N2- and O2-broadening coefficients of C2H2 IR lines

J.P. Bouanich, D. Lambot, G. Blanquet, J. Walrand

Résultats de recherche: Contribution à un journal/une revueArticle

Résumé

Pressure-broadening parameters of six lines belonging to the ν band of CH in collision with N have been measured with a tunable diode-laser spectrometer in order to complete up to J = 33 our earlier measurements (D. Lambot, G. Blanquet, and J. P. Bouanich, J. Mol. Spectrosc.136, 86-92 (1989)) on the broadening of CH by N and O at 297 K. These N- and O-broadening coefficients have been first calculated on the basis of the Anderson-Tsao-Curnutte theory; in this approach, we show that the short-range interactions which contribute significantly to the linewidths are not correctly treated. Next, we consider the improved semiclassical model proposed by Robert and Bonamy. The intermolecular potential consists in the addition of the atom-atom interaction model to the quadrupolar interactions. The limited radial spherical harmonics expansion of the atom-atom potential, from which expressions for the differential cross section were derived, appears to be quite insufficient at short intermolecular distances. Therefore, we use a more accurate representation of this potential, avoiding an inadequate truncation and keeping the analytic expressions obtained by Bonamy and Robert. In the calculations we take into account the contributions derived from the radial functions U(r), U(r), and U(r), as well as from U(r). A theoretical expression is obtained for the U contribution to the differential cross section. The results of the calculations arising from the exact radial expansion of the atom-atom potential appear to be significantly larger for high J lines than those arising from the truncated expansion. The latter results, which do not include adjustable atom-atom parameters, are in good agreement with experimental broadening coefficients for CHO and in reasonable agreement (except at large J values) for CHN. It is also shown that the contributions to the linewidths derived from U are rather small for CHN and more important for CHO. Finally, by calculating the collisional linewidths of CHN and CHO at 200 K, we have predicted their temperature dependences.
langue originaleAnglais
Pages (de - à)195-213
Nombre de pages19
journalJournal of molecular spectroscopy
Volume140
Numéro de publication2
étatPublié - 1 avr. 1990

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Atoms
coefficients
atoms
Linewidth
expansion
methylidyne
laser spectrometers
pressure broadening
cross sections
interactions
spherical harmonics
Semiconductor lasers
Spectrometers
diodes
temperature dependence
collisions
approximation
Temperature

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Bouanich, J.P. ; Lambot, D. ; Blanquet, G. ; Walrand, J. / N2- and O2-broadening coefficients of C2H2 IR lines. Dans: Journal of molecular spectroscopy. 1990 ; Vol 140, Numéro 2. p. 195-213.
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title = "N2- and O2-broadening coefficients of C2H2 IR lines",
abstract = "Pressure-broadening parameters of six lines belonging to the ν band of CH in collision with N have been measured with a tunable diode-laser spectrometer in order to complete up to J = 33 our earlier measurements (D. Lambot, G. Blanquet, and J. P. Bouanich, J. Mol. Spectrosc.136, 86-92 (1989)) on the broadening of CH by N and O at 297 K. These N- and O-broadening coefficients have been first calculated on the basis of the Anderson-Tsao-Curnutte theory; in this approach, we show that the short-range interactions which contribute significantly to the linewidths are not correctly treated. Next, we consider the improved semiclassical model proposed by Robert and Bonamy. The intermolecular potential consists in the addition of the atom-atom interaction model to the quadrupolar interactions. The limited radial spherical harmonics expansion of the atom-atom potential, from which expressions for the differential cross section were derived, appears to be quite insufficient at short intermolecular distances. Therefore, we use a more accurate representation of this potential, avoiding an inadequate truncation and keeping the analytic expressions obtained by Bonamy and Robert. In the calculations we take into account the contributions derived from the radial functions U(r), U(r), and U(r), as well as from U(r). A theoretical expression is obtained for the U contribution to the differential cross section. The results of the calculations arising from the exact radial expansion of the atom-atom potential appear to be significantly larger for high J lines than those arising from the truncated expansion. The latter results, which do not include adjustable atom-atom parameters, are in good agreement with experimental broadening coefficients for CHO and in reasonable agreement (except at large J values) for CHN. It is also shown that the contributions to the linewidths derived from U are rather small for CHN and more important for CHO. Finally, by calculating the collisional linewidths of CHN and CHO at 200 K, we have predicted their temperature dependences.",
author = "J.P. Bouanich and D. Lambot and G. Blanquet and J. Walrand",
note = "Copyright 2008 Elsevier B.V., All rights reserved.",
year = "1990",
month = "4",
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pages = "195--213",
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N2- and O2-broadening coefficients of C2H2 IR lines. / Bouanich, J.P.; Lambot, D.; Blanquet, G.; Walrand, J.

