High-Resolution Electron-Impact Emission Spectrum of H 2 . I. Cross Sections and Emission Yields 900-1200 Å

High-resolution (Δλ = 115 mA) emission spectra of molecular hydrogen produced by electron-impact excitation at 100 eV have been obtained in the wavelength range 900-1200 A. The emission spectra can be assigned to transitions between the X 1Σ ground state and the 1sσgnpσu 1Σu and 1sσgnpπu 1Πu Rydberg states. Synthetic rotational line spectra based on the excitation function of Liu et al. and calculated 2pσ B 1Σ-X 1Σ, 2pπ C 1Πu-X 1Σ, 3pσ B' 1Σ-X 1Σ, and 3pπD 1Πu-X 1Σ transition probabilities of Abgrall et al. are generally found to be in good agreement with the experimental spectra in the regions where emissions from 1sσgnpσu (n ≥ 4) and 1sσgnpπu (n ≥ 4) states are negligible. Emission cross sections for D 1Π, D' 1Πu, and D'' 1Π, B' 1Σ, and B'' 1Σ states are obtained by measuring the emission intensities from these states relative to those from the B 1Σ,C 1Πu, and D 1Π states. A high- resolution EUV calibration technique is established. At 100 eV the emission cross sections of the D 1Πu, D' 1Πu, D'' 1Πu, B' 1Σ, and B'' 1Σ states are measured to be (2.8 ± 0.4) × 10-18, (6.3 ± 1.3) × 10-19, (5.9 ± 1.7) × 10-20, (2.1 ± 0.3) × 10-18, and (1.6 ± 0.4) × 10-19 cm2, respectively. In addition, the vibrational emission cross sections have been compared to the estimated excitation cross sections to obtain the predissociation yields for selected vibrational levels of the D 1Π, D' 1Π and D'' 1Π states. The B' 1Σ state is inferred to have very significant excitation into the H(1s)+H(2p,2s) dissociative continuum

Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes

We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re

La démence sémantique : éléments du diagnostic précoce [Semantic dementia: aspects of the early diagnosis]

International audienceSemantic dementia is a lobar atrophy syndrome, related to a degeneration of anterior temporal regions, and characterized by a very predominant impairment of semantic memory. Whereas the diagnosis is relatively easy to establish in the typical form and if the patient is seen early, the emergence of possible additional cognitive or psycho-behavioural disorders can lead to a misdiagnosis in favour of a frontotemporal dementia syndrome or even probable Alzheimer's disease

Génération d'un continuum de lumière blanche pour l'analyse spectrale résolue en temps de milieux très diffusants

Cette étude s'inscrit dans le cadre de la mise au point d'une technique de mesure de densité absolue de la molécule SiO, cette dernière intervenant dans la physico-chimie des traitements de film polymère par plasma. Le diagnostic développé est basé sur l'absorption d'un rayonnement U.V. produit par la même molécule que celle à sonder. Nous présentons ici les résultats concernant la mise au point de la source U.V. permettant de produire la fluorescence de SiO. Plusieurs bandes vibrationnelles ainsi que la structure rotationnelle de la transition A-X ont pu être étudiées dans différents gaz porteurs

Increased cognitive asymmetries detects prodomal Alzheimer's disease

International audienc

L’effet des informations de surface sur la dénomination orale d’images : un artéfact ? Apport des analyses intra-individuelles

International audienc