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Sample records for broadening line

  1. Stark broadening of B IV spectral lines

    Science.gov (United States)

    Dimitrijević, Milan S.; Christova, Magdalena; Simić, Zoran; Kovačević, Andjelka; Sahal-Bréchot, Sylvie

    2016-08-01

    Stark broadening parameters for 157 multiplets of helium-like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given.

  2. Stark broadening of B IV spectral lines

    CERN Document Server

    Dimitrijevic, Milan S; Simic, Zoran; Kovacevic, Andjelka; Sahal-Brechot, Sylvie

    2016-01-01

    Stark broadening parameters for 157 multiplets of helium like boron (B IV) have been calculated using the impact semiclassical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series. An example of the influence of Stark broadening on B IV lines in DO white dwarfs is given.

  3. Pressure Broadening of Some He I Lines

    Directory of Open Access Journals (Sweden)

    Banaz Omar

    2010-01-01

    Full Text Available Quantum statistical approach is adopted for calculating the spectral line shapes of neutral helium in dense plasmas. Stark broadening of isolated He I lines 5048 Å (21P−41S, 3889 Å (23S−33P, and 3188Å (23S−43P is presented. Based on thermodynamic Green's function, the electronic contribution to the shift and width is considered. The participation of ions to the line broadening is treated in a quasistatic approximation, by taking both quadratic Stark effect and quadrupole interaction into account. The calculated shifts and widths are compared with existing data.

  4. Line broadening and the solar opacity problem

    CERN Document Server

    Krief, M; Gazit, D

    2016-01-01

    The calculation of line widths constitutes a theoretical as well as a computational challenge in the calculation of opacities of hot dense plasmas. Opacity models use line broadening approximations that are untested at stellar interior conditions. Moreover, calculations of atomic spectra nearby the convection zone boundary (CZB) of the sun, indicate a large discrepancy in the K-shell line widths between several atomic codes and the Opacity-Project. In this work, the atomic code STAR is used to study the sensitivity of solar opacities to line-broadening. Atomic spectra of several elements are analyzed and compared within the solar interior. Variations in the solar opacity profile due to changes in the Stark widths are shown to be significant and to result mainly due to K-shell lines. In light of the solar opacity problem, the results are compared with the required opacity variations of the present day sun, as imposed by helioseismic and neutrino observations. It is shown that an increase of the line widths res...

  5. Collisional line broadening in atomic and ionic spectra

    International Nuclear Information System (INIS)

    The collision broadening and shift of the resonance lines of Mg+ (the solar h and k lines), Ca+ (the solar H and K lines) and Sr+, induced by helium and argon, have been measured, together with the singlet resonance lines of the neutral species. The profiles were observed in emission from a flow lamp using a scanning Fabry-Perot interferometer and recorded digitally using a microprocessor-controlled data logging system. Broadening and shift parameters were both obtained by numerical analysis of this data. The new results are augmented by previous measurements in calcium alone and revealing trends through the three consecutive group II elements are established. The observed broadening in argon is in surprisingly good agreement with the predictions of van-der-Waals theory but the shift results do not confirm the presence of any real R-6 long range interaction. (author)

  6. Shape of collision-broadened lines of carbon monoxide

    Science.gov (United States)

    Seleznev, A. F.; Fedoseev, G. V.; Koshelev, M. A.; Tretyakov, M. Yu.

    2015-08-01

    We consider lineshape of the rotational spectrum of a CO molecule under the conditions of prevailing collisional broadening. Several series of experimental data obtained at relatively high (up to 1000) signal-to-noise ratio of self-broadening and broadening by noble gases have been analyzed. We used for analysis several well known models beyond the Voigt profile. It is confirmed that the use of the Hartman-Tran profile needs certain requirements in order to obtain meaningful and unambiguous results. A simple numerical simulation is suggested to evaluate the result of the model usage for any particular set of experimental data. Parameters of the collisional line narrowing were obtained. It is shown that under the experimental conditions, deviations of the shape of the observed lines from the Voigt profile are solely due to the wind effect.

  7. Robust Algorithm for Computing Statistical Stark Broadening of Spectral Lines

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, C A; Sonnad, V

    2010-02-10

    A method previously developed to solve large-scale linear systems is applied to statistical Stark broadened line shape calculations. The method is formally exact, numerically stable, and allows optimization of the integration over the quasi-static field to assure numerical accuracy. Furthermore, the method does not increase the computational effort and often can decrease it compared to the conventional approach.

  8. Quasi-elastic neutron line broadening in nematic liquid crystals

    International Nuclear Information System (INIS)

    On the basis of a new random walk torsional oscillations model of the amplitude φ0 of rigid flat molecules a quasi-elastic neutron line broadening has been calculated and the results compared to the measurements obtained on the sample of cholesteryl propionate. A good agreement was obtained. (author)

  9. Broadening of a spectrum line by finite spectrometer resolution

    International Nuclear Information System (INIS)

    The distortion of a spectrum line by the finite resolving power of a spectrometer is discussed in terms of a mathematical model. Particular attention is given to the case where either a Gaussian or Cauchy slit function broadens an isolated Doppler, Lorentz, or Voigt absorption line. Corrections to the peak absorption, the line width, and the integrated absorption coefficient are calculated and discussed for different combinations of slit functions and line shapes. Several new series expansions for the corrections are derived. Two general FORTRAN IV programs that calculate these corrections are described and some sample correction curves are given. 27 references

  10. Curves of growth for van der Waals broadened spectral lines

    Science.gov (United States)

    Park, C.

    1980-01-01

    Curves of growth are evaluated for a spectral line broadened by the van der Waals interactions during collisions. The growth of the equivalent widths of such lines is shown to be dependent on the product of the perturber density and the 6/10 power of the van der Waals potential coefficient. When the parameter is small, the widths grow as the 1/2 power of the optical depth as they do for the Voigt profile: but when the parameter is large, they grow as 2/3 power and, hence, faster than the Voigt profile. An approximate analytical expression for the computed growth characteristics is given.

  11. Non-thermal line-broadening in solar prominence

    CERN Document Server

    Stellmacher, Goetz

    2016-01-01

    We show that the line broadening in quiescent solar prominences is mainly due to non-thermal velocities. We have simultaneously observed a wide range of optically thin lines in quiescent prominences, selected for bright and narrow Mg\\,b emission without line satellites from macro-shifts. We find a ratio of reduced widths of H-gamma and H-delta of 1.05 +-0.03 which can hardly be attributed to saturation, since both are optically thin for the prominences observed: tau(gamma)<0.3 ; tau(delta)<0.15. We confirm the ratio of reduced widths of He4772(triplet) and He5015(singlet of 1.1 +-0.05 at higher significance and detect a width ratio of Mgb2 and Mg4571 (both from the triplet system) of 1.3 +-0.1. The discrepant widths of lines from different atoms, and even from the same atom, cannot be represented by a unique pair [T_kin ; V_nth]. Values of T_kin deduced from observed line radiance using models, indicate low temperatures down to T_kin~5000K. Non-thermal velocities, related to different physical states of...

  12. Comparing the line broadened quasilinear model to Vlasov code

    Energy Technology Data Exchange (ETDEWEB)

    Ghantous, K. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States); Berk, H. L. [Institute for Fusion Studies, University of Texas, 2100 San Jacinto Blvd, Austin, Texas 78712-1047 (United States); Gorelenkov, N. N. [Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543-0451 (United States)

    2014-03-15

    The Line Broadened Quasilinear (LBQ) model is revisited to study its predicted saturation level as compared with predictions of a Vlasov solver BOT [Lilley et al., Phys. Rev. Lett. 102, 195003 (2009) and M. Lilley, BOT Manual. The parametric dependencies of the model are modified to achieve more accuracy compared to the results of the Vlasov solver both in regards to a mode amplitude's time evolution to a saturated state and its final steady state amplitude in the parameter space of the model's applicability. However, the regions of stability as predicted by LBQ model and BOT are found to significantly differ from each other. The solutions of the BOT simulations are found to have a larger region of instability than the LBQ simulations.

  13. Comparing the line broadened quasilinear model to Vlasov code

    Science.gov (United States)

    Ghantous, K.; Berk, H. L.; Gorelenkov, N. N.

    2014-03-01

    The Line Broadened Quasilinear (LBQ) model is revisited to study its predicted saturation level as compared with predictions of a Vlasov solver BOT [Lilley et al., Phys. Rev. Lett. 102, 195003 (2009) and M. Lilley, BOT Manual. The parametric dependencies of the model are modified to achieve more accuracy compared to the results of the Vlasov solver both in regards to a mode amplitude's time evolution to a saturated state and its final steady state amplitude in the parameter space of the model's applicability. However, the regions of stability as predicted by LBQ model and BOT are found to significantly differ from each other. The solutions of the BOT simulations are found to have a larger region of instability than the LBQ simulations.

