Collision-induced microwave absorption in gaseous mixtures of various rare gases at 2.3 cm−1

1980 ◽  
Vol 58 (5) ◽  
pp. 633-641 ◽  
Author(s):  
I. R. Dagg ◽  
W. D. Leckie ◽  
L. A. A. Read
Keyword(s):  
Microwave Absorption ◽  
Room Temperature ◽  
Infrared Region ◽  
Exponential Model ◽  
Rare Gas ◽  
Rare Gases ◽  
Gaseous Mixtures ◽  
Induced Dipole ◽  
Upper Limits ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 2.3 cm−1 for the rare gas mixtures Ne–Kr, Ar–Kr, Ar–Xe, and Kr–Xe. The absorption coefficient has been measured at room temperature for density products up to 8000 amagat2 and for various density ratios. These results have been used in conjunction with those of the infrared region to determine more accurately the zeroth moment for each of the spectra and hence have allowed improved values for the induced dipole moment parameters for the exponential model. Upper limits to the absorption in He–Xe and He–Ar mixtures in the microwave region have also been established.

Collision-induced microwave absorption in Ne–Xe and Ar–Xe gaseous mixtures

1978 ◽  
Vol 56 (8) ◽  
pp. 1046-1053 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
M. Wong
Keyword(s):  
Absorption Coefficient ◽  
Microwave Absorption ◽  
Low Frequency ◽  
Exponential Model ◽  
Many Body ◽  
Dipole Strength ◽  
Gaseous Mixtures ◽  
A Value ◽  
Induced Dipole ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 4.4 cm−1 for the inert gas mixtures Ne–Xe and Ar–Xe. The absorption coefficient has been measured at room temperature for a range of density products up to 15 000 amagat2 and for different density ratios. The intracollisional absorption coefficient has been determined at this low frequency for each mixture from the data at low densities. These results for the absorption coefficient along with existing infrared results have yielded an accurate value for the zeroth moment for each of the spectra and hence improved values for the induced dipole moment parameters for the exponential model. For the range parameter, ρ, we obtain values of 0.312 Å and 0.408 Å, respectively, for the Ne–Xe and Ar–Xe mixtures. The values for the dipole strength parameters, μσ, calculated using the Lennard-Jones (12-6) potential are 0.0293 and 0.0328 D, respectively. Evaluations of μσ have also been carried out using other potentials. In particular, for Ne–Xe a value of μσ = 0.0377 D is calculated using the more realistic Morse – Spine – van der Waals (MSV) potential. At higher densities the results reveal intercollisional interference effects which result in a reduction of the absorption. The amount of reduction depends on the ratios of the gases in the mixture. In the highest density range studied, there is observed a marked increase in the absorption which may be attributed to many-body collisions.

Collision-induced microwave absorption in Ne–Xe and Ar–Xe gaseous mixtures at 2.3 cm−1

1978 ◽  
Vol 56 (12) ◽  
pp. 1559-1564 ◽  
Author(s):  
I. R. Dagg ◽  
G. E. Reesor ◽  
M. Wong
Keyword(s):  
Absorption Coefficient ◽  
Microwave Absorption ◽  
Line Shape ◽  
Shape Factor ◽  
Room Temperature ◽  
Inert Gas ◽  
Interference Effects ◽  
Many Body ◽  
Gaseous Mixtures ◽  
Density Ratios

Collision-induced microwave absorption has been observed at 2.3 cm−1 for the inert gas mixtures Ne–Xe and Ar–Xe. The absorption coefficient has been measured at room temperature for a range of density products up to 15 000 amagat2 for different density ratios. The present results are compared with the results obtained earlier at 4.4 cm−1. The intracollisional absorption coefficient arising from two body interactions is approximately proportional to the square of the frequency for both mixtures. The intercollisional interference effects have led to a larger suppression of the absorption than was observed previously at 4.4 cm−1. An expression for the intercollisional line shape factor was used to fit the data. At high densities, there is observed a marked increase in the absorption which has also been observed at 4.4 cm−1 and which may be attributed to many body collisions.

