Search results for "Rotational temperature"
showing 7 items of 17 documents
High-Resolution Jet-Cooled Spectroscopy of SF6: The ν2+ ν6Combination Band of32SF6and the ν3Band of the Rare Isotopomers
1998
The Fourier transform infrared spectrum of SF6 was recorded in a supersonic expansion jet of an SF6/argon mixture. The SF6:Ar seeding ratio was 2:3. The instrumental bandwidth was 0.005 cm-1. A globar source and an MCT detector were used. A rotational temperature of approximately 30 K was achieved. The nu2 + nu6 combination band of 32SF6 was analyzed using a modified version of the spherical top data system (STDS) programs developed in Dijon. A very good fit was obtained for this band with an rms of 0.0036 cm-1. The effective Hamiltonian was developed up to fourth order for the nu2 + nu6 part, to second order for the nu2 and ground state parts, and to first order for the nu6 part. Five hund…
Rotational Transitions of CO+Induced by Atomic Hydrogen
2008
The CO+ molecular ion has been observed in photon-dominated regions. Recent modeling has not been able to explain the abundances of CO+ in these regions. The most abundant collision partners are believed to be hydrogen atoms, hydrogen molecules, and electrons. The reactions of these species with CO+ have been studied previously and found to be fast. The only inelastic processes studied before were collisions of CO+ with electrons. Here we investigate the inelastic collisions of CO+ with hydrogen atoms. We argue that this can be done on the lowest triplet electronic state. This implies that CO+ ions, in a hydrogen atom dominated surrounding, experiences a few inelastic collisions before reac…
The distribution of the rotational transition strength in warm nuclei studied through γ-ray correlations
1995
Abstract The study of damping of rotational motion applying te rotational plane mapping (RPM) method is presented and discussed. The aim of this technique is to extract the distribution of the rotational transition strength from an analysis of the shape of the “central valley” of two- and three-dimensional γ-ray spectra. The method is applied to a triple γ-coincidence data set of 162,163Tm nuclei formed in 37Cl+130Te reactions. The rotational transition strength is obtained as a function of rotational frequency for selected regions of entry states, and the width is found to be rather constant and approximately equal to 80 keV. This value is significantly smaller than the value predicted the…
Determination of gas temperature of high-frequency low-temperature electrodeless plasma using molecular spectra of hydrogen and hydroxyl-radical
2012
Abstract In this study we determine gas temperature of He+H 2 , Ar+H 2 and Ne+H 2 high frequency electrodeless lamps using intensity distribution in rotational spectra of hydrogen molecule and hydroxyl radical. The measurement results show that OH rotational spectra can be successfully used for estimation of gas temperature of the high-frequency electrodeless lamps at very small amounts of hydrogen present in plasma. The analysis of the measurement results leads to the conclusion that in “pure” plasma the applied energy is used to heat plasma, while for the plasma with hydrogen addition the energy is used in chemical reactions.
High-resolution spectroscopy of the ν3 band of WF6 and ReF6 in a supersonic jet
2002
We have recorded the Fourier-transform infrared (FTIR) spectrum of the ν3 fundamental band of WF6 in a continuous supersonic jet expansion with an instrumental bandwidth of 0.0024 cm−1 (FWHM, full width at half maximum, unapodized), using a Bomem DA.002 spectrometer. Some parts of this band have also been recorded with 0.0007 cm−1 bandwidth using a diode laser spectrometer combined with a pulsed slit jet expansion. A multiple-pass arrangement has been used for the slit jet to observe low-intensity lines. In each case, we have used a WF6:He mixture with a seeding ratio 1:3 leading to a rotational temperature of ca. 50 K. This work extends the previous investigation of Takami and Kuze [J. Che…
Spectroscopic studies of Tl containing high frequency electrodeless lamps
2014
In this work we estimate gas temperature from OH rotational spectrum at 306.4 nm and C 2 Swan band at 516.5 nm in thallium containing lamps during two working regimes: stable generation and self-modulation regime. The usage of both molecules allowed us to estimate gas temperature in different zones of the discharge. The measurement results show that the central part of discharge has temperature higher for about 400 K than in vicinity of lamp inner walls. The measurement results of self-modulation regime showed that rotational temperature variations are similar to that of atomic and molecular spectral line intensities with period being around 1 minute. More detailed analysis of temporal beha…
Observation of laser-induced field-free permanent planar alignment of molecules
2011
International audience; Permanent planar alignment of gas-phase linear molecules is achieved by a pair of delayed perpendicularly polarized short laser pulses. The experiment is performed in a supersonic jet, ensuring a relatively high number density of molecules with moderately low rotational temperature. The effect is optically probed on a femtosecond time scale by the use of a third short pulse, enabling a time-resolved birefringence detection performed successively in two perpendicular planes of the laboratory frame. The technique allows for an unambiguous estimation of the molecular planar delocalization produced within the polarization plane of the pulse pair after the turn-off of the…