  14. Wall-collision line broadening of molecular oxygen within nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Can T.; Lewander, Maerta; Andersson-Engels, Stefan; Svensson, Tomas; Svanberg, Sune [Department of Physics, Lund University, P. O. Box 118, SE-221 00 Lund (Sweden); Adolfsson, Erik [Ceramic Materials, SWEREA IVF, Box 104, SE-431 22 Moelndal (Sweden)

    2011-10-15

    Wall-collision broadening of near-infrared absorption lines of molecular oxygen confined in nanoporous zirconia is studied by employing high-resolution diode-laser spectroscopy. The broadening is studied for pores of different sizes under a range of pressures, providing new insights on how wall collisions and intermolecular collisions influence the total spectroscopic line profile. The pressure series show that wall-collision broadening is relatively more prominent under reduced pressures, enabling sensitive means to probe pore sizes of porous materials. In addition, we show that the total wall-collision-broadened profile strongly deviates from a Voigt profile and that wall-collision broadening exhibits an additive-like behavior to the pressure and Doppler broadening.

  15. Wall-collision line broadening of molecular oxygen within nanoporous materials

    International Nuclear Information System (INIS)

    Wall-collision broadening of near-infrared absorption lines of molecular oxygen confined in nanoporous zirconia is studied by employing high-resolution diode-laser spectroscopy. The broadening is studied for pores of different sizes under a range of pressures, providing new insights on how wall collisions and intermolecular collisions influence the total spectroscopic line profile. The pressure series show that wall-collision broadening is relatively more prominent under reduced pressures, enabling sensitive means to probe pore sizes of porous materials. In addition, we show that the total wall-collision-broadened profile strongly deviates from a Voigt profile and that wall-collision broadening exhibits an additive-like behavior to the pressure and Doppler broadening.

  16. Collisional broadening of depolarized spectral lines of hydrogen gases at low temperatures

    International Nuclear Information System (INIS)

    Experimental results are presented for the collisional broadening and shift of H2, D2 and HD rotational Raman and depolarized Rayleigh lines at various temperatures between 25 K and 300 K. These are then discussed within the context of current theoretical concepts. For a few temperatures the line broadening cross sections are also reported as a function of the ortho-para composition for H2 and D2. (C.F.)

  17. Gain and Raman line-broadening with graphene coated diamond-shape nano-antennas.

    Science.gov (United States)

    Paraskevaidis, Charilaos; Kuykendall, Tevye; Melli, Mauro; Weber-Bargioni, Alexander; Schuck, P James; Schwartzberg, Adam; Dhuey, Scott; Cabrini, Stefano; Grebel, Haim

    2015-10-01

    Using Surface Enhanced Raman Scattering (SERS), we report on intensity-dependent broadening in graphene-deposited broad-band antennas. The antenna gain curve includes both the incident frequency and some of the scattered mode frequencies. By comparing antennas with various gaps and types (bow-tie vs. diamond-shape antennas) we make the case that the line broadening did not originate from strain, thermal or surface potential. Strain, if present, further shifts and broadens those Raman lines that are included within the antenna gain curve. PMID:26332298

  18. Resonance broadening of Hg lines as a density diagnostic in high intensity discharge lamps

    International Nuclear Information System (INIS)

    The use of width measurements on resonance broadened lines of Hg as a density diagnostic in high intensity discharge (HID) lamps is reviewed and further developed in this paper. Optical depths of Hg I lines at 491.6 nm, 577.0 nm, and 1014 nm are computed as a function of temperature to confirm that these lines are optically thin in most HID lamps. The effect of quadratic and quartic radial temperature variation on the width of resonance broadened lines is computed for arc core temperatures from 4000 K to 7000 K. Such variations in temperature, and inverse variations in Hg density, are found to increase the line widths by less than 10% for 'side-on' emission measurements averaged over the arc radius. Theoretical profiles of resonance broadened spectral lines, both radially averaged and as a function of chord offset, are presented. Observations of resonance broadened lines in a metal-halide HID lamp are presented and analysed. It is concluded that the widths of resonance broadened lines provide a convenient and reliable diagnostic for the arc core Hg density but are generally not very sensitive to the radial temperature and Hg density gradient

  19. Resonance broadening of Hg lines as a density diagnostic in high intensity discharge lamps

    Energy Technology Data Exchange (ETDEWEB)

    Lawler, J E [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, WI 53706 (United States)

    2004-05-01

    The use of width measurements on resonance broadened lines of Hg as a density diagnostic in high intensity discharge (HID) lamps is reviewed and further developed in this paper. Optical depths of Hg I lines at 491.6 nm, 577.0 nm, and 1014 nm are computed as a function of temperature to confirm that these lines are optically thin in most HID lamps. The effect of quadratic and quartic radial temperature variation on the width of resonance broadened lines is computed for arc core temperatures from 4000 K to 7000 K. Such variations in temperature, and inverse variations in Hg density, are found to increase the line widths by less than 10% for 'side-on' emission measurements averaged over the arc radius. Theoretical profiles of resonance broadened spectral lines, both radially averaged and as a function of chord offset, are presented. Observations of resonance broadened lines in a metal-halide HID lamp are presented and analysed. It is concluded that the widths of resonance broadened lines provide a convenient and reliable diagnostic for the arc core Hg density but are generally not very sensitive to the radial temperature and Hg density gradient.

  20. Supersonic Line Broadening within Young and Massive Super Star Clusters

    OpenAIRE

    Tenorio-Tagle, G.; Wunsch, R.; Silich, S.; Munoz-Tunon, C.; Palous, J.

    2009-01-01

    The origin of supersonic infrared and radio recombination nebular lines often detected in young and massive superstar clusters are discussed. We suggest that these arise from a collection of repressurizing shocks (RSs), acting effectively to re-establish pressure balance within the cluster volume and from the cluster wind which leads to an even broader although much weaker component. The supersonic lines are here shown to occur in clusters that undergo a bimodal hydrodynamic solution (Tenorio...

  1. SUPERSONIC LINE BROADENING WITHIN YOUNG AND MASSIVE SUPER STAR CLUSTERS

    International Nuclear Information System (INIS)

    The origin of supersonic infrared and radio recombination nebular lines often detected in young and massive superstar clusters is discussed. We suggest that these arise from a collection of repressurizing shocks (RSs), acting effectively to re-establish pressure balance within the cluster volume and from the cluster wind which leads to an even broader although much weaker component. The supersonic lines here are shown to occur in clusters that undergo a bimodal hydrodynamic solution, that is within clusters that are above the threshold line in the mechanical luminosity or cluster mass versus the size of the cluster plane. A plethora of RSs is due to frequent and recurrent thermal instabilities that take place within the matter reinserted by stellar winds and supernovae. We show that the maximum speed of the RSs and of the cluster wind are both functions of the temperature reached at the stagnation radius. This temperature depends only on the cluster heating efficiency (η). Based on our two-dimensional simulations we calculate the line profiles that result from several models and confirm our analytical predictions. From a comparison between the predicted and observed values of the half-width zero intensity of the two line components, we conclude that the thermalization efficiency in young super star clusters above the threshold line must be lower than 20%.

  2. Pressure shift and broadening of the 254-nm intercombination line of mercury by N2

    International Nuclear Information System (INIS)

    We have used laser absorption spectroscopy to study the collisional broadening and shift of the 254-nm 6 1S0→6 3P1 intercombination line of Hg in the presence of N2 for pressures below 400 Torr. This study comprises the first measurements of the proportionality constants for pressure broadening and shift of Hg due to N2 in this pressure range, and the first high-precision measurements of these pressure effects on Hg for any foreign gas. We obtain -2.54(2) MHz/Torr for the shift and 9.01(4) MHz/Torr for the broadening (full width at half maximum) at 21 degree sign C (95% confidence interval). These results are important for ongoing experiments using optical pumping of mercury in tests of fundamental symmetries, as well as for characterization of interatomic forces and tests of the theory of collisional line broadening

  3. Shift and broadening of resonance lines of the antiprotonic helium atoms in liquid He-4

    OpenAIRE

    Adamczak, Andrzej; Bakalov, Dimitar

    2013-01-01

    The shift and broadening of the resonance lines in spectrum of the antiprotonic helium atoms $\\bar{p}\\mathrm{He}^{+}$ located in fluid and superfluid $^4$He have been calculated. The contributions to the shift and broadening from collective degrees of freedom in liquid $^4$He have been estimated using the phenomenological response function. Effects due to the interaction of $\\bar{p}\\mathrm{He}^{+}$ with a single $^4$He atom have been calculated in the quasistatic approximation using the exper...

