292 research outputs found
Self- and H2-broadened line parameters of carbon monoxide in the first overtone band
No full textIn this study we have re-analyzed high-resolution spectra of pure CO and CO broadened by hydrogen recorded
in the spectral range of the first overtone band.\footnote{V.~Malathy Devi \textit{et al.},
\textit{J.~Mol.~Spectrosc.} \underline{\textbf{228}} (2004) 580-592.} We have used four different line shapes in
the multispectrum analysis (Voigt, speed dependent Voigt,
Rautian, and Rautian with speed dependence) and compared the resulting line shape parameters.
The line mixing coefficients have been calculated
using the Exponential Power Gap and the Energy Corrected Sudden scaling laws.
A classical approach was applied
to calculate CO line widths in CO-H and CO-CO collisions.
The formulas of classical impact theory\footnote{R.~G.~Gordon, \textit{J.~Chem.~Phys.}
\underline{\textbf{44}} (1966) 3083-3089\textit{ibid.}, \underline{\textbf{45}} (1966) 1649-1655.}
are used for calculation of dipole absorption half-widths along with exact 3D Hamilton equations
for simulation of molecular motion. The calculations utilize Monte Carlo averaging over
collision parameters and simple interaction potential (Tipping-Herman + electrostatic).\footnote{J.-P.~Bouanich
and A.~Predoi-Cross, \textit{J.~Molec.~Structure} \underline{\textbf{742}} (2005)
183-190.}\footnote{A.~Predoi-Cross, J.-P.~Bouanich, D.~Chris Benner, A.~D.~May,
and J.~R.~Drummond, \textit{J.~Chem.~Phys.} \underline{\textbf{113}} (2000) 158-168.}
Molecules are treated as rigid rotors. The dependences of CO half-widths on rotational quantum number
are computed and compared with measured data at room temperature.Made available in DSpace on 2017-01-26T21:37:27Z (GMT). No. of bitstreams: 3
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Previous issue date: 2016-06-2
Measured and Theoretical Self- and N₂-Broadened Line Parameters in the ν₆ Band of CH₃D
No full textMonodeuterated methane (CH3D) is a constituent trace species in several planetary atmospheres, and its spectrum is often used in determinations of atmospheric H/D ratios. Methane plays an important role in terrestrial atmospheric chemistry. It is the most abundant hydrocarbon in our atmosphere and as an IR active gas makes an important contribution to the enhanced greenhouse effect. Methane is increasing in the Earth’s atmosphere at a rate of about 1% per year. The current knowledge of its sources and sinks are not sufficient to isolate the cause of the observed changes in the mixing ratio and global distribution. As a result, the infrared spectrum of methane and its isotopomers is continually being investigated in order to obtain improved spectroscopic line parameters needed to interpret remote sensing observations. Remote sensing instruments require laboratory data sets based on measurements of very high accuracy.
The primary objective of this study is to enhance our spectroscopic knowledge of monodeuterated methane in the ν6 band located at 6.8 microns. We present measurement results for self- and N2-broadened line parameters from room temperature down to about 80 K. A total of 23 high-resolution, high S/N spectra recorded with two Fourier transform spectrometers: a) the McMath-Pierce FTS located on Kitt Peak and b) a Bruker IFS-125HR FTS at the Jet Propulsion Laboratory (JPL) 1 were fit simultaneously in a multispectrum approach. 2 The set included both pure CH3D and dilute mixtures of CH3D in research grade nitrogen. The variations in the measured line parameters with the symmetry species, the rotational quantum numbers and with temperature are reported and discussed in comparison with earlier measurements.
For the case of nitrogen-broadening, we also provide semi-classical calculations based on a rigorous treatment of the active molecule as a symmetric top, a model intermolecular potential comprising both short- and long-range interactions, and exact classical trajectories. These calculations are done for various temperatures and for wide ranges of rotational quantum numbers. The role of the various high-order multipoles in the line-broadening at low, middle and high values of the rotational quantum number J is investigated. Main features of the K-dependences are also analyzed. These theoretical values are included in the general comparison of our new experimental and already available in the literature results. 3Poster Session II: June 24, 2014
Temperature-dependence of self- and air-broadened CO line shapes in the fundamental band
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Previous issue date: 2019-06-21"We present results of an extensive analysis of the CO 10 band in 40 spectra of pure carbon monoxide and carbon monoxide mixed with air recorded at temperatures ranging between 79 K and room temperature. All spectra were recorded using the 1-m McMath-Pierce Fourier Transform spectrometer located at Kitt Peak, AZ, USA and two temperature-controlled gas cells.
The analysis was carried out using multispectrum fitting software\footnote{D.~C.~Benner,
C.~P.~Rinsland, V.~Malathy Devi, M.~A.~H.~Smith and
D.~A.~Atkins, \textit{JQSRT} \underline{\textbf{53}} (1995) 705-721.} and the Voigt, speed-dependent Voigt and Rautian line shape models. When using the Rautian model, we employed calculated narrowing parameters obtained from computed diffusion constants\footnote{J.~O.~Hirschfelder, C.~F.~Curtiss and R.~B.~Bird, \underline{Molecular theory of gases and liquids}, New York, Wiley and Sons, 1952.} for each of the absorber-perturber pairs CO-CO, CO-N and CO-O.
