Tentative detection of phosphine in IRC+10216

The J,K = 1,0-0,0 rotational transition of phosphine (PH3) at 267 GHz has been tentatively identified with a T_MB = 40 mK spectral line observed with the IRAM 30-m telescope in the C-star envelope IRC+10216. A radiative transfer model has been used to fit the observed line profile. The derived PH3 abundance relative to H2 is 6 x 10^(-9), although it may have a large uncertainty due to the lack of knowledge about the spatial distribution of this species. If our identification is correct, it implies that PH3 has a similar abundance to that reported for HCP in this source, and that these two molecules (HCP and PH3) together take up about 5 % of phosphorus in IRC+10216. The abundance of PH3, as that of other hydrides in this source, is not well explained by conventional gas phase LTE and non-LTE chemical models, and may imply formation on grain surfaces.Comment: 4 pages, 2 figures; accepted for publication in A&A Letter

Analyse globale du cyanoacéthylène (HCCCN) sur base de spectres micro-ondes, submillimétriques, infrarouges et Stark

Doctorat en sciences physiques -- UCL, 199

Millimeter-wave spectra of HCCCN

The rotational spectra of cyanoacetylene (HCCCN) were investigated between 148 and 474 GHz. The assignments were obtained on the basis of a global analysis, which uses both vibrational and rotational data available for this molecule. The 876 new experimental frequencies concern 181 vibrational states (up to about 1750 cm(-1)). The global analysis agreement is perfect for states up to 1300 cm(-1) and the fit remains good for higher energy states. High order anharmonic interactions associated with the k(45577) and k(45666) terms of the potential energy, which are not introduced in our model, are responsible for local effects in a few states. The reduced frequencies are plotted for most reported states to illustrate the effects of the numerous interactions. (C) state-by-state fit is also given, but the classical power series in J(J + 1) is not convenient for the heavily perturbed states. (C) 2000 Elsevier Science B.V. All rights reserved

Caractérisations Chimique et Minéralogique aux Rayons x et Suivi de la Broyabilité des Clinker, Dolérite, Basalte et Métabasalte du Kongo-Central pour une Application Cimentière

International audienc

The v(1) band system of H-CC-CN (cyanoacetylene)

The v(1) band system of cyanoacetylene (H-CC-CN) has been observed with an effective resolution of 0.006 cm(-1) v(1) = 3327.37085(3) cm(-1), B-1 = 0.15149762(2) cm(-1), D-1 = 1.8065(3) x 10(-8) cm(-1). Several hot bands from the states v(5) = 1, v(6) = 1, v(7) = 1, 2 (l = 0 and 2), 3 (l = 1 and 3), and 4 (l = 0 and 2), v(6) = v(7) = 1 (l = 0 and 2), and v(6) = 1 and v(7) = 2 (l = 3) have also been observed and analyzed. Many bands show strong local perturbations due to interactions with states which are combinations of the modes 4, 5, 6, and 7. These perturbing states are also described quantitatively, and rovibrational constants are given. (C) 1996 Academic Press, Inc