  4. An experimental investigation into power broadening of the Na-D lines in a flame

    International Nuclear Information System (INIS)

    Investigations are described aimed at the verification of the existence of power broadening in fluorescence, as predicted by theory in the case of a broadband excitation source. Measurements were performed on a vapour of sodium (Na) atoms in a pre-mixed H2-O2-Ar flame under 1 atm pressure. The easily excited first resonance (or D) lines of Na were chosen for the observation of power broadening in fluorescence. (Auth.)

  5. Absorption spectra of broadened sodium resonance lines in presence of rare gases

    International Nuclear Information System (INIS)

    The pressure broadening of alkali-metal lines is a fundamental problem with numerous applications. For example, the sodium resonance lines broadened by xenon are important in the production of broad spectra emitted in the HPS (High-Pressure Sodium) lamp and they potentially can be used for gas condition diagnostics. Broadened absorption lines of alkali-metal atoms are prominent in the optical spectra of brown dwarfs and understanding the broadening mechanism will help elucidate the chemical composition and atmospheric properties of those stars. The far-line wing spectra of sodium resonance lines broadened by rare gases are found to exhibit molecular characteristics such as satellites and hence the total absorption coefficients for vapors of Na atoms and perturbing rare gas atoms can be modeled as Na-RG (rare gas) molecular absorption spectra. In this work, using carefully chosen interatomic potentials for Na-RG molecules we carry out quantum-mechanical calculations for reduced absorption coefficients for vapors composed of Na-He, Na-Ar, and Na-Xe. Calculated spectra are compared to available experimental results and the agreement is good in the measured satellite positions and shapes

  6. Study of ion line broadening in the Tormac discharge

    International Nuclear Information System (INIS)

    Tormac (Toroidal Magnetic Cusp) is a magnetic confinement plasma concept having absolute minimum-B geometry. Two versions of Tormac are considered here. Tormac T IV-c has a glass vessel of rectangular cross section, 0.5 m in diameter. The confinement field rises to approx. 4.5 kG in approx. 8.3 μsec. Tormac T V has a T-shaped glass vessel, 1 m in diameter, with a field of approx. 3 kG, rising in approx. 10 μsec. Gaussian HeII 4686 A spectral lines having full widths at half maximum over 2 A have been observed in both Tormac plasmas

  7. Laser-Induced Optical Breakdown in Methane: Diagnostic Using H-Gamma Line Broadening

    Directory of Open Access Journals (Sweden)

    Christian G. Parigger

    2010-01-01

    Full Text Available Measurements and analysis are reported of Stark-broadened profiles of the H-gamma line emitted from plasma formed by Laser-Induced Optical Breakdown (LIOB in a pulsed methane flow. Electron densities Ne are deduced for 18 instants of time in the range between 0.4 and 2.1 microseconds after LIOB and for 2 different gas pressures. The obtained values of Ne are in a good agreement with the corresponding values found previously from Stark-broadened profiles of the H-alpha and H-beta lines.

  8. The role of intermediate coupling in the Stark broadening of isolated ion lines

    International Nuclear Information System (INIS)

    In the case of spectral lines arising from states of high orbital angular momentum, the Russell-Saunders (LS) coupling approximation will not be valid in general. However, because of the summation over a complete set of perturbing levels in Stark broadening calculations, the observable effects of the breakdown of LS coupling should be greatly reduced in practice. An attempt is made to decide whether a critical experiment is feasible, which aims specifically to demonstrate coupling effects in the Stark broadening of isolated ion lines by plasmas

  9. Variable rotational line broadening in the Be star Achernar

    CERN Document Server

    Rivinius, Th; Townsend, R H D; Carciofi, A C; Štefl, S

    2013-01-01

    The main theoretical problem for the formation of a Keplerian disk around Be stars is how to supply angular momentum from the star to the disk, even more so since Be stars probably rotate somewhat sub-critically. For instance, nonradial pulsation may transport angular momentum to the stellar surface until (part of) this excess supports the disk formation/replenishment. The nearby Be star Achernar is presently building a new disk and offers an excellent opportunity to observe this process from relatively close-up. Spectra from various sources and epochs are scrutinized to identify the salient stellar parameters characterizing the disk life cycle as defined by H\\alpha emission. Variable strength of the non-radial pulsation is confirmed, but does not affect the further results. For the first time it is demonstrated that the photospheric line width does vary in a Be star, by as much as \\Delta v sin i \\lesssim 35kms^{-1}. However, contrary to assumptions in which a photospheric spin-up accumulates during the diskl...

  10. Improved electron collisional line broadening for low-temperature ions and neutrals in plasma modeling

    International Nuclear Information System (INIS)

    In this study, electron collisional broadening of observed spectral lines depends on plasma electron temperature and density. Including this effect in models of measured spectra is necessary to determine plasma conditions; however, computational limits make accurate line broadening treatments difficult to implement in large-scale plasma modeling efforts. In this paper, we report on improvements to the treatment of electron collisional line broadening and illustrate this with calculations using the Los Alamos ATOMIC code. We implement the Dimitrijevic and Konjevic modified semi-empirical model Dimitrijevic and Konjevic (1986 Astron. and Astrophy. 163 297 and 1987 Astron. Astrophys. 172 345), which we amend by employing oscillator strengths from Hartree-Fock calculations. This line broadening model applies to near-neutral plasmas with electron temperatures of Te ~ 1 eV and electron densities of Ne ~1017 cm-3. We evaluate the D.K.-inspired model against the previous hydrogenic approach in ATOMIC through comparison to NIST-rated measurements for selected neutral and singly-ionized Ca, O, Fe, and Sn lines using both fine-structure and configuration-averaged oscillator strengths. The new D.K.-inspired model is significantly more accurate than the previous hydrogenic model and we find the use of configuration-averaged oscillator strengths a good approximation for applications such as LIBS (laser induced breakdown spectroscopy), for which we demonstrate the use of the D.K.-inspired model

  11. Estimate of the J'J'' dependence of water vapor line broadening parameters

    International Nuclear Information System (INIS)

    The dependence of water line broadening coefficients on the 'good' quantum numbers - angular momentum and symmetry of the upper and lower levels - is analyzed for rotational quantum numbers up to J=50. Trends are investigated separately for P-, Q-, and R-branch transitions for the atmospherically important isotopologue of water. Results are presented which were obtained using two different methods: By averaging the broadening coefficients from HITRAN-2008 for small J values and also by averaging of data calculated using a semi-empirical method for higher J. The resulting air-broadening coefficients allow water vapor spectra with millions of weak lines to be calculated with an accuracy reasonable for many applications, for example estimation of sun radiation with low resolution. Sample results of calculations are presented.

  12. Line broadening in the PXRD patterns of layered hydroxides: The relative effects of crystallite size and structural disorder

    Indian Academy of Sciences (India)

    Grace S Thomas; P Vishnu Kamath

    2006-01-01

    Layered hydroxides crystallize in a hexagonal structure and incorporate a number of different types of structural disorders as an exigency of anisotropic bonding. Structural disorder contributes to the non-uniform broadening of lines in the powder X-ray diffraction pattern. Common among the disorders are stacking faults, which broaden the ℎ0ℓ/0ℓ reflections. Interstratification selectively broadens the 00ℓ reflections and turbostratic disorder broadens the 0ℓ reflections. The line broadening caused by structural disorder has to be discounted before estimates of particle size are made by applying the Scherrer formula.

  13. LBQ2D, Extending the Line Broadened Quasilinear Model to TAE-EP Interaction

    Science.gov (United States)

    Ghantous, Katy; Gorelenkov, Nikolai; Berk, Herbert

    2012-10-01

    The line broadened quasilinear model was proposed and tested on the one dimensional electrostatic case of the bump on tailfootnotetextH.L Berk, B. Breizman and J. Fitzpatrick, Nucl. Fusion, 35:1661, 1995 to study the wave particle interaction. In conventional quasilinear theory, the sea of overlapping modes evolve with time as the particle distribution function self consistently undergo diffusion in phase space. The line broadened quasilinear model is an extension to the conventional theory in a way that allows treatment of isolated modes as well as overlapping modes by broadening the resonant line in phase space. This makes it possible to treat the evolution of modes self consistently from onset to saturation in either case. We describe here the model denoted by LBQ2D which is an extension of the proposed one dimensional line broadened quasilinear model to the case of TAEs interacting with energetic particles in two dimensional phase space, energy as well as canonical angular momentum. We study the saturation of isolated modes in various regimes and present the analytical derivation and numerical results. Finally, we present, using ITER parameters, the case where multiple modes overlap and describe the techniques used for the numerical treatment.

