15 research outputs found
RĂ©sonance anharmonique entre v1(A1) et (v 3 + v5 + v6) (A1 + A2) de CH3Br
The 2 930-3 010 cm-1 spectral range has been analyzed under very high resolution (0.005 cm-1). Two bands have been identified : the fundamental parallel band v1 and the parallel component of (v3 + v5 + v6).About 2 600 lines (1 300 for each isotopic species) were assigned. An anharmonic resonance between the levels corresponding to these two bands, has been identified : the K = 5 sub-levels at which the crossing occurs, are shifted by ± 4 cm -1.Le domaine spectral 2 930-3 010 cm-1 a été analysé à l'aide d'un spectre dont la limite de résolution est de 0,005 cm-1. Deux bandes ont été identifiées : la bande fondamentale parallÚle v1 et la composante parallÚle de (v3 + v5 + v6). 2 600 raies au total (1 300 pour chaque variété isotopique) ont été attribuées. On a mis en évidence une résonance anharmonique entre les niveaux correspondant à ces deux bandes ; à l'endroit du croisement (K = 5) les niveaux sont déplacés de ± 4 cm-1
Diode laser spectroscopy of methyl chloride near 14 ÎŒm toward its detection in the stratosphere
Diode laser spectroscopy of methyl chloride near 14 ÎŒm toward its detection in the stratosphere
A first study of the Μ6 fundamental of CF2Cl 2
The spectral region near 923 cm-1 is studied by using diode laser spectra of the dominant Q-branch belonging to the CF2 35Cl2 molecule along with Fourier transform spectra of the entire region from 910 to 935 cm-1. The overlap of the many absorption bands and also the large density of lines make quantum identification difficult because even at the resolving power of the diode laser (0.001 5 cm-1) the lines observed are not pure. However, rotational constants have been found which reconstruct the Q-branch lines up to J = 78. The profile of the R-branch calculated from these constants is in fair agreement with the Fourier transform spectra from 925 to 935 cm-1 recorded at a resolution of 0.04 cm-1.Nous avons effectuĂ© l'Ă©tude spectroscopique de la molĂ©cule CF2 35Cl2 dans la rĂ©gion de 923 cm-1 avec, d'une part, un spectre de laser Ă diode donnant la branche Q de la bande Îœ 6 et, d'autre part, un spectre par transformĂ©e de Fourier de 910 Ă 935 cm-1. La superposition des nombreuses bandes d'absorption dans cette rĂ©gion donne une grande densitĂ© de raies non isolĂ©es qui rend leur identification trĂšs difficile mĂȘme Ă la rĂ©solution du laser Ă diode (0,001 5 cm-1). Nous avons, Ă partir de la branche Q, dĂ©terminĂ© des constantes rotationnelles qui permettent de reproduire les raies jusqu'Ă J = 78. A l'aide de ces constantes, nous avons calculĂ© la branche R et le spectre calculĂ© est en bon accord avec le spectre par transformĂ©e de Fourier enregistrĂ© avec une rĂ©solution de 0,04 cm-1
Infrared Intensities in Methyl Chloride. III. Improvement of the Anharmonic Force Field and the Analysis of the Overtone and Combination Band Intensities
OBSERVATION OF INFRARED SiH in a PLASMA
Author Institution: Laboratoire d'Infrarouge, Universit\'e de Paris-Sud B\hat{a}timent 350; Laboratoire d'Infrarouge, Equipe de Synth\'ese des Couches Minces pour l'Energ\'etique L.P.N.H.E.A preliminary experiment of high resolution absorption and emission spectroscopy of a silane plasma in the range has been previously reported 1 . The detection of the 1-0 band of the free radical SiH, at was then obtained with a poor signal-to-noise ratio. In order to increase the sensitivity of the detection a new experimental set-up has been built. The plasma is observed in a 2.5 m long source containing a White-type multi-reflexion system. The spectra are recorded with the Fourier transform interferometer of Laboratoire dâInfrarouge, with a simultaneous control the conditions of the excitation of the plasma. Description of the experimental system, and preliminary results are given. J.C. Knights, J.P.M Schmitt, J. Perrin and C. Guelachvili, J. Chem . Phys., 76, p.3414-3421 (1982)