Messung der Krypton-85-und Xenon-133-Aktivität der atmosphärischen Luft / A Method for Measurement of the Krypton-85 and Xenon-133-content in the Atmosphere

1977 ◽  
Vol 32 (11) ◽  
pp. 1249-1253 ◽  
Author(s):  
H. Stockburger ◽  
H. Sartorius
Keyword(s):  
Activated Carbon ◽  
Proportional Counter ◽  
Molecular Sieve ◽  
Room Temperature ◽  
Sampling Time ◽  
Rare Gas ◽  
Activity Levels ◽  
Separation And Purification ◽  
Rare Gases ◽  
Xenon 133

AbstractTo measure the 85Kr and 133Xe content in the atmosphere approximately 60 m3 of dried and CO2-removed air are pumped through activated carbon (pressure 300 torr, temperature 77 K) during one week. When sampling time is over, the carbon is heated to 570 K. This gives a gas sample of 41 with more than 90% of the atmospherical krypton and xenon within two hours. With a further step of enrichment, the volume of sample is reduced to 100 ml. The final separation and purification of the rare gases from O2, N2, CO and CO2 is made chromatographically. First the xenon is sepa­rated in a column filled with molecular sieve (5A) at 390 K, after that the krypton is separated in a column with activated charcoal at room temperature with methane as a "carrier gas" and is simultaneously transported to a proportional counter (230 ml). In the first half-year of 1977 the activity levels of 85Kr and 133Xe ran to 17.7 respectively 0.19 pCi/m3 air. The variations of the rare gas-activities are indeed rather high. The xenon-activities are not correlated with the krypton-activities. In a preliminary discussion we try to find reasons for these variations.

Diffusion in multicomponent gaseous mixtures. Part 3

1967 ◽  
Vol 45 (16) ◽  
pp. 1825-1828 ◽  
Author(s):  
Harry Watts
Keyword(s):  
Kinetic Theory ◽  
Multicomponent Mixture ◽  
Equimolar Mixture ◽  
Rare Gas ◽  
Rare Gases ◽  
Binary Diffusion ◽  
Gaseous Mixtures ◽  
Diffusion Systems ◽  
Theory Equation ◽  
Xenon 133

Diffusion of one rare gas into an equimolar mixture of two other rare gases has been followed using krypton-85 or xenon-133 tracer. The systems behave as pseudo-binary diffusion systems. A kinetic theory equation, valid for diffusion of a trace in a multicomponent mixture, is not a good approximation for diffusion of a major component.

Collision-induced absorption in the far infrared region in ethylene – rare gas mixtures

1982 ◽  
Vol 60 (10) ◽  
pp. 1431-1441 ◽  
Author(s):  
I. R. Dagg ◽  
L. A. A. Read ◽  
W. Smith
Keyword(s):  
Fourier Transform ◽  
Far Infrared ◽  
Infrared Region ◽  
Gas Mixtures ◽  
Laser Source ◽  
Rare Gas ◽  
Fourier Transform Spectrometer ◽  
Rare Gases ◽  
Absolute Value ◽  
Far Infrared Laser

The collision-induced spectra of mixtures of ethylene and each of the rare gases He, Ne, Ar, Kr, and Xe in the 40–360 cm−1 region has been obtained using a Michelson Fourier transform spectrometer. In addition, improved results for the collision-induced spectrum of pure ethylene gas are reported using this spectrometer as well as a far infrared laser source. All the results from the pure gas and gas mixtures have been analyzed according to the theory for quadrupolar-induced translation–rotational absorption. From this analysis the following values for the components of the quadrupolar tensor are: Qxx = −3.12, Qvy = 1.55, and Qzz = 1.57 B, which are somewhat lower estimates (in absolute value) than previously reported by us. Evidence for induction by other mechanisms (other than quadrupolar) has been obtained for the He–C2H4 and Ne–C2H4 mixtures.

