Collision induced absorption and line-mixing effects in the O2 A-band (abstract)

H. Tran; C. Boulet; J. M. Hartmann

doi:10.1063/1.2402788

Collision induced absorption and line-mixing effects in the O₂ A-band (abstract)

H. Tran
, C. Boulet
, J. M. Hartmann

Lab. Interuniversitaire Systemes

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

Abstract

The absorption by oxygen in the region of the O₂ A-band near 760 nm has been measured in the laboratory under various conditions of pressure (20-200 atm) and temperature (200-300 K) for both pure O₂ and O ₂-N₂ mixtures. In order to calculate the contribution of the "allowed" A-band transitions, Lorentzian profiles and a model accounting for line-mixing (LM) effects using the Energy Corrected Sudden (ECS) approximation have been used. The differences between computed spectra and measured values enable extraction of the collision induced absorption (CIA) contribution. It is shown that neglecting line-mixing overestimates absorption in the wings and underestimates absorption at the P and R branch peaks, whereas the CIA extracted by the line-mixing approach shows the "smooth" profile expected. Applying this approach to our spectra enables determination of the CIA and allowed contributions for both O₂-O₂ and O₂-N₂ collisions versus temperature and pressure. The resulting model and data are then used to build a database and some software suitable for the calculation of oxygen (in air) atmospheric absorption and for easy inclusion in radiative transfer codes (available upon request). These tools are then applied to a theoretical study of the influences of both line-mixing and collision induced processes on atmospheric photon path escape factors and on cloud-top altitude retrievals. It is shown LM and CIA make significant contributions and explain a large part of the discrepancies between measured and calculated atmospheric absorption observed recently.

Original language	English
Title of host publication	SPECTRAL LINE SHAPES
Subtitle of host publication	18th International Conference on Spectral Line Shapes
Publisher	American Institute of Physics Inc.
Pages	350
Number of pages	1
ISBN (Print)	0735403708, 9780735403703
DOIs	https://doi.org/10.1063/1.2402788
Publication status	Published - 1 Jan 2006
Externally published	Yes
Event	SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes - Auburn, AL, United States Duration: 4 Jun 2006 → 9 Jun 2006

Publication series

Name	AIP Conference Proceedings
Volume	874
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Conference

Conference	SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes
Country/Territory	United States
City	Auburn, AL
Period	4/06/06 → 9/06/06

Access to Document

10.1063/1.2402788

Cite this

@inproceedings{292cfd6e47db47dc865595c4668ce4b8,

title = "Collision induced absorption and line-mixing effects in the O2 A-band (abstract)",

abstract = "The absorption by oxygen in the region of the O2 A-band near 760 nm has been measured in the laboratory under various conditions of pressure (20-200 atm) and temperature (200-300 K) for both pure O2 and O 2-N2 mixtures. In order to calculate the contribution of the {"}allowed{"} A-band transitions, Lorentzian profiles and a model accounting for line-mixing (LM) effects using the Energy Corrected Sudden (ECS) approximation have been used. The differences between computed spectra and measured values enable extraction of the collision induced absorption (CIA) contribution. It is shown that neglecting line-mixing overestimates absorption in the wings and underestimates absorption at the P and R branch peaks, whereas the CIA extracted by the line-mixing approach shows the {"}smooth{"} profile expected. Applying this approach to our spectra enables determination of the CIA and allowed contributions for both O2-O2 and O2-N2 collisions versus temperature and pressure. The resulting model and data are then used to build a database and some software suitable for the calculation of oxygen (in air) atmospheric absorption and for easy inclusion in radiative transfer codes (available upon request). These tools are then applied to a theoretical study of the influences of both line-mixing and collision induced processes on atmospheric photon path escape factors and on cloud-top altitude retrievals. It is shown LM and CIA make significant contributions and explain a large part of the discrepancies between measured and calculated atmospheric absorption observed recently.",

author = "H. Tran and C. Boulet and Hartmann, \{J. M.\}",

year = "2006",

month = jan,

day = "1",

doi = "10.1063/1.2402788",

language = "English",

isbn = "0735403708",

series = "AIP Conference Proceedings",

publisher = "American Institute of Physics Inc.",

pages = "350",

booktitle = "SPECTRAL LINE SHAPES",

note = "SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes ; Conference date: 04-06-2006 Through 09-06-2006",