The experimentally retrieved temperature dependences of the line shape parameters are been compared with previous published results and with the results of calculations for CO-N.
We thank D.~Chris Benner for the Labfit software. The work of V.~M.~Devi was funded by NASA grants and contracts, and the research by M.~A.~H.~Smith was performed as part of her former employment at NASA Langley Research Center. No official endorsements are intended or implied. N.~Islam and A.~Predoi-Cross have been funded by NSERC. S.~Ivanov received financial support from the Ministry of Science and Higher Education within the State assignment FSRC ""Crystallography and Photonics"" RAS and Russian Science Foundation (Project No.18-55-16006).
MULTISPECTRUM ANALYSIS OF METHANE FROM 4100 TO 4635 CM: SELF- AND AIR-BROADENING COEFFICIENTS (WIDTH AND SHIFTS)
No full text{The research described in this paper was carried out by the Jet Propulsion Laboratory, California Institute of Technology, Langley Research Center and the College of William and Mary under contract with the National Aeronautics and Space Administration. A. Predoi-Cross was supported by the National Sciences and Engineering Research Council of Canada.Author Institution: Department of Physics, The University of Lethbridge, Lethbridge,AB T1K 3M4, Canada; Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109-8099; Department of Physics, The College of William and Mary, Williamsburg,VA 23187-8795Methane plays an important role in atmospheric chemistry, and knowledge of the column distribution leads to a better quantitative understanding of its biogeochemical cycles. To support atmospheric remote sensing of methane, we have measured the air-broadened widths and air-induced pressure shift coefficients for over 1400 transitions of CH belonging to + near 4220 cm, + near 4320 cmand + near 4540 cm. Self-broadening coefficients have been obtained as well. Intercomparisons of broadening coefficients of the various bands have revealed that the widths vary according to both the lower and upper state quantum numbers.
Anaesthesiology trainees and their needs: a Romanian perspective. Results from a European survey
No full textAnaesthesiology training is going through continuous transformations worldwide. Recent data from a European Survey on anaesthesiology postgraduate trainees and their concerns have been published for the first time, following an initiative by the European Society of Anaesthesiology. Among the responders of this survey, 10.8% were represented by Romanian trainees. The main needs of the Romanian anaesthesiology trainees who completed the questionnaire were, in descending order educational contents/EDAIC, technical skills, exchange programmes, residency workload, residency costs and autonomy transition. Another observation coming from the analysed data is that Romanian anaesthesiologists in training are highly concerned and interested in the field of intensive care medicine. The results also pinpoint to the high costs associated with continuous medical education, leading to a high incentive for workforce migration.info:eu-repo/semantics/publishedVersio
Physico-chemical characteristics and antimicrobial studies of silver doped hydroxyapatite
No full textBiocompatible Layers Obtained from Functionalized Iron Oxide Nanoparticles in Suspension
No full textInternational audienceIron oxide nanoparticles have been extensively studied for challenges in applicable areas such as medicine, pharmacy, and the environment. The functionalization of iron oxide nanoparticles with dextran opens new prospects for application. Suspension characterization methods such as dynamic light scattering (DLS) and zeta potential (ZP) have allowed us to obtain information regarding the stability and hydrodynamic diameter of these suspended particles. For rigorous characterization of the suspension of dextran-coated iron oxide nanoparticles (D-MNPs), studies have been performed using ultrasound measurements. The results obtained from DLS and ZP studies were compared with those obtained from ultrasound measurements. The obtained results show a good stability of D-MNPs. A comparison between the D-MNP dimension obtained from transmission electron microscopy (TEM), X-ray diffraction (XRD), and DLS studies was also performed. A scanning electron spectroscopy (SEM) image of a surface D-MNP layer obtained from the stable suspension shows that the particles are spherical in shape. The topographies of the elemental maps of the D-MNP layer showed a uniform distribution of the constituent elements. The homogeneity of the layer was also observed. The morphology of the HeLa cells incubated for 24 and 48 h with the D-MNP suspension and D-MNP layers did not change relative to the morphology presented by the control cells. The cytotoxicity studies conducted at different time intervals have shown that a slight decrease in the HeLa cell viability after 48 h of incubation for both samples was observed
Spectroscopic study of air-broadened nitrous oxide in the ν3 band
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Previous issue date: 6We present results of a recent analysis of laboratory spectra to determine line positions, intensities, _x000d_
air-broadened half-widths and pressure-induced shifts and their temperature dependences _x000d_
in the fundamental band of NO. The spectra used in this study were recorded using _x000d_
the 1-m McMath-Pierce Fourier transform spectrometer while it was located at the National Solar _x000d_
Observatory on _x000d_
Kitt Peak, AZ. Multispectrum analysis softwarefootnote{D.~C.~Benner, C.~P.~Rinsland, _x000d_
V.~Malathy Devi, M.~A.~H.~Smith, D.~Atkins, textit{JQSRT} _x000d_
textbf{53} (1995) 705-721.} was used to retrieve the line parameters using the Voigt _x000d_
and speed-dependent Voigt line profiles. The line mixing coefficients were calculated using the _x000d_
Exponential Power Gap scaling law. Comparisons with similar published results will be presented
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