Dans: Journal of molecular spectroscopy, Vol 140, Numéro 2, 01.04.1990, p. 195-213.

Résultats de recherche: Contribution à un journal/une revueArticle

TY - JOUR

T1 - N2- and O2-broadening coefficients of C2H2 IR lines

AU - Bouanich, J.P.

AU - Lambot, D.

AU - Blanquet, G.

AU - Walrand, J.

N1 - Copyright 2008 Elsevier B.V., All rights reserved.

PY - 1990/4/1

Y1 - 1990/4/1

N2 - Pressure-broadening parameters of six lines belonging to the ν band of CH in collision with N have been measured with a tunable diode-laser spectrometer in order to complete up to J = 33 our earlier measurements (D. Lambot, G. Blanquet, and J. P. Bouanich, J. Mol. Spectrosc.136, 86-92 (1989)) on the broadening of CH by N and O at 297 K. These N- and O-broadening coefficients have been first calculated on the basis of the Anderson-Tsao-Curnutte theory; in this approach, we show that the short-range interactions which contribute significantly to the linewidths are not correctly treated. Next, we consider the improved semiclassical model proposed by Robert and Bonamy. The intermolecular potential consists in the addition of the atom-atom interaction model to the quadrupolar interactions. The limited radial spherical harmonics expansion of the atom-atom potential, from which expressions for the differential cross section were derived, appears to be quite insufficient at short intermolecular distances. Therefore, we use a more accurate representation of this potential, avoiding an inadequate truncation and keeping the analytic expressions obtained by Bonamy and Robert. In the calculations we take into account the contributions derived from the radial functions U(r), U(r), and U(r), as well as from U(r). A theoretical expression is obtained for the U contribution to the differential cross section. The results of the calculations arising from the exact radial expansion of the atom-atom potential appear to be significantly larger for high J lines than those arising from the truncated expansion. The latter results, which do not include adjustable atom-atom parameters, are in good agreement with experimental broadening coefficients for CHO and in reasonable agreement (except at large J values) for CHN. It is also shown that the contributions to the linewidths derived from U are rather small for CHN and more important for CHO. Finally, by calculating the collisional linewidths of CHN and CHO at 200 K, we have predicted their temperature dependences.

AB - Pressure-broadening parameters of six lines belonging to the ν band of CH in collision with N have been measured with a tunable diode-laser spectrometer in order to complete up to J = 33 our earlier measurements (D. Lambot, G. Blanquet, and J. P. Bouanich, J. Mol. Spectrosc.136, 86-92 (1989)) on the broadening of CH by N and O at 297 K. These N- and O-broadening coefficients have been first calculated on the basis of the Anderson-Tsao-Curnutte theory; in this approach, we show that the short-range interactions which contribute significantly to the linewidths are not correctly treated. Next, we consider the improved semiclassical model proposed by Robert and Bonamy. The intermolecular potential consists in the addition of the atom-atom interaction model to the quadrupolar interactions. The limited radial spherical harmonics expansion of the atom-atom potential, from which expressions for the differential cross section were derived, appears to be quite insufficient at short intermolecular distances. Therefore, we use a more accurate representation of this potential, avoiding an inadequate truncation and keeping the analytic expressions obtained by Bonamy and Robert. In the calculations we take into account the contributions derived from the radial functions U(r), U(r), and U(r), as well as from U(r). A theoretical expression is obtained for the U contribution to the differential cross section. The results of the calculations arising from the exact radial expansion of the atom-atom potential appear to be significantly larger for high J lines than those arising from the truncated expansion. The latter results, which do not include adjustable atom-atom parameters, are in good agreement with experimental broadening coefficients for CHO and in reasonable agreement (except at large J values) for CHN. It is also shown that the contributions to the linewidths derived from U are rather small for CHN and more important for CHO. Finally, by calculating the collisional linewidths of CHN and CHO at 200 K, we have predicted their temperature dependences.

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