}

Tran, H, Boulet, C & Hartmann, JM 2006, Collision induced absorption and line-mixing effects in the O₂ A-band (abstract). in SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes. AIP Conference Proceedings, vol. 874, American Institute of Physics Inc., pp. 350, SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes, Auburn, AL, United States, 4/06/06. https://doi.org/10.1063/1.2402788

Collision induced absorption and line-mixing effects in the O₂ A-band (abstract). / Tran, H.; Boulet, C.; Hartmann, J. M.
SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes. American Institute of Physics Inc., 2006. p. 350 (AIP Conference Proceedings; Vol. 874).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

TY - GEN

T1 - Collision induced absorption and line-mixing effects in the O2 A-band (abstract)

AU - Tran, H.

AU - Boulet, C.

AU - Hartmann, J. M.

PY - 2006/1/1

Y1 - 2006/1/1

N2 - The absorption by oxygen in the region of the O2 A-band near 760 nm has been measured in the laboratory under various conditions of pressure (20-200 atm) and temperature (200-300 K) for both pure O2 and O 2-N2 mixtures. In order to calculate the contribution of the "allowed" A-band transitions, Lorentzian profiles and a model accounting for line-mixing (LM) effects using the Energy Corrected Sudden (ECS) approximation have been used. The differences between computed spectra and measured values enable extraction of the collision induced absorption (CIA) contribution. It is shown that neglecting line-mixing overestimates absorption in the wings and underestimates absorption at the P and R branch peaks, whereas the CIA extracted by the line-mixing approach shows the "smooth" profile expected. Applying this approach to our spectra enables determination of the CIA and allowed contributions for both O2-O2 and O2-N2 collisions versus temperature and pressure. The resulting model and data are then used to build a database and some software suitable for the calculation of oxygen (in air) atmospheric absorption and for easy inclusion in radiative transfer codes (available upon request). These tools are then applied to a theoretical study of the influences of both line-mixing and collision induced processes on atmospheric photon path escape factors and on cloud-top altitude retrievals. It is shown LM and CIA make significant contributions and explain a large part of the discrepancies between measured and calculated atmospheric absorption observed recently.

AB - The absorption by oxygen in the region of the O2 A-band near 760 nm has been measured in the laboratory under various conditions of pressure (20-200 atm) and temperature (200-300 K) for both pure O2 and O 2-N2 mixtures. In order to calculate the contribution of the "allowed" A-band transitions, Lorentzian profiles and a model accounting for line-mixing (LM) effects using the Energy Corrected Sudden (ECS) approximation have been used. The differences between computed spectra and measured values enable extraction of the collision induced absorption (CIA) contribution. It is shown that neglecting line-mixing overestimates absorption in the wings and underestimates absorption at the P and R branch peaks, whereas the CIA extracted by the line-mixing approach shows the "smooth" profile expected. Applying this approach to our spectra enables determination of the CIA and allowed contributions for both O2-O2 and O2-N2 collisions versus temperature and pressure. The resulting model and data are then used to build a database and some software suitable for the calculation of oxygen (in air) atmospheric absorption and for easy inclusion in radiative transfer codes (available upon request). These tools are then applied to a theoretical study of the influences of both line-mixing and collision induced processes on atmospheric photon path escape factors and on cloud-top altitude retrievals. It is shown LM and CIA make significant contributions and explain a large part of the discrepancies between measured and calculated atmospheric absorption observed recently.

U2 - 10.1063/1.2402788

DO - 10.1063/1.2402788

M3 - Conference contribution

AN - SCOPUS:33846984958

SN - 0735403708

SN - 9780735403703

T3 - AIP Conference Proceedings

SP - 350

BT - SPECTRAL LINE SHAPES

PB - American Institute of Physics Inc.

T2 - SPECTRAL LINE SHAPES: 18th International Conference on Spectral Line Shapes

Y2 - 4 June 2006 through 9 June 2006

ER -