  14. Calculation of the density shift and broadening of the transition lines in pionic helium: Computational problems

    Energy Technology Data Exchange (ETDEWEB)

    Bakalov, Dimitar, E-mail: dbakalov@inrne.bas.bg [Bulgarian Academy of Sciences, INRNE (Bulgaria)

    2015-08-15

    The potential energy surface and the computational codes, developed for the evaluation of the density shift and broadening of the spectral lines of laser-induced transitions from metastable states of antiprotonic helium, fail to produce convergent results in the case of pionic helium. We briefly analyze the encountered computational problems and outline possible solutions of the problems.

  15. On quantum-mechanical unified theories of collisional spectral line broadening

    NARCIS (Netherlands)

    Schuller, F.; Nienhuis, G.

    1982-01-01

    We compare the Baranger-type unified theory of line broadening with a quantum version of the binary-collision approach. For the simple model system of a two-state atom, where both treatments are well-defined, the binary-collision theory results only from the exact formalism after an inversion of an

  16. Study of stark broadening of high-Z hydrogenic ion lines in dense hot plasmas

    International Nuclear Information System (INIS)

    Stark broadened x-ray line profiles from highly ionized hydrogenic ions, radiating while immersed in a hot dense plasma, are studied. The broadening effects produced by the ions present in the plasma are treated through the use of static electric microfield distribution functions. The microfield distribution functions employed have the following properties: (1) the radiating hydrogenic ion may have any net charge; (2) the perturbing ions and electrons in the plasma may have different kinetic temperatures; and (3) two species of ions, of charge z1 and z2, may be present in any given ratio

  17. Ion Dynamics Effect on Stark-Broadened Line Shapes: A Cross-Comparison of Various Models

    Directory of Open Access Journals (Sweden)

    Sandrine Ferri

    2014-07-01

    Full Text Available Modeling the Stark broadening of spectral lines in plasmas is a complex problem. The problem has a long history, since it plays a crucial role in the interpretation of the observed spectral lines in laboratories and astrophysical plasmas. One difficulty is the characterization of the emitter’s environment. Although several models have been proposed over the years, there have been no systematic studies of the results, until now. Here, calculations from stochastic models and numerical simulations are compared for the Atoms 2014, 2 300 Lyman-α and -β lines in neutral hydrogen. Also discussed are results from the Helium-α and -β lines of Ar XVII.

  18. Stark broadening of the 1640- and 4686-A lines of ionized helium

    International Nuclear Information System (INIS)

    The Stark-broadened profiles of the 1640- and 4686-A lines of ionized helium have been calculated using an approximation to the electron broadening operator in the unified classical-path theory of Smith, Vidal, and Cooper. The approximation is such that the results reproduce the time-ordered impact-theory results in the line center, and the ionized-radiator quasistatic results in the far wings. Sample calculations at n/sub e/ = 10/sup 17/ cm/sup -3/ and T = 40 000 degreeK are found to give significantly more narrow profiles than the corresponding modified-impact-theory results because of a different treatment of the lower-state interaction. Indirect comparison with experiment indicates that the calculated lines are too narrow, but it is expected that the inclusion of neglected effects of ion dynamics and inelastic collisions would improve agreement

  19. Plasma motions and non-thermal line broadening in flaring twisted coronal loops

    CERN Document Server

    Gordovskyy, Mykola; Browning, Philippa

    2015-01-01

    Observation of coronal EUV spectral lines offers an opportunity to evaluate the thermal structure and flows in flaring atmospheres. This, in turn, can be used to estimate the partitioning between the thermal and kinetic energies released in flares. Our aim is to forward-model large-scale (50-10000 km) velocity distributions in order to interpret non-thermal broadening of different spectral EUV lines observed in flares. The developed models allow us to understand the origin of the observed spectral line shifts and broadening, and link these features to particular physical phenomena in flaring atmospheres. We use ideal MHD to derive unstable twisted magnetic fluxtube configurations in a gravitationally-stratified atmosphere. The evolution of these twisted fluxtubes is followed using resistive MHD, with anomalous resistivity depending on the local density and temperature. The model also takes into account the thermal conduction and radiative losses. The model allows us to evaluate average velocities and velocity...

  20. Stark broadening measurement of the beta Paschen line of the hydrogen in a linear discharge

    International Nuclear Information System (INIS)

    The stark broadening of the beta Paschen line of the hydrogen is determined from the profile measurements of the emitted line in a helium plasma with 0,5% of hidrogen. The plasma is a pulsed linear discharge generated by a damped oscillatory current with peak intensity of 20 kA. Electronic densities are determined from the 4471A sup(o) line of the HeI. The profiles are measured by the display to display method, utilizing a 75 cm focal distance monochromator and an InSb detector. The results obtained are compared with semiclassical calculations. (L.C.)

  1. The variable temperature pressure broadening and line shift of CO and HDO in collision with helium

    International Nuclear Information System (INIS)

    Pressure broadening and line shift cross sections for the 1 left-arrow 0 and 2 left-arrow 1 rotational transitions of carbon monoxide (CO) in collision with Helium (He) have been measured between 1 and 600 K. Measurements below 30 K were made using the collisional cooling technique, while measurements at higher temperatures were made in an equilibrium cell. The experimental apparatus and techniques employed in the study are described. The data are compared with theoretical predictions, and the significant differences between predictions based on the best available potential energy surface and the experimental results are discussed. Recent studies of the pressure broadening and line shifting of the 110 left-arrow 111 rotational transition of deuterated water (HDO) in collision with He will also be presented

  2. Collisional shift and broadening of the transition lines in pionic helium

    Science.gov (United States)

    Obreshkov, Boyan; Bakalov, Dimitar

    2016-06-01

    We calculate the density shift and broadening of selected dipole transition lines of pionic helium in gaseous helium at low temperatures up to T =12 K and pressure up to a few bars. In the approximation of binary collisions the shift and broadening depend linearly on the density; we evaluate the slope of this linear dependence for a few spectral lines of known experimental interest and also investigate its temperature dependence. We find a blueshift of the resonance frequencies of the (n ,l )=(16 ,15 )→(16 ,14 ) , (17 ,16 )→(17 ,15 ) , and (16 ,15 )→(17 ,14 ) unfavored transitions and a redshift for the favored one, (17 ,16 )→(16 ,15 ) . The results are intended to significantly increase the efficiency of the laser spectroscopy investigations of pionic helium and help with the interpretation of the experimental data.

  3. Collisional shift and broadening of the transition lines in pionic helium

    CERN Document Server

    Obreshkov, Boyan

    2016-01-01

    We calculate the density shift and broadening of selected dipole transition lines of pionic helium in gaseous helium at low temperatures up to T=12 K and pressure up to a few bar. In the approximation of binary collisions the shift and broadening depend linearly on the density; we evaluate the slope of this linear dependence a few spectral lines of known experimental interest, and also investigate its temperature dependence. We find blue shift of the resonance frequencies of the $(n,l)=(16,15) \\rightarrow (16,14) $, $(17,16) \\rightarrow (17,15)$, and $(16,15)\\rightarrow(17,14)$ transitions, and red shift for the favored transition $(17,16) \\rightarrow (16,15)$. The results are intended to significantly increase the efficiency of the laser spectroscopy investigation of pionic helium and help the interpretation of the experimental data.

  4. Power-law temperature dependence of collision broadening and shift of atomic and molecular rovibronic lines

    International Nuclear Information System (INIS)

    The classical phase-shift theory of spectral line shapes is used to examine various aspects of the applicability of the power-law relations to the description of temperature variations of pressure broadening and shifting coefficients of the isolated atomic and rovibronic molecular lines in a wide temperature range. Model calculations performed for potentials of the Lennard-Jones type indicate that the temperature dependence exponents of the broadening and shifting can be related to the details of the intermolecular interactions. It is shown that they are sensitive to the range of temperatures assumed in the fit and therefore extreme care must be taken when the power-law temperature dependence is used as a scaling law. The problems of the failure of the power-law and of variations in the sign of pressure shift coefficients with increasing temperature are discussed. Very good fits of Frost's empirical formula for temperature dependence of pressure shift to the theoretical ones are obtained. -- Highlights: ► Classical theory of line shapes is used to examine the power-law relations. ► The broadening and shifting exponents depend on the range of temperatures in the fit. ► Extreme care must be taken when using the power-law dependence as a scaling law

  5. Electron Stark Broadening Database for Atomic N, O, and C Lines

    Science.gov (United States)

    Liu, Yen; Yao, Winifred M.; Wray, Alan A.; Carbon, Duane F.

