Pressure broadening of the electric dipole and Raman lines of CO2 by argon: Stringent test of the classical impact theory at different temperatures on a benchmark system

2016 ◽  
Vol 185 ◽  
pp. 48-57 ◽  
Author(s):  
Sergey V. Ivanov ◽  
Oleg G. Buzykin
Keyword(s):  
Electric Dipole ◽  
Pressure Broadening ◽  
Impact Theory ◽  
Different Temperatures ◽  
Stringent Test ◽  
Benchmark System

General Impact Theory of Pressure Broadening

1958 ◽  
Vol 112 (3) ◽  
pp. 855-865 ◽  
Author(s):  
Michel Baranger
Keyword(s):  
Pressure Broadening ◽  
Impact Theory

scholarly journals Dicke Narrowing Reduction of the Doppler Contribution to a Line Width

1981 ◽  
Vol 34 (6) ◽  
pp. 639 ◽  
Author(s):  
DRA McMahon
Keyword(s):  
Dipole Moment ◽  
Line Width ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Line Shape ◽  
Transport Theory ◽  
Diffusion Constant ◽  
Pressure Broadening ◽  
Velocity Changes ◽  
Velocity Moment

In the simplest kinetic models of collisional narrowing or reduction of the Doppler contribution to a spectral line width, the narrowing process is related to the usual diffusion constant of transport theory. Dicke narrowing requires a correlation between the pre- and post-collisional absorber or emitter electric dipole moment. Pressure broadening on the other hand results from at least a partial destruction of this correlation so that in general pressure broadening and Dicke narrowing are statistically dependent on and correlated with each other. It follows that a spectroscopic diffusion constant is required. A classical phase description (which is easily converted to a semiclassical one) is used here to derive a kinetic equation for which the approximate line shape is obtained by It velocity moment method. The spectroscopic diffusion constant closely resembles the Chapman-Enskog first approximation for the diffusion constant but has mixed in an extra function (the memory) which represents the correlation between collision-induced changes of the dipole moment and velocity changes and the correlation between the pre- and post-collision electric dipole moment. Dicke narrowing can be used to obtain information about the line broadening amplitude SB(b, w) for strong velocity-changing collisions. The Galatry ('weak' collision) and 'strong' collision line-shape functions are obtained as different cutoff approximations in the velocity moment analysis. The present analysis, however, is not limited to specifically weak or strong collisions. The two line-shape formulae are shown to be virtually identical sufficiently far from the line centre and at sufficiently high densities. Convenient, approximate analytical formulae for the half-width are obtained using two different definitions.

Diode laser measurements of N2-broadened line widths in the ν1 band of OCS

1985 ◽  
Vol 63 (4) ◽  
pp. 527-531 ◽  
Author(s):  
A. Mouchet ◽  
G. Blanquet ◽  
P. Herbin ◽  
J. Walrand ◽  
C. P. Courtoy ◽  
...  
Keyword(s):  
Diode Laser ◽  
Tunable Diode Laser ◽  
Laser Spectrometer ◽  
Pressure Broadening ◽  
Laser Measurements ◽  
Diode Laser Spectrometer ◽  
Impact Theory ◽  
Line Widths ◽  
Vibration Rotation

A tunable diode laser spectrometer has been used to perform measurements of pressure-broadening coefficients for 20 vibration–rotation lines in the ν1 band of 16O12C32S perturbed by N2. Calculations of these broadening coefficients have been carried out on the basis of the Anderson–Tsao–Curnutte theory and by considering an improved semiclassical impact theory.

An impact theory for Doppler and pressure broadening—I. General theory

1971 ◽  
Vol 11 (10) ◽  
pp. 1547-1565 ◽  
Author(s):  
Earl W. Smith ◽  
J. Cooper ◽  
W.R. Chappell ◽  
T. Dillon
Keyword(s):  
General Theory ◽  
Pressure Broadening ◽  
Impact Theory

Observations oh Nucleation and Growth of Voids in Nickel

1970 ◽  
Vol 28 ◽  
pp. 414-415
Author(s):  
J. L. Brimhall ◽  
H. E. Kissinger ◽  
B. Mastel
Keyword(s):  
High Purity ◽  
Growth Stage ◽  
Elevated Temperatures ◽  
Early Growth ◽  
Nucleation And Growth ◽  
Pure Nickel ◽  
Different Temperatures ◽  
Total Fluence ◽  
Neutron Exposure ◽  
Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

The structure of membranes and membrane proteins embedded in amorphous ice

1992 ◽  
Vol 50 (1) ◽  
pp. 432-433
Author(s):  
Uwe Lücken ◽  
Joachim Jäger
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Membrane Proteins ◽  
Phase Transition Temperature ◽  
Lipid Vesicles ◽  
Freezing Stress ◽  
Amorphous Ice ◽  
Different Temperatures ◽  
Band Pass ◽  
Lipid Polymorphism

TEM imaging of frozen-hydrated lipid vesicles has been done by several groups Thermotrophic and lyotrophic polymorphism has been reported. By using image processing, computer simulation and tilt experiments, we tried to learn about the influence of freezing-stress and defocus artifacts on the lipid polymorphism and fine structure of the bilayer profile. We show integrated membrane proteins do modulate the bilayer structure and the morphology of the vesicles.Phase transitions of DMPC vesicles were visualized after freezing under equilibrium conditions at different temperatures in a controlled-environment vitrification system. Below the main phase transition temperature of 24°C (Fig. 1), vesicles show a facetted appearance due to the quasicrystalline areas. A gradual increase in temperature leads to melting processes with different morphology in the bilayer profile. Far above the phase transition temperature the bilayer profile is still present. In the band-pass-filtered images (Fig. 2) no significant change in the width of the bilayer profile is visible.

Microstructure of sputter deposited Ni-Sb ohmic contacts on GaAs

1989 ◽  
Vol 47 ◽  
pp. 450-451
Author(s):  
S. Yegnasubramanian ◽  
V.C. Kannan ◽  
R. Dutto ◽  
P.J. Sakach
Keyword(s):  
High Performance ◽  
Ohmic Contacts ◽  
Surface Defects ◽  
Pure Metal ◽  
Device Fabrication ◽  
Native Oxide ◽  
Metal Thin Films ◽  
Recent Developments ◽  
Different Temperatures ◽  
Sputter Deposited

Recent developments in the fabrication of high performance GaAs devices impose crucial requirements of low resistance ohmic contacts with excellent contact properties such as, thermal stability, contact resistivity, contact depth, Schottky barrier height etc. The nature of the interface plays an important role in the stability of the contacts due to problems associated with interdiffusion and compound formation at the interface during device fabrication. Contacts of pure metal thin films on GaAs are not desirable due to the presence of the native oxide and surface defects at the interface. Nickel has been used as a contact metal on GaAs and has been found to be reactive at low temperatures. Formation Of Ni2 GaAs at 200 - 350C is reported and is found to grow epitaxially on (001) and on (111) GaAs, but is shown to be unstable at 450C. This paper reports the investigations carried out to understand the microstructure, nature of the interface and composition of sputter deposited and annealed (at different temperatures) Ni-Sb ohmic contacts on GaAs by TEM. Attempts were made to correlate the electrical properties of the films such as the sheet resistance and contact resistance, with the microstructure. The observations are corroborated by Scanning Auger Microprobe (SAM) investigations.

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