Line shape cross sections of HD immersed in HE and H2 gas. I. Pressure broadening cross sections

1987 ◽  
Vol 87 (1) ◽  
pp. 171-181 ◽  
Author(s):  
Joachim Schaefer ◽  
Louis Monchick
Keyword(s):  
Cross Sections ◽  
Line Shape ◽  
Pressure Broadening

Collisional cooling of the NO-He system The pressure broadening cross sections between 4·3 and 1·8 K

1989 ◽  
Vol 67 (2) ◽  
pp. 455-463 ◽  
Author(s):  
Daniel R. Willey ◽  
D.N. Bittner ◽  
Frank C. De Lucia
Keyword(s):  
Cross Sections ◽  
Pressure Broadening ◽  
Collisional Cooling

Experimental and theoretical CO2–Ar pressure-broadening cross sections and their temperature dependence

2001 ◽  
Vol 3 (18) ◽  
pp. 3924-3933 ◽  
Author(s):  
F. Thibault ◽  
B. Calil ◽  
J. Buldyreva ◽  
M. Chrysos ◽  
J.-M. Hartmann ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Cross Sections ◽  
Pressure Broadening

scholarly journals Molecular cross-sections for high-resolution spectroscopy of super-Earths, warm Neptunes, and hot Jupiters

2020 ◽  
Vol 495 (1) ◽  
pp. 224-237 ◽  
Author(s):  
Siddharth Gandhi ◽  
Matteo Brogi ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson ◽  
Phillip A Coles ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Cross Correlation ◽  
High Resolution Spectroscopy ◽  
High Signal ◽  
Pressure Broadening ◽  
Spectral Signatures ◽  
Hot Jupiters ◽  
Wide Range ◽  
Infrared Spectral

ABSTRACT High-resolution spectroscopy (HRS) has been used to detect a number of species in the atmospheres of hot Jupiters. Key to such detections is accurately and precisely modelled spectra for cross-correlation against the R ≳ 20 000 observations. There is a need for the latest generation of opacities which form the basis for high signal-to-noise detections using such spectra. In this study we present and make publicly available cross-sections for six molecular species, H2O, CO, HCN, CH4, NH3, and CO2 using the latest line lists most suitable for low- and high-resolution spectroscopy. We focus on the infrared (0.95–5 μm) and between 500 and 1500 K where these species have strong spectral signatures. We generate these cross-sections on a grid of pressures and temperatures typical for the photospheres of super-Earth, warm Neptunes, and hot Jupiters using the latest H2 and He pressure broadening. We highlight the most prominent infrared spectral features by modelling three representative exoplanets, GJ 1214 b, GJ 3470 b, and HD 189733 b, which encompass a wide range in temperature, mass, and radii. In addition, we verify the line lists for H2O, CO, and HCN with previous high-resolution observations of hot Jupiters. However, we are unable to detect CH4 with our new cross-sections from HRS observations of HD 102195 b. These high-accuracy opacities are critical for atmospheric detections with HRS and will be continually updated as new data become available.

Pressure Effects of Foreign Gases on the 535.0 nm Fluorescence Line of Thallium

1985 ◽  
Vol 40 (8) ◽  
pp. 800-809 ◽  
Author(s):  
E. Lisicki ◽  
A. Bielski ◽  
J. Szudy ◽  
J. Wolnikowski
Keyword(s):  
Cross Sections ◽  
Pressure Effects ◽  
Pressure Broadening ◽  
Fluorescence Line ◽  
Series Of Experiments ◽  
The Cross ◽  
The Impact

Results of a series of experiments on pressure effects caused by various foreign gases on the 535.0 nm Tl fluorescence line emitted due to the photodissociation of TlI-molecules are summarized and some aspects of the Doppler and pressure broadening of this line are discussed. The impact broadening- and shift-cross sections are determined for two sets of mean relative velocities ū of the emitter-perturber pair. An attempt is made to analyse the cross-sections for different perturbers by investigating their dependence on the quantity (α/ū)2/5, where α is the polarizability of the perturber.

Experimental and theoretical CO2–He pressure broadening cross sections

2000 ◽  
Vol 2 (23) ◽  
pp. 5404-5410 ◽  
Author(s):  
F. Thibault ◽  
B. Calil ◽  
J. Boissoles ◽  
J. M. Launay
Keyword(s):  
Cross Sections ◽  
Pressure Broadening

Autoionisation in Atomspektren

1968 ◽  
Vol 23 (1) ◽  
pp. 137-151
Author(s):  
F. J. Comes ◽  
H. G. Sälzer ◽  
G. Schumpe
Keyword(s):  
Numerical Calculation ◽  
Cross Sections ◽  
Line Shape ◽  
Shape Parameter ◽  
Atomic Gases ◽  
Rare Gases ◽  
Rydberg Series ◽  
Ionic States ◽  
Line Shape Parameter ◽  
Absorption Measurements

A detailed discussion of the phenomenon of autoionization and its influence on the absorption spectra of atomic gases is given. Some consideration is devoted to the calculation of cross sections. This theory is applied to the autoionizing Rydberg levels lying above the 2P3/2 threshold of the rare gases krypton and xenon. A numerical calculation is decribed which alows the important parameters of Rydberg series to be calculated. These parameters are the so called unperturbed continuum, the lifetime and oscillator strength of the autoionizing states, the line shape parameter and the quantum defect. From absorption measurements in argon and krypton considerations follow concerning the behaviour of these terms at threshold. A further result of the calculations is the transition probality into the ionic states 2P3/2 and 2P1/2 at the 2P1/2 limit. These values are compared with measured intensities of photoelectrons from a retarding potential experiment.

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.

scholarly journals Absorption cross sections and line shape for the NO3(0–0) band

1982 ◽  
Vol 76 (6) ◽  
pp. 2864-2870 ◽  
Author(s):  
W. J. Marinelli ◽  
D. M. Swanson ◽  
H. S. Johnston
Keyword(s):  
Cross Sections ◽  
Line Shape ◽  
Absorption Cross
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