Search results for "SPECTRA"
showing 10 items of 3542 documents
Preliminary analysis of the pentad of 13CH4 from Raman and infrared spectra
1991
Abstract Preliminary results on the simultaneous analysis of infrared and Raman data of 13 CH 4 in the 3-μm region ( ν 1 , ν 3 , 2 ν 2 , ν 2 + ν 4 , and 2 ν 4 ) are presented. The infrared spectrum of 13 CH 4 (90% enriched) has been recorded with the Fourier transform spectrometer at Kitt Peak National Observatory. Line positions have been measured with a relative accuracy of 0.0001 cm −1 (for well-isolated lines) using 0.0118-cm −1 resolution spectra. In order to compensate for the lack of infrared information about low J transitions of vibrational bands forbidden in infrared, two spectra of the ν 1 ( A 1 ) and 2 ν 2 ( A 1 ) Q branches have been recorded in Dijon by inverse Raman spectrosc…
Signature of quantum interferences in above-threshold detachment of negative ions by a short infrared pulse
2008
Numerical calculations of photodetachment of ${\mathrm{F}}^{\ensuremath{-}}$ irradiated by a linearly polarized strong short infrared pulse have been performed by evaluating the photoelectron ejection probability in the framework of a Keldysh-type approach modified to account for the temporal behavior of the pulse. The results of the calculations are in good agreement with measurements of energy spectra recently appearing in literature, and show features that may be explained in terms of quantum interferences in time domain.
Fine-structure infrared lines from the Cassiopeia A knots
2008
Aims: Archival observations of infrared fine-structure lines of the young Galactic supernova remnant Cassiopeia A allow us to test existing models and determine the physical parameters of various regions of the fast-moving knots (FMKs), which are metal-dominated clouds of material ejected by the supernova explosion. Methods: The fluxes of the far-infrared [O i] and [O iii] lines are extracted from the previously unpublished archival ISO data. The archival Spitzer data are used to determine the fluxes of the O, Ne, Si, S, Ar and Fe ion fine-structure lines originating in the FMKs. The ratios of these line fluxes are used for the plasma diagnostics. We also determine the infrared line flux ra…
The European Photon Imaging Camera on XMM-Newton: The MOS Cameras
2000
The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, defining a circular field of view of 30 arcmin diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A filter wheel carrying three kinds of X-ray transparent light blocking filter, a fully closed, and a fully open position, is fitted to each EPIC instrument. The CCDs are cooled passively and are under full clos…
Construction of the ground state in nonrelativistic QED by continuous flows
2006
AbstractFor a nonrelativistic hydrogen atom minimally coupled to the quantized radiation field we construct the ground state projection Pgs by a continuous approximation scheme as an alternative to the iteration scheme recently used by Fröhlich, Pizzo, and the first author [V. Bach, J. Fröhlich, A. Pizzo, Infrared-finite algorithms in QED: The groundstate of an atom interacting with the quantized radiation field, Comm. Math. Phys. (2006), doi: 10.1007/s00220-005-1478-3]. That is, we construct Pgs=limt→∞Pt as the limit of a continuously differentiable family (Pt)t⩾0 of ground state projections of infrared regularized Hamiltonians Ht. Using the ODE solved by this family of projections, we sho…
MATHEMATICAL MODELLING OF THE SPECTRAL LINE PROFILES IN THE HIGH-FREQUENCY DISCHARGE
1999
Abstract The paper is devoted to an estimation of the true profiles of spectral lines and equipment influence based on complex experimental line shape profiles in high-frequency discharge by means of a non-linear multiparameter chi-square fit. The self-absorption and energy transfer effects are taken into consideration. A good agreement with interferometric data from Hg and Hg–Cd high-frequency electrodeless lamps of both natural and isotopic abundance are achieved. The temperature of radiating atoms and the optical density for several lines are obtained as a function of the high-frequency oscillator working regime. The confidence regions, standard deviations and correlations of parameters …
New neutron-deficient isotopes from $^{78}$Kr fragmentation
2016
In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the fragmentation of a $^{78}$Kr beam allowed the observation of new neutron-deficient isotopes at the proton drip-line. Clean identification spectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were identified for the first time. In addition, $^{59}$Ge was also observed. Three of these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes $^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic…
Precision measurements of the charge radii of potassium isotopes
2019
International audience; Precision nuclear charge radii measurements in the light-mass region are essential for understanding the evolution of nuclear structure, but their measurement represents a great challenge for experimental techniques. At the Collinear Resonance Ionization Spectroscopy (CRIS) setup at ISOLDE-CERN, a laser frequency calibration and monitoring system was installed and commissioned through the hyperfine spectra measurement of $^{38–47}$K. It allowed for the extraction of the hyperfine parameters and isotope shifts with better than 1 MHz precision. These results are in excellent agreement with available literature values and they demonstrate the suitability of the CRIS tec…
Calculation of atomic properties of superheavy elements Z=110–112 and their ions
2020
We calculate the spectra, electric dipole transition rates, and isotope shifts of the superheavy elements Ds ($Z=110$), Rg ($Z=111$), and Cn ($Z=112$) and their ions. These calculations were performed using a recently developed, efficient version of the ab intio configuration-interaction combined with perturbation theory to treat distant effects. The successive ionization potentials of the three elements are also calculated and compared to lighter analogous elements.
Evidence for shock-shock interaction in the jet of CTA 102
2010
We have found evidence for interaction between a standing and a traveling shock in the jet of the blazar CTA 102. Our result is based in the study of the spectral evolution of the turnover frequency-turnover flux density plane. The radio/mm light curves were taken during a major radio outburst in April 2006.