Rare gas bubbles in muscovite mica implanted with xenon and krypton

1994 ◽  
Vol 9 (12) ◽  
pp. 3095-3107 ◽  
Author(s):  
G.A. Hishmeh ◽  
L. Cartz ◽  
F. Desage ◽  
C. Templier ◽  
J.C. Desoyer ◽  
...  
Keyword(s):  
Room Temperature ◽  
Liquid Nitrogen Temperature ◽  
Amorphous Structure ◽  
Dark Field ◽  
Rare Gas ◽  
Rare Gases ◽  
Transmission Electron ◽  
Dark Field Microscopy ◽  
Muscovite Mica ◽  
Gas Pressures

Xenon and krypton have been implanted into muscovite mica at room temperature and at liquid nitrogen temperature. The behavior of the implanted Xe and Kr was followed by low-temperature transmission electron microscopy and energy dispersive x-ray analysis. An electron diffraction pattern of diffuse bands is observed at room temperature due to the presence of fluid rare gas and to noncrystalline mica. Visible cavities with diameters 10–300 nm formed in the Xe-implanted mica. Visible cavities in room-temperature Kr-implanted mica ranged from 5–50 nm in diameter. The gas pressures at room temperature in the cavities are estimated, assuming all of the implanted gas precipitated in cavities to be ∼10 MPa for Xe and ∼20 MPa for Kr. These pressures are considerably lower than found for rare gases implanted in metals and ceramics, but sufficient to liquefy the rare gases at room temperature. The Xe and Kr were observed by dark-field microscopy to form fcc crystalline solids within the cavities at temperatures below their triple points, with lattice parameters of a(xe) = 0.630 ± 0.0015 nm and a(Kr) = 0.565 ± 0.005 nm. The solid Xe within bubbles was unstable under the electron beam of the transmission electron microscope at temperatures above 80 K, while the solid Kr within bubbles was unstable at temperatures as low as 35 K. The crystalline mica matrix undergoes a transformation from a crystalline structure to an amorphous structure as a result of implantation.

Theory of collision-induced translational absorption

1968 ◽  
Vol 46 (10) ◽  
pp. 1163-1172 ◽  
Author(s):  
V. F. Sears
Keyword(s):  
Dipole Moment ◽  
Line Shape ◽  
Shape Function ◽  
Interatomic Potential ◽  
Exponential Model ◽  
Rare Gas ◽  
Repulsive Core ◽  
Frequency Range ◽  
Induced Dipole ◽  
Binary Collisions

A theory of the line shape for collision-induced translational absorption in rare-gas mixtures is developed. The reduced line-shape function is expanded in terms of the quantity ρ/σ, typically of the order of 0.1, where ρ is the range of the induced dipole moment and σ is the size of the repulsive core of the interatomic potential. The calculation is based on the special properties of the exponential model for the induced electric dipole moment. The temperature is assumed to be sufficiently high that the motion of the atoms can be treated classically, while the density is assumed to be sufficiently low that only binary collisions are important and intercollisional correlation effects are negligible over the frequency range of interest. A least-squares comparison of theory with experiment yields values for ρ and the magnitude of the induced moment for Ne–Ar and He–Ar pairs.

Preparing high purity λ-Ti3O5 and Li/λ-Ti3O5 as a high performance electromagnetic wave absorber

2021 ◽  
Author(s):  
xiankai fu ◽  
Wanqi Chen ◽  
Xiaowen Hao ◽  
Zhimin Zhang ◽  
Ruolan Tang ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Microwave Absorption ◽  
High Purity ◽  
High Performance ◽  
Room Temperature

This paper reports a new candidate material λ-Ti3O5 for microwave absorption. λ-Ti3O5 has been proposed to be metastable and has emerged at room temperature only in the form of nanocrystals....

scholarly journals The Effect Of Thickness on The Optical Properties Of ZnS

2007 ◽  
Vol 4 (4) ◽  
pp. 647-652
Author(s):  
Baghdad Science Journal
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Near Infrared ◽  
High Vacuum ◽  
Ultra Violet ◽  
Infrared Region ◽  
Complex Dielectric Constant ◽  
Film Properties ◽  
Corning Glass ◽  
Different Thickness

Zinc sulfide(ZnS) thin films of different thickness were deposited on corning glass with the substrate kept at room temperature and high vacuum using thermal evaporation technique.the film properties investigated include their absorbance/transmittance/reflectance spectra,band gap,refractive index,extinction coefficient,complex dielectric constant and thickness.The films were found to exhibt high transmittance(59-98%) ,low absorbance and low reflectance in the visible/near infrared region up to 900 nm..However, the absorbance of the films were found to be high in the ultra violet region with peak around 360 nm.The thickness(using optical interference fringes method) of various films thichness(100,200,300,and 400) nm.The band gap measured was found to be in the range (3.52 -3.78 )eV.

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