    2012-01-01

    A database for efficiently computing the electron Stark broadening line widths for atomic N, O, and C lines is constructed. The line width is expressed in terms of the electron number density and electronatom scattering cross sections based on the Baranger impact theory. The state-to-state cross sections are computed using the semiclassical approximation, in which the atom is treated quantum mechanically whereas the motion of the free electron follows a classical trajectory. These state-to-state cross sections are calculated based on newly compiled line lists. Each atomic line list consists of a careful merger of NIST, Vanderbilt, and TOPbase line datasets from wavelength 50 nm to 50 micrometers covering the VUV to IR spectral regions. There are over 10,000 lines in each atomic line list. The widths for each line are computed at 13 electron temperatures between 1,000 K 50,000 K. A linear least squares method using a four-term fractional power series is then employed to obtain an analytical fit for each line-width variation as a function of the electron temperature. The maximum L2 error of the analytic fits for all lines in our line lists is about 5%.

  6. Dispersion corrections to the Gaussian profile describing the Doppler broadening of spectral lines

    Science.gov (United States)

    Wójtewicz, S.; Wcisło, P.; Lisak, D.; Ciuryło, R.

    2016-04-01

    A dispersionally corrected Gaussian profile describing Doppler-broadened spectral line shapes is presented. Proposed corrections include the frequency dependence of the Doppler shifting caused by dispersion as well as by light frequency variation over the whole spectral line shape. It is shown that the frequency dependence of the Doppler shifting can have a non-negligible influence on the line-shape model and can affect the line shape even at the relative level of 10-5. Moreover, this effect also influences the determination of the line position at the level of kilohertz. Finally, the impact of the presented results on the Doppler width thermometry and precise molecular spectroscopy for fundamental studies is emphasized.

  7. Fast H-alpha line broadening during the 100 ns REB injection into a plasma

    International Nuclear Information System (INIS)

    Profiles of the Hα line emitted from hot electron plasma Te>>Ti during the 100 ns REB injection resemble the Gaussian profiles from neutrals with a temperature Tn(t)∼Ti(t)∼Te(t) rapidly growing up to 30 eV. A combination of Doppler and Stark effects of the intense ion sound waves - remnants of the burned out Langmuir cavitons - is suggested for a plausible explanation of this fast Hα line broadening. The reliability is thus also indirectly supported of the basic ideas of strong Langmuir turbulence for the description of REB-plasma systems. (author) 3 figs., 7 refs

  8. Stark Broadening of several Ar I Spectral Lines in the Visible Part of the Spectrum

    CERN Document Server

    Dimitrijevic, Milan S; Simic, Zoran; Sahal-Brechot, Sylvie

    2012-01-01

    In order to complete data on Stark broadening parameters for Ar I line in the visible spectrum, we determined Stark widths and shifts due to electron, proton, and ionized helium impacts, for nine lines (4191.0, 4259.4, 5912.1, 6043.2, 6045.0, 6752.9, 7503.9, 7514.6, 7724.2 {\\AA}), using jK coupling and semiclassical-perturbation theory. The obtained results will enter the STARK-B database, which is a part of Virtual Atomic and Molecular Data Center.

  9. Effects of ion dynamics and opacity on Stark-broadened argon line profiles

    International Nuclear Information System (INIS)

    We examine the combined effects of ion dynamics and opacity on line profiles used in the analysis of hot dense plasmas. Specifically, we have calculated Stark-broadened line profiles for resonance and satellite lines of highly stripped Ar ions both in the static ion approximation and including the effects of ion dynamics. Using the results of a kinetics computer code combined with an escape factor approximation to account for the effects of radiative transfer, we have calculated the relative intensities of these lines as well as the effects of opacity on their profiles. The resulting theoretical spectrum is used in the analysis of data obtained from a series of experiments performed at the Laboratory for Laser Energetics in which plastic microballoons filled with D2 and doped with Ar were imploded using the Omega laser system. Typical core conditions at stagnation were ne=1x1024 cm-3, kT=900 eV. Varying the relative concentration of Ar in D2 provides an opportunity to study the combined and individual effects of ion motion and opacity on Stark-broadened line profiles. copyright 1996 The American Physical Society

  10. Stark Broadening of in III Lines in Astrophysical and Laboratory Plasma

    CERN Document Server

    Simic, Z; Kovacevic, A B; Sahal-Brechot, S

    2012-01-01

    Besides the need of Stark broadening parameters for a number of problems in physics, and plasma technology, in hot star atmospheres the conditions exist where Stark widths are comparable and even larger than the thermal Doppler widths. Using the semiclassical perturbation method we investigated here the influence of collisions with charged particles for In III spectral lines. We determined a number of Stark broadening parameters important for the investigation of plasmas in the atmospheres of A-type stars and white dwarfs. Also, we have compared the obtained results with existing experimental data. The results will be included in the STARK-B database, the Virtual Atomic and Molecular Data Center and the Serbian Virtual Observatory.

  11. Stark Broadening of several Ne II, Ne III and O III Spectral Lines for the Stark-B Database

    CERN Document Server

    Dimitrijevic, Milan S; Simic, Zoran; Sahal-Brechot, Sylvie

    2012-01-01

    In order to complete Stark broadening data for Ne II, and O III lines, needed for analysis of stellar atmospheres, we determined, within the semiclassical perturbation method, the missing Stark broadening parameters for the broadening by collisions with protons and ionized helium, for 15 Ne II and 5 O III multiplets. Also, electron, proton, and ionized helium impact broadening parameters for an important Ne II multiplet in the visible part of the spectrum, and for three Ne III multiplets, were calculated. The obtained data will be included in the STARK-B database, which is a part of Virtual Atomic and Molecular Data Center.

  12. Stark broadening of high-principal-quantum-number n-alpha lines of hydrogen.

    Science.gov (United States)

    Lasalle, T. R.; Nee, T.-J.; Griem, H. R.

    1973-01-01

    High n-alpha lines (transitions n + 1 to n) with quantum numbers n between 50 and 250 have been observed emanating from galactic H II regions where the electron density and temperature are about 1000/cu cm and 1 eV, respectively. High n-alpha lines have not previously been seen in the laboratory where fairly homogeneous plasmas may be produced and relatively precise measurements of electron densities and temperatures can be made. The present work describes experiments where the first members of the hydrogen line series with lower states n = 10, 11, 12, and 13 have been detected in a laboratory plasma. The width of the 12-alpha line at 88.7 microns could be measured and was consistent with calculated broadening from elastic electron collisions and quasi-static ion effects.

  13. Theoretical study of the Stark broadening for Mg IV spectral lines of astrophysical interest

    Science.gov (United States)

    de Andrés-García, I.; You, C.; Alonso-Medina, A.; Colón, C.

    2016-08-01

    Emission lines of Mg IV have been detected in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of LS V +46º21 star and in the Space Telescope Imaging Spectrograph (STIS) spectrum of BD +28º4211 star. This fact justifies our interest in providing spectroscopic parameters of Mg IV. Stark broadening parameters for 169 spectral lines of Mg IV have been calculated by using the Griem semi-empirical approach. The matrix elements used in these calculations has been determined from 13 configurations of Mg IV: 2s12p6, 2s22p4ns (n = 3-5), 2s22p4nd (n = 3-5) and 2s22p45g for even parity and 2s22p5, 2s22p4np (n = 3, 4) and 2s22p4nf (n = 4, 5) for odd parity. Our calculations were made by using the Cowan code. Data are presented for an electron density of 1017 cm-3 and temperatures T = 1.0-10.0 (104 K). Also we present calculated values of transition probabilities for 30 spectral lines and radiative lifetimes corresponding to its upper levels. These values were analyzed using the data found in the literature. Theoretical trends of the Stark broadening parameters versus the temperature for several lines of astrophysical interest are presented.

  14. Self- and CO2-broadened line shape parameters for infrared bands of HDO

    Science.gov (United States)

    Smith, Mary-Ann H.; Malathy Devi, V.; Benner, D. Chris; Sung, Keeyoon; Mantz, Arlan W.; Gamache, Robert R.; Villanueva, Geronimo L.

