Low-temperature rate constants for rotational excitation and de-excitation of C3 (X 1∑g +) by collisions with He (1S)

The low-temperature rotational (de-) excitation of C3 (X 1∑g 1) by collisions with He (1S) is studied using an ab initio potential energy surface (PES). This PES has been calculated using the single- and double-excitation coupled-cluster approach with noniterative perturbational treatment of triple excitations [CCSD(T)] and the augmented correlation-consistent triple-ζ basis set (aug-cc-pVTZ) with bond functions. This PES is then incorporated in full close-coupling quantum scattering calculations for collision energies between 0.1 and 50 cm -1 in order to deduce the rate constants for rotational levels of C3 up to j = 10, covering the temperature range 5-15 K. © 2008. The American Astronomical Society. All rights reserved.The Agencia Española de Cooperación Internacional (project A/8083/07, CSIC-Université Tunis El Manar) and the Spanish Ministerio de Educación y Ciencia (project AYA 2005-00702) are thanked for financial supportPeer Reviewe

Cohort Profile: Burden of Obstructive Lung Disease (BOLD) study

The Burden of Obstructive Lung Disease (BOLD) study was established to assess the prevalence of chronic airflow obstruction, a key characteristic of chronic obstructive pulmonary disease, and its risk factors in adults (≥40 years) from general populations across the world. The baseline study was conducted between 2003 and 2016, in 41 sites across Africa, Asia, Europe, North America, the Caribbean and Oceania, and collected high-quality pre- and post-bronchodilator spirometry from 28 828 participants. The follow-up study was conducted between 2019 and 2021, in 18 sites across Africa, Asia, Europe and the Caribbean. At baseline, there were in these sites 12 502 participants with high-quality spirometry. A total of 6452 were followed up, with 5936 completing the study core questionnaire. Of these, 4044 also provided high-quality pre- and post-bronchodilator spirometry. On both occasions, the core questionnaire covered information on respiratory symptoms, doctor diagnoses, health care use, medication use and ealth status, as well as potential risk factors. Information on occupation, environmental exposures and diet was also collected

Spectroscopic and spin-orbit calculations on the SO+ radical cation

International audienceHighly correlated ab initio methods were used in order to generate the potential-energy curves of the SO+ electronic states correlating to S+(S-4(u))+O(P-3(g)) and S+(D-2(u))+O(P-3(g)). These curves were used for deducing accurate spectroscopic properties for these electronic states. Our calculations predict the existence of a (2)Phi state lying close in energy to the well-characterized b (4)Sigma(-) state and several weakly bound quartet and doublet states located in the 6-9 eV internal energy range not identified yet. The spin-orbit integrals between these electronic states were evaluated using these highly correlated wave functions, allowing the discussion of the metastability and the predissociation processes forming S++O in their electronic ground states. Multistep spin-orbit-induced predissociation pathways are suggested. More specifically, the experimentally determined dissociative potential-energy curve [H. Bissantz , Z. Phys. D 22, 727 (1992)] proposed to explain the rapid SO+(b (4)Sigma(-),v >= 13)-> S+(S-4(u))+O(P-3(g)) reaction is found to coincide with the 2 (4)Pi potential-energy curve for short internuclear distances and with the repulsive 1 (6)Pi state for longer internuclear separations. (c) 2006 American Institute of Physics

Étude expérimentale des ailes de la raie 2 537 Å du mercure perturbée par le krypton et le xénon

