quantum effects included.
Abstract: Recently, reliable pair-potentials have been obtained for argon, krypton and xenon. Pair-potentials of similar form are obtained for the argon-krypton and krypton-xenon interactions. Three parameters are adjusted to give experimental values for the long-range r -6 term and the excess free energy and excess volume for an equimolar liquid mixture at zero pressure and a specified temperature. The excess thermodynamic properties are calculated from the Barker-Henderson perturbation theory, which has been shown to give good values for the excess thermodynamic properties of mixtures of 6:12 molecules, with the contributions of three-body forces and quantum effects included. Excellent agreement with the excess properties of argon-krypton and krypton-xenon mixtures is found at all concentrations.
TL;DR: In this paper, the authors describe measurements of the temperature distribution and the composition of the plasma-MIG arc system using optical spectroscopy and conclude that only a very small part of the wire current flows through the bright inner arc.
Abstract: Describes measurements of the temperature distribution and the composition of the plasma-MIG arc system using optical spectroscopy. It is found that the central part of the arc contains the elements Fe, Mn, Cu, Ca and Ar at a temperature of about 7000K. The outer regions of the arc show only argon spectral lines and have much higher temperature value ( approximately=13000K). From these measurements a number of conclusions can be drawn about the physical properties of the plasma-MIG welding arc. The most important conclusion is that only a very small part of the wire current flows through the bright inner arc.
TL;DR: In this paper, the lifetime spectra for positrons annihilating in helium gas have been measured at room temperature for gas densities up to 60 amagat, and the equilibrium annihilation rate for the free positron component is proportional to the gas density D, in amagats, given by lambda 1=(0.793+or-0.004 D mu s-1 which is equivalent to Zeff=3.94+or 0.02 and is in good agreement with recent calculations.
Abstract: Lifetime spectra for positrons annihilating in helium gas have been measured at room temperature for gas densities up to 60 amagat. The equilibrium annihilation rate for the free positron component is proportional to the gas density D, in amagats, given by lambda 1=(0.793+or-0.004 D mu s-1 which is equivalent to Zeff=3.94+or-0.02 and is in good agreement with recent calculations. The variation of the equilibrium decay rate with gas density for the ortho-positron component is also linear, given by lambda 2=7.24+(0.1006+or-0.0006) D mu s-, which is consistent with pick-off quenching. No other long-lived component has been observed. For neon at room temperature, a shoulder region of width 1700+or-200 ns amagat has been established. Some new measurements for argon, krypton and xenon are also reported. A comparison is made with other recent measurements.
01 Jan 1975
TL;DR: The homogeneous thermal oxidation of methane-oxygen mixtures, highly diluted with argon, was investigated in shock waves by following emission and absorption of various species during the course of the reaction as discussed by the authors.
Abstract: The homogeneous thermal oxidation of methane-oxygen mixtures, highly diluted with argon, was investigated in shock waves by following emission and absorption of various species during the course of the reaction. The equivalence ratio =2[CH 4 ]/[O 2 ] was various from 0.2 to 2.0. The total density extended from 2·10 −5 to 2·10 −3 mole/cm 3 , corresponding to pressures from 3 to 200 atm at 1800 o K. In the present paper data on induction periods for the oxidation of these mixtures are reported for a very wide range of experimental conditions. For mixtures with more than 1% methane and oxygen, and toward higher densities, the following expression describes the induction period τ i − 2.5 · 10 − 15 [ C H 4 ] 0.25 [ O 2 ] − 1.02 [ A r ] 0.0 exp + 222 k J m o l R T [ s ] concentrations in mole/cm 3 For very dilute mixtures the experiments indicate an increase of the apparent activation energies and a change in the concentration dependence of τ i .
TL;DR: In this article, the cross sections for the transfer of up to four electrons in single collisions between multiply charged argon ions (up to Ar7+) and argon atoms are measured.
Abstract: The cross sections for the transfer of up to four electrons in single collisions between multiply charged argon ions (up to Ar7+) and argon atoms are measured. The cross sections ( sigma 21 excepted) show no significant energy dependence in the investigated energy range from 5 to 15 keV times charge state number. Their values are between 4*10-17 cm2 for the transfer of one electron to Ar7+( sigma 76).
TL;DR: In this article, collision-induced emission from S(1S) has been studied for collisions with He, Ar, N2, H2, Kr, and Xe.
Abstract: Collision‐induced emission from S(1S) has been studied for collisions with He, Ar, N2, H2, Kr, and Xe. The S(1S) was made by OCS photodissociation at 1610 A. The emitted intensity increased linearly with the added gas pressure. This behavior can be described by rate coefficients for induced emission on the 1S→1D transition of (5.6±0.9) ×10−20 cm3 molecule−1⋅sec−1 for helium, (4.2±0.3) ×10−18 for argon, (3.3±0.2) ×10−18 for nitrogen, (1.73±0.15) ×10−18 for hydrogen, (1.5±0.1) ×10−17 for krypton, and (1.1±0.05) ×10−16 for xenon. Xenon was also found to enhance the 1S→3P emission intensity with a rate coefficient of (5.5±1.0) ×10−19 cm3 molecule−1⋅sec−1. Induced emission is a major (and possibly exclusive) path for deactivation of S(1S) by all these gases except hydrogen.
TL;DR: In this paper, the authors measured the pressure broadening of the carbon monoxide line near 115 GHz at liquid nitrogen, dry ice, and room temperature, with typical experimental uncertainties of about 10%.
TL;DR: In this article, the authors used an Rf spark−source mass−spectrographic method to analyze the argon content of 12 elementary metals and found that as the atomic mass of the target material increases, the average energy of the reflected energetic argon atoms also increases, leading to the increased argon contents in the film.
Abstract: Sputtered films of 12 elementary metals were analyzed for argon content by an rf spark−source mass−spectrographic method. All films were deposited using dc triode sputtering under similar conditions. Corrections in the data have been made to account for variations in target size and deposition rate. The experimental results are compared with sticking probabilities calculated using the Born−Mayer interatomic potentials; the agreement is fair except for elements having low atomic numbers, e.g., Cu and lower. The data confirm the role of reflected argon atoms in the entrapment mechanism at the substrate—as the atomic mass of the target material increases, the average energy of the reflected energetic argon atoms also increases, leading to the increased argon content in the film. The data also suggest that the entrapped argon content is dependent upon the atomic spacing of the film material.