    2015-11-01

    Knowledge of CO2-broadened HDO line widths and their temperature dependence is required to interpret infrared spectra of the atmospheres of Mars and Venus. However, this information is currently absent in most spectroscopic databases. We have analyzed nine high-resolution, high signal-to-noise spectra of HDO and HDO+CO2 mixtures to obtain broadening coefficients and other line shape parameters for transitions of the ν2 and ν3 vibrational bands located at 7.13 and 2.70 μm, respectively. The gas samples were prepared by mixing equal amounts of high-purity distilled H2O and 99% enriched D2O. The spectra were recorded at different temperatures (255-296 K) using a 20.38 cm long coolable cell [1] installed in the sample compartment of the Bruker IFS125HR Fourier transform spectrometer at the Jet Propulsion Laboratory in Pasadena, CA. The retrieved HDO spectroscopic parameters include line positions, intensities, self- and CO2-broadened half-width and pressure-induced shift coefficients and the temperature dependences for CO2 broadening. These spectroscopic parameters were obtained by simultaneous multispectrum fitting [2] of the same interval in all nine spectra. A non-Voigt line shape with speed dependence was applied. Line mixing was also observed for several transition pairs. Preliminary results compare well with the few other measurements reported in the literature.[1] K. Sung et al., J. Mol. Spectrosc. 162, 124-134 (2010).[2] D. C. Benner et al., J. Quant. Spectrosc. Radiat Transfer 53, 705-721 (1995).The research performed at the College of William and Mary was supported by NASA’s Mars Fundamental Research Program (Grant NNX13AG66G). The research at Jet Propulsion Laboratory, California Institute of Technology, Connecticut College, Langley Research Center, and Goddard Space Flight Center was conducted under contracts and cooperative agreements with the National Aeronautics and Space Administration. RRG is pleased to acknowledge support of this study by the

  15. On quantum-mechanical unified theories of collisional spectral line broadening

    OpenAIRE

    Schuller, F.; Nienhuis, G.

    1982-01-01

    We compare the Baranger-type unified theory of line broadening with a quantum version of the binary-collision approach. For the simple model system of a two-state atom, where both treatments are well-defined, the binary-collision theory results only from the exact formalism after an inversion of an integration variable in an integral equation. On the other hand, the binary-collision theory is applicable to more general systems. In the limiting cases of the impact and the quasistatic theories,...

  16. Refinement of the semiclassical theory of the Stark broadening of hydrogen spectral lines in plasmas

    International Nuclear Information System (INIS)

    Stark broadening (SB) of hydrogen, deuterium, and tritium lines (H-lines) is an important diagnostic tool for many applications. The most “user-friendly” are semiclassical theories of the SB of H-lines: their results can be expressed analytically in a relatively simple form for any H-line. The simplest semiclassical theory is the so-called Conventional Theory (CT), which is frequently referred to as Griem's theory. While by now there are several significantly more advanced semiclassical “non-CT” theories of the SB, Griem's CT is still used by a number of groups performing laboratory experiments or astrophysical observations for the comparison with their experimental or observational results. In the present study we engage unexplored capabilities of the CT for creating analytically a more accurate CT. First, we take into account that the perturbing electrons actually do not move as free particles: rather they move in a dipole potential V=〈R〉·r/r3, where r is the radius-vector of the perturbing electrons and 〈R〉 is the mean value of the radius vector of the atomic electron. Second, Griem's definition of the so-called Weisskopf radius was not quite accurate. Third, in his book of year 1974, Griem suggested changing so-called strong collision constant without changing the Weisskopf radius, while in reality the choices of the Weisskopf radius and of the strong collision constant are interrelated. We show that the above refinements of the CT increase the electron broadening – especially for warm dense plasmas emitting H-lines. By comparison with benchmark experiments concerning the Hα line we demonstrate that the effect of the ion dynamics (neglected in any CT) might be slightly smaller than previously thought, while the effect of the acceleration of perturbing electrons by the ion field in the vicinity of the radiating atom (neglected in any CT) might be greater than previously thought. - Highlights: • Perturbing electrons actually

  17. Magnetic Turbulence and Line Broadening in Simulations of Lyman-Alpha Absorption

    Science.gov (United States)

    Gurvich, Alex; Burkhart, Blakesley K.; Bird, Simeon

    2016-01-01

    We use the Illustris cosmological AREPO simulations to study the effects of gas turbulence and magnetic fields on measurements from the Lyman-Alpha forest. We generate simulated Lyman-Alpha spectra and plot the distributions of Column Density (CDD) and Doppler Width (b) both by adhering to the canonical method of fitting Voigt profiles to absorption lines and by directly measuring the column density and equivalent widths from snapshot data .We investigate the effects of additional unresolved gas turbulence in Illustris by adding an additional broadening term to the line profiles to mimic turbulent broadening. When we do this, we find a measurable effect in the CDD and an offset in the mean of the b distribution corresponding to the additional turbulence. We also compare different MHD runs in AREPO we find that the CDD can measurably differentiate between magnetic seed field at redshifts as low as z=0.1, but we do not find that the b distribution is affected at a detectable level. Our work suggests that the effects of turbulence and magnetic fields from z=2-0.1 can potentially be measured with these diagnostics. This work was supported in part by the NSF REU and DoD ASSURE programs under NSF grant no. 1262851 and by the Smithsonian Institution.

  18. Self and N2 collisional broadening of far-infrared methane lines measured at the SOLEIL synchrotron

    International Nuclear Information System (INIS)

    Following our recent study devoted to measurements of intensities of pure rotation lines of methane, room temperature far infrared spectra of methane diluted in nitrogen at five total pressures between 100 and 800 hPa have been recorded at the AILES beamline of the SOLEIL synchrotron. One hundred and five N2 broadening coefficients of methane pure rotation lines have been measured in the 83–261 cm−1 spectral range using multi-spectrum non-linear least squares fitting of Voigt profiles. Pressure-induced line shifts were not needed to fit the spectra to the noise level and line mixing effects were neglected. One hundred and seventy-six self broadening coefficients have also been measured in the 59–288 cm−1 spectral range using the pure methane spectra recorded in our previous work. The measured N2 broadening coefficients were compared to semi-classical calculations. -- Highlights: ► Self and N2 broadening coefficients measured for pure rotation lines of 12CH4. ► Spectra recorded at the AILES beamline of the SOLEIL synchrotron. ► First measurements of broadening coefficients in the THz spectrum of methane. ► N2 broadening coefficients calculated using a modified Robert–Bonamy formalism.

  19. Fluctuation broadening of the plasma resonance line in the vortex liquid state of layered superconductors

    International Nuclear Information System (INIS)

    The Josephson plasma resonance (JPR) provides a sensitive probe of vortex states in layered superconductors. We demonstrate that in the case of weak damping in the liquid phase, broadening of the JPR line is caused mainly by random Josephson coupling arising from the density fluctuations of pancake vortices. In this case the JPR line has the universal shape, which is determined only by parameters of the superconductors and temperature. This mechanism gives a natural explanation for the experimentally observed asymmetric lineshape. The tail at high frequencies arises due to mixing of the propagating plasma modes by random Josephson coupling, while the tail at small frequencies is caused by the localized plasma modes originating from a rare fluctuation suppression of the Josephson coupling in large areas. copyright 1999 The American Physical Society

  20. Shift and broadening of emission lines in Nd$^{3+}$:YAG laser crystal influenced by input energy

    Indian Academy of Sciences (India)

    POURMAND SEYED EBRAHIM; REZAEI GHASEM

    2016-06-01

    Spectroscopic properties of the flashlamp-pumped Nd$^{3+}$:YAG laser as a function of input energy were studied over the range of 18–75 J. The spectral widths and shifts of quasi-three-level and four-level inter-Stark emissions within the respective intermanifold transitions of $^4$F$_{3/2}$ $\\rightarrow$ $^{4}$I$_{9/2} $ and $^{4}$F$_{3/2}$ $\\rightarrow$ $^{4}$I$_{11/2}$ were investigated. The emission lines of $^{4}$F$_{3/2}$ $\\rightarrow$ $^{4}$I$_{9/2}$ shifted towards longer wavelength (red shift) and broadened, while the positions and linewidths of the $^{4}$F$_{3/2}$ $\\rightarrow$ $^{4}$I$_{11/2}$ transition lines remained constant by increasing the pumping energy. This is attributed to the thermal population as well as one-phonon and multiphonon emission processes in the ground state. This phenomenon degrades the output performance of the lasers.

  1. Plasma motions and non-thermal line broadening in flaring twisted coronal loops

    Science.gov (United States)

    Gordovskyy, M.; Kontar, E. P.; Browning, P. K.