For atomic densities of krypton and xenon less than 1020 at/cm 3 we have measured the absorption coefficient k(v) of mixtures of mercury-krypton and of mercury-xenon vapours in the range 120-7 500 GHz about the line center v0. At low frequencies, v v0, the k(v) profile shows successive peaks (blue satellites) which can be attributed to bound pairs but their interpretation is not considered in this paper. However, the near wing, although far from the impact approximation domain, cannot be interpreted by the pure quasistatic theory. Taking into account the significant movement of the perturber with respect to the active atom during the interaction period we suggest that this wing can be attributed to the attractive potential branches.On a mesuré le facteur d'absorption k(v) des mélanges vapeur de mercure-krypton et vapeur de mercure-xénon sur un domaine spectral allant de 120 à 7 500 GHz de part et d'autre du centre v0 de la raie, pour des densités atomiques de Kr et Xe inférieures à 1020 at. cm-3. Les caractéristiques du profil spectral de k(v) du côté faibles fréquences font apparaître l'anisotropie du potentiel d'interaction du couple Hg (6 3P1) — gaz perturbateur, aussi bien pour les branches attractives du potentiel (termes de Van der Waals) que pour les branches répulsives. Dans ce domaine v v0 le profil k(v) présente des maxima successifs (satellites bleus) probablement dus à des paires liées et que nous ne cherchons pas à interpréter ici ; mais l'aile proche de v0, bien que située au-delà du domaine de l'approximation d'impact, ne s'interprète pas en théorie quasi statique pure. Nous proposons de l'attribuer aux branches attractives du potentiel, compte tenu d'un déplacement non négligeable du perturbateur par rapport à l'atome actif durant le temps d'intérêt

Sur les potentiels d'interaction Hg (6 1S0) ou Hg (6 3P1) - gaz rares

The first part of this article deals with the experimental study of the line profile of Hg (2 537 Å) perturbed by argon. We give the same interpretation of these experimental data as that given for Hg-Kr and Hg-Xe in a previous publication. Comparison with the results obtained by other authors shows the need to question the meaning of the empirical expression proposed for the representation of interaction-potentials. In the second part we study the theoretical expressions which describe these potentials and in particular we consider the computation of the dipole-induced dipole coefficient of Hg (6 1S0) and Hg (6 3P1) interacting with rare gases. The last part treats only the case of heavy gases. It is shown that it is possible, in some cases, to interpret the coefficients deduced from the experimental data as différences between dipole-induced dipole interaction coefficients.La première partie de cet article concerne l'étude expérimentale du profil de la raie λ = 2 537 Å du mercure perturbé par l'argon. L'interprétation qui est faite des résultats expérimentaux est analogue à celle proposée dans un précédent article pour les perturbateurs krypton et xénon. La confrontation avec les résultats obtenus antérieurement par d'autres auteurs montre la nécessité de s'interroger sur la signification des expressions empiriques proposées pour la représentation des potentiels d'interaction. La seconde partie est consacrée à l'étude des expressions théoriques qui décrivent ces potentiels, en particulier au calcul des coefficients d'interaction dipôle-dipôle induit dans le cas des gaz rares perturbant le mercure dans l'état 6 1S0 ou 6 3P1. Dans la dernière partie, qui concerne uniquement le cas des gaz lourds, on montre qu'il est possible, dans certains cas, d'interpréter les coefficients déterminés dans la première partie comme des différences entre coefficients d'interaction dipôle-dipôle induit

Influence des facteurs intrinsèques anatomiques dans la rupture du ligament croisé antérieur : étude anatomoradiologique comparative

Etude sur les radiographies standard et l'imagerie par résonance magnétique (IRM) de deux facteurs intrinsèques principaux nuisibles au ligament croisé antérieur (mis en évidence par l'étude anatomique et biomécanique de l'aticulation du genou dans la littérature) : une échancrure intercondylienne étroite et une pente tibiale peu important

Stable and metastable states of SN-

International audienc

Experimental study of the mercury 4 047 Å line (6 3P 0-7 3S1) absorption profile in the presence of foreign gases

The absorption profile of the 4 047 Å line of mercury has been studied by means of the magnetic scanning method. The absorption chamber contained either only mercury and nitrogen, or a small amount of nitrogen and a perturbing noble gas.On étudie par balayage magnétique le profil d'absorption de la raie 4 047 Å du mercure. La cuve d'absorption contient soit un mélange de mercure et d'azote, soit un mélange de mercure et de gaz noble, avec une petite quantité d'azote