Institut des Sciences Moléculaires d'Orsay



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Experimental tools


ICARE is a versatile setup which consists in a pulsed molecular beam source coupled to a time-of-flight mass spectrometer. Various radical and ion sources (electric discharge, pyrolysis, laser photolysis, electron gun, laser desorption) can be combined with the skimmed supersonic expansion. The ionization step can be performed by laser (UV multi-photon or VUV one-photon processes) or by electron impact (…)

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INSOLITE (INterstellar SOlids LaboraTory Experiment)

INSOLiTE (INterstellar SOlids LaboraTory Experiment) is an experimental set-up dedicated to the study of the fate of interstellar analogous produced in the lab and characterized by IR spectroscopy when they are irradiated by UV radiation. IINSOLITE set-up

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Cavity Ring Down Spectroscopy (CRDS)

This technique generally consists in measuring the decay time of a laser pulse fired into a rigid high finesse optical cavity made of two highly reflective spherical mirrors. When the cavity is empty, the decay time depends only on the speed of light, on the mirror reflectivity and on the cavity length. When an absorbing specie fills the cavity, the decay time decreases. By measuring the decay time constant for the empty and for the filled cavity, it is therefore possible to obtain the (…)

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Recently, we have initiated the development of a new technique, firstly introduced by Chandler et al [1] and called Dual Etalon Frequency Comb Cavity Ring-Down Spectrometer, but extended to broadband (BB) laser sources. The principle consist in generating two slightly different frequency combs out of two high finesse optical cavities of similar but not equal lengths. Heterodyning is then used to measure the beat notes thanks to the Fourier Transform (FT) analysis of the signal from the (…)

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In this set-up, a flat burner (McKenna) provides flames of premixed hydrocarbon and oxygen gases at various richness’s. Such a laminar flame is a one-dimensional chemical reactor offering a broad range of combustion conditions and sampling of by-products. The burner is installed in a chamber operated at low pressure, typically in the range from 20 to 100 mbar by continuous pumping. The by-products are then extracted by a water cooled quartz cone (hole diameter 0.2-2 mm) inserted into the (…)

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The setup includes a cell containing the photoexcited gas-phase molecules and the FIREFLY (spectrometer dedicated to the measurement of weak IR emission signals). The FIREFLY spectrometer holds narrow bandpass interference circular variable filters, replicated from the ISOCAM instrument onboard of the ISO satellite (1996-1998). The filters have a high transmission (75% at 3.3 μm) and a moderate resolving power (λ/δλ = 45 at 3.3 μm). Specific ellipsoidal mirrors shape the collected IR beam to (…)

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Our instrument is based on a conventional laser flash photolysis method probing the transient absorption. Two specific developments have been introduced. We use a nanosecond supercontinuum light source for the probe laser and 1 or 2 pulsed nanosecond lasers for sequential double-pump probe experiments. An ICCD coupled to a monochromator is used to measure the transient absorption spectra for two cells (pumped + reference cell) simultaneously. General scheme of the Solar-CAPTE (…)

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Experiments are conducted at the Tandem accelerator in Orsay, at IPNO, using the AGAT set-up. Collisions between molecular projectiles (Cn+, CnHm+, CnN+) delivered by the accelerator and rare gas atoms occur in a gaseous jet of known thickness allowing absolute cross sections to be derived. The thickness is varied by changing the flow rate through the jet’s capillary. Fragments produced by dissociation of molecular projectiles in the collision are deflected, according to their charge over (…)

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SSAM (Submillimeter Spectrometer for Astrophysical Molecules)

We have developed a millimeter and submillimeter-wave spectrometer dedicated to the investigation of the rotational spectrum of both stable and reactive species of astrophysical interest. The spectrometer, based on the exploitation of electronic sources and a frequency multiplication chain (VDI), operates in the 75 - 900 GHz region thus matching ideally the current astronomical observations using for instance ALMA and NOEMA.
Several set-ups allowing the production of reactive species can (…)

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In association with the AILES beamline of synchrotron SOLEIL, we developed two absorption cells designed to probe the chemical composition of plasma discharges using synchrotron-based Fourier transform spectroscopy in the far-infrared region. The optical design of both absorption cells is identical and permit to obtain about 24 meter absorption pathlength and these two cells are equipped with electrodes having different configurations. The first set-up is optimized to study the spectra of (…)

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In association with the AILES beamline of synchrotron SOLEIL,, we developed a multipass cell which optics permit to reach about 150 meters absorption pathlength. The set-up is designed to study the rotationally resolved spectra of relatively large C-bearing molecules (such as PAHs, diamondoids, and biphenyls) in the far-IR spectral region using the synchrotron continuum and the Fourier Transform interferometer of the AILES beamline. More generally, the high sensitivity of this experimental (…)

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Laser equipments

TDL+ dye laser (Quantel) pumped by a frequency doubled or tripled nanosecond Nd:YAG laser (Spectra-Physics, Pro-250) delivering 120 mJ at 600 nm, repetition rate 10 Hz. The output of the dye can be doubled and tripled. Optical Parametric Oscillator (MOPO, Spectra-Physics) pumped by a frequency tripled seeded nanosecond Nd:YAG laser (Spectra-Physics, Pro-250) delivering 60 mJ at 500 nm, repetition rate 10 Hz. Broadband OPO (Basiscan, GWU) pumped by a frequency tripled nanosecond Nd:YAG laser (…)

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