    2016-05-01

    Context. Observation of coronal extreme ultra-violet (EUV) spectral lines sensitive to different temperatures offers an opportunity to evaluate the thermal structure and flows in flaring atmospheres. This, in turn, can be used to estimate the partitioning between the thermal and kinetic energies released in flares. Aims: Our aim is to forward-model large-scale (50-10 000 km) velocity distributions to interpret non-thermal broadening of different spectral EUV lines observed in flares. The developed models allow us to understand the origin of the observed spectral line shifts and broadening, and link these features to particular physical phenomena in flaring atmospheres. Methods: We use ideal magnetohydrodynamics (MHD) to derive unstable twisted magnetic fluxtube configurations in a gravitationally stratified atmosphere. The evolution of these twisted fluxtubes is followed using resistive MHD with anomalous resistivity depending on the local density and temperature. The model also takes thermal conduction and radiative losses in the continuum into account. The model allows us to evaluate average velocities and velocity dispersions, which would be interpreted as non-thermal velocities in observations, at different temperatures for different parts of the models. Results: Our models show qualitative and quantitative agreement with observations. Thus, the line-of-sight (LOS) velocity dispersions demonstrate substantial correlation with the temperature, increasing from about 20-30 km s-1 around 1 MK to about 200-400 km s-1 near 10-20 MK. The average LOS velocities also correlate with velocity dispersions, although they demonstrate a very strong scattering compared to the observations. We also note that near footpoints the velocity dispersions across the magnetic field are systematically lower than those along the field. We conclude that the correlation between the flow velocities, velocity dispersions, and temperatures are likely to indicate that the same heating

  2. - and Air-Broadened Line Shape Parameters of 12CH_4 : 4500-4620 CM-1

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Brown, Linda; Crawford, Timothy J.; Smith, Mary Ann H.; Mantz, Arlan; Predoi-Cross, Adriana

    2014-06-01

    Accurate knowledge of spectral line shape parameters is important for infrared transmission and radiance calculations in the terrestrial atmosphere. We report the self- and air-broadened Lorentz widths, shifts and line mixing coefficients along with their temperature dependences for methane absorption lines in the 2.2 μm spectral region. For this, we obtained a series of high-resolution, high S/N spectra of 99.99% 12C-enriched samples of pure methane and its dilute mixtures in dry air at cold temperatures down to 150 K using the Bruker IFS 125HR Fourier transform spectrometer at JPL. The coolable absorption cell had an optical path of 20.38 cm and was specially built to reside inside the sample compartment of the Bruker FTS. The 13 spectra used in the analysis consisted of seven pure 12CH_4 spectra at pressures from 4.5 to 169 Torr and six air-broadened spectra with total sample pressures of 113-300 Torr and methane volume mixing ratios between 4 and 9.7%. These 13 spectra were fit simultaneously using the multispectrum least-squares fitting technique. The results will be compared to existing values reported in the literature. K. Sung, A. W. Mantz, L. R. Brown, et al., J. Mol. Spectrosc., 162 (2010) 124-134. D. C. Benner, C. P. Rinsland, V. Malathy Devi, M. A. H. Smith and D. Atkins, JQSRT, 53 (1995) 705-721. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  3. Plasma density characterization at SPARC_LAB through Stark broadening of Hydrogen spectral lines

    Science.gov (United States)

    Filippi, F.; Anania, M. P.; Bellaveglia, M.; Biagioni, A.; Chiadroni, E.; Cianchi, A.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Mostacci, A.; Palumbo, L.; Pompili, R.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Zigler, A.

    2016-09-01

    Plasma-based acceleration techniques are of great interest for future, compact accelerators due to their high accelerating gradient. Both particle-driven and laser-driven Plasma Wakefield Acceleration experiments are foreseen at the SPARC_LAB Test Facility (INFN National Laboratories of Frascati, Italy), with the aim to accelerate high-brightness electron beams. In order to optimize the efficiency of the acceleration in the plasma and preserve the quality of the accelerated beam, the knowledge of the plasma electron density is mandatory. The Stark broadening of the Hydrogen spectral lines is one of the candidates used to characterize plasma density. The implementation of this diagnostic for plasma-based experiments at SPARC_LAB is presented.

  4. Breakdown of the line-space concept in Stark broadening of spectral lines by plasmas

    International Nuclear Information System (INIS)

    A study is presented that proves that the standard model for calculation of line shapes, e.g., transitions from nl to n'l' must be modified to include levels from higher principal quantum number manifolds, ndouble-prime>n'. This becomes particularly important in the study of transitions without central components, exhibiting a central minimum, as the effect of the higher ndouble-prime states is to cause a filling in of the central minimum. An analytic derivation is provided and detailed calculations are performed to illustrate the effect. copyright 1998 The American Physical Society

  5. [Determination of relative error of pressure-broadening linewidth for the experimentally indistinguishable overlapped spectral lines with Voigt profile].

    Science.gov (United States)

    Lin, Jie-Li; Huang, Yi-Qing; Lu, Hong

    2005-01-01

    The simulation and fitting of the overlapped spectral lines with Voigt profile were presented in this paper. The relative errors epsilon of the fitted pressure-broadening linewidth when taking the overlapped spectral line as one spectrum were discussed in detail. The relationship between such error and the two spectral lines center distance deltav0, and theoretical pressure-broadening linewidth deltav(L)0 were analyzed. Epsilon is found to be very large and the relationship between epsilon and deltav0, deltav(L)0 is very complicated when the value of pressure-broadening linewidth is considerably less than that of Dopplerian one deltavD. When deltav(L)0 is comparative to deltaVD the relationship between epsilon and deltav0 is close to the smooth two-order polynomial curve. However, the slop of this curve is negative while deltav(L)0 is smaller than deltavD and is positive when larger. Generally, epsilon decreases with the increase of proportion of deltav(l)0 to the whole spectral linewidth. All the above conclusion and corresponding data are the significant reference to determine the precise pressure-broadening coefficient from the experimentally indistinguishable overlapped spectrum, as well as to correct the fitted pressure-broadening linewidth. PMID:15852837

  6. Role of Lorentz–Stark broadening of hydrogen spectral lines in magnetized plasmas: Applications to magnetic fusion and solar physics

    International Nuclear Information System (INIS)

    Broadening of hydrogen spectral lines in plasmas is an important diagnostic tool for many applications (here and below by “hydrogen atoms” and “hydrogen spectral lines” we mean atoms and spectral lines of hydrogen, deuterium, and tritium). In magnetized plasmas radiating hydrogen atoms moving with the velocity v across the magnetic field B experience a Lorentz electric field EL=v×B/c in addition to other electric fields. Since the velocity v has a distribution, so does the Lorentz field, thus making an additional contribution to the broadening of spectral lines. Compared to previous studies of this contribution, we cover the following new aspects. First, we consider the Lorentz–Doppler broadening of highly-excited hydrogen lines and produce new analytical results for arbitrary strength of the magnetic field B. We show for the first time that in the high-B case, the π-components of hydrogen lines are significantly suppressed compared to the σ-components. Second, we derive analytically Lorentz-broadened profiles of highly-excited hydrogen lines. We obtain expressions for the principal quantum number nmax of the last observable hydrogen line in the spectral series. These expressions differ very significantly from the corresponding Inglis–Teller result and constitute a new diagnostic method allowing to measure the product T1/2B, where T is the atomic temperature. Third, we consider magnetized plasmas containing a low-frequency electrostatic turbulence. This kind of turbulence causes anomalous transport phenomena (e.g., the anomalous resistivity) and is therefore very important to be diagnosed. We derive analytically distributions of the total electric field and the corresponding Stark profiles of hydrogen lines. We demonstrate that our findings lead to a significantly revised interpretation of the previous and future experimental data in magnetic fusion and the observational data in solar physics. - Highlights: • New analytical results for the Lorentz

  7. Line broadening caused by Coulomb carrier-carrier correlations and dynamics of carrier capture and emission in quantum dots

    DEFF Research Database (Denmark)

    Uskov, Alexander V; Magnúsdóttir, Ingibjörg; Tromborg, Bjarne;

    2001-01-01

    Mechanisms of pure dephasing in quantum dots due to Coulomb correlations and the dynamics of carrier capture and emission are suggested, and a phenomenological model for the dephasing is developed. It is shown that, if the rates of these capture and emission processes are sufficiently high, signi......, significant homogeneous line broadening of the order of several meV can result....

  8. Role of Lorentz-Stark broadening of hydrogen spectral lines in magnetized plasmas: Applications to magnetic fusion and solar physics

    Science.gov (United States)

    Oks, Eugene

    2015-05-01

    Broadening of hydrogen spectral lines in plasmas is an important diagnostic tool for many applications (here and below by "hydrogen atoms" and "hydrogen spectral lines" we mean atoms and spectral lines of hydrogen, deuterium, and tritium). In magnetized plasmas radiating hydrogen atoms moving with the velocity v across the magnetic field B experience a Lorentz electric field EL=v×B/c in addition to other electric fields. Since the velocity v has a distribution, so does the Lorentz field, thus making an additional contribution to the broadening of spectral lines. Compared to previous studies of this contribution, we cover the following new aspects. First, we consider the Lorentz-Doppler broadening of highly-excited hydrogen lines and produce new analytical results for arbitrary strength of the magnetic field B. We show for the first time that in the high-B case, the π-components of hydrogen lines are significantly suppressed compared to the σ-components. Second, we derive analytically Lorentz-broadened profiles of highly-excited hydrogen lines. We obtain expressions for the principal quantum number nmax of the last observable hydrogen line in the spectral series. These expressions differ very significantly from the corresponding Inglis-Teller result and constitute a new diagnostic method allowing to measure the product T1/2B, where T is the atomic temperature. Third, we consider magnetized plasmas containing a low-frequency electrostatic turbulence. This kind of turbulence causes anomalous transport phenomena (e.g., the anomalous resistivity) and is therefore very important to be diagnosed. We derive analytically distributions of the total electric field and the corresponding Stark profiles of hydrogen lines. We demonstrate that our findings lead to a significantly revised interpretation of the previous and future experimental data in magnetic fusion and the observational data in solar physics.

  9. Broadening of the sodium 568.8, 589, 615.4 and 819.4 nm lines by atomic hydrogen

    International Nuclear Information System (INIS)

    Linewidths and shifts have been calculated in the impact approximation for atomic hydrogen broadening of the Na resonance and 3d-3p, 4d-3p and 5s-3p lines. The S-matrix elements required have been calculated in a time-dependent close-coupling approximation with straight-line paths for each Na term, including fine structure. The NaH potentials were determined using ab initio methods. Allowance was made for possible distant non-adiabatic transitions associated with ionic-covalent avoided crossings in 1Σ+ symmetry. Our result for the width of the resonance line at 5000 K is somewhat below the observed value, although the calculated shift coefficient is consistent with experiment. The shift coefficient for the 615.4 nm (5s-3p) lines is found to be comparable with the broadening coefficient, primarily due to unusual behaviour in the long-range 5s Σ+ potentials. The 819.4 nm (3d-3p) lines are found to have a larger broadening coefficient than the 568.8 nm (4d-3p) lines. For all the multiplets considered the different components of each line have widths differing by no more than a few per cent. Simple empirical fits are provided to the width coefficients of each multiplet. (author)

  10. Observations of Relativistically Broadened Iron Kalpha Lines From Stellar Mass Black Holes

    Science.gov (United States)

    Tomsick, John

    2016-04-01

    The measurement of Doppler broadened and gravitationally redshifted iron emission lines from accreting black holes has been used to measure the inner radius of the optically thick disk (Rin). At high mass accretion rates, when the disk is at or close to the Innermost Stable Circular Orbit (ISCO), a determination of Rin provides a constraint on the spin of the black hole. Measuring Rin can also provide information about whether the disk is truncated or not, and this is especially important for understanding the relationship between the disk and the steady jet in the hard state. Over the past few years, the Nuclear Spectroscopic Telescope Array (NuSTAR) has provided improved measurements due to its combination of bandpass (3-79 keV), good energy resolution, and high throughput. In this presentation, we discuss NuSTAR results for a number of stellar mass black holes (e.g., Cyg X-1, GX 339-4, and GRS 1739-278). While these observations have been successful in obtaining measurements of Rin, the improved spectra have also provided extra information about the source geometry and the inner disk inclination, which we will discuss.

  11. A comparative study of the broadening effect on rotational lines by methane and noble gases

    International Nuclear Information System (INIS)

    Line broadening measurements for the mixtures HCl-CH4 and HCl-CD4 have been performed and the results of these experiments are reported. Current theoretical models for the systems studied are briefly discussed. In order to identify specific effects the authors have tried to find a generalisation for linewidth cross-sections for the HCl-noble gas systems. This is done in the spirit of the well known corresponding state treatment in statistical mechanics in an attempt to find, in terms of reduced variables, a generalised intermolecular potential for these systems. Extensive calculations on the HCl-Ar and HCl-Kr intermolecular potentials, as derived from linewidth measurements, are reported in an attempt to extract a more exact potential for these systems. The results are compared with other recent results from the literature. The use of a semi-empirical method for the evaluation of the experimental data is described. This empirical method has been used in a comparison between the HCl-noble gas experiments and the present experiments of HCl-methane. The possibility of splitting the observed data into a 'noble gas' part and a 'extra' part due to the intermolecular interactions which result from the coupling of the HCl rotations with the internal degrees of freedom of the methane molecules is discussed. (Auth.)

  12. Coherent population trapping resonances at lower atomic levels of Doppler broadened optical lines

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, E; Hamid, R; Çelik, M [National Metrology Institute of Turkey, Gebze, Kocaeli (Turkey); Özen, G [Istanbul Technical University, Faculty of Science and Letters, Engineering Physics Department Maslak, Istanbul (Turkey); Izmailov, A Ch [Institute of Physics, Azerbaijan National Academy of Sciences, H. Javid av. 33, Baku, Az-1143 (Azerbaijan)

    2014-11-30

    We have detected and analysed narrow high-contrast coherent population trapping (CPT) resonances, which are induced in absorption of a weak monochromatic probe light beam by counterpropagating two-frequency pump radiation in a cell with rarefied caesium vapour. The experimental investigations have been performed by the example of nonclosed three level Λ-systems formed by spectral components of the D{sub 2} line of caesium atoms. The applied method allows one to analyse features of the CPT phenomenon directly at a given low long-lived level of the selected Λ-system even in sufficiently complicated spectra of atomic gases with large Doppler broadening. We have established that CPT resonances in transmission of the probe beam exhibit not only a higher contrast but also a much lesser width in comparison with well- known CPT resonances in transmission of the corresponding two-frequency pump radiation. The results obtained can be used in selective photophysics, photochemistry and ultra-high resolution atomic (molecular) spectroscopy. (laser applications and other topics in quantum electronics)

  13. MODIFICATION OF THE MOOG SPECTRAL SYNTHESIS CODES TO ACCOUNT FOR ZEEMAN BROADENING OF SPECTRAL LINES

    International Nuclear Information System (INIS)

    In an attempt to widen access to the study of magnetic fields in stellar astronomy, I present MOOGStokes, a version of the MOOG one-dimensional local thermodynamic equilibrium radiative transfer code, overhauled to incorporate a Stokes vector treatment of polarized radiation through a magnetic medium. MOOGStokes is a suite of three complementary programs, which together can synthesize the disk-averaged emergent spectrum of a star with a magnetic field. The first element (a pre-processing script called CounterPoint) calculates for a given magnetic field strength, wavelength shifts, and polarizations for the components of Zeeman-sensitive lines. The second element (a MOOG driver called SynStokes derived from the existing MOOG driver Synth) uses the list of Zeeman-shifted absorption lines together with the existing machinery of MOOG to synthesize the emergent spectrum at numerous locations across the stellar disk, accounting for stellar and magnetic field geometry. The third and final element (a post-processing script called DiskoBall) calculates the disk-averaged spectrum by weighting the individual emergent spectra by limb darkening and projected area, and applying the effects of Doppler broadening. All together, the MOOGStokes package allows users to synthesize emergent spectra of stars with magnetic fields in a familiar computational framework. MOOGStokes produces disk-averaged spectra for all Stokes vectors ( I, Q, U, V ), normalized by the continuum. MOOGStokes agrees well with the predictions of INVERS10 a polarized radiative transfer code with a long history of use in the study of stellar magnetic fields. In the non-magnetic limit, MOOGStokes also agrees with the predictions of the scalar version of MOOG

  14. Theoretical Calculations of Thermal Broadenings and Transition Probabilities of R, R' and B Line-Groups for Ruby

    Institute of Scientific and Technical Information of China (English)

    MA Dong-Ping; LIU Yan-Yun; CHEN Ju-Rong

    2001-01-01

    On the basis of the unified calculation of the thermal shifts of R1 line, R2 line and ground-state-splitting transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings of R,The theoretically predicted transition probabilities are in good agreement with the experimental ones.PACS numbers: 71.70.Ch, 78.20.Nv, 63.20.Mt, 63.20.Kr

  15. Stark broadening of B IV lines for astrophysical and laboratory plasma research

    CERN Document Server

    Dimitrijević, Milan S; Simić, Zoran; Kovačević, Andjelka; Sahal-Bréchot, Sylvie

    2013-01-01

    Stark broadening parameters for 36 multiplets of B IV have been calculated using the semi-classical perturbation formalism. Obtained results have been used to investigate the regularities within spectral series and temperature dependence.

  16. Determination of ion temperature distributions from Doppler broadenings of impurity lines in the vacuum UV region for tokamak discharges

    International Nuclear Information System (INIS)

    Doppler broadenings of impurity (O, N and C) lines in hydrogen discharges were observed with the JFT-2 and DIVA tokamak devices for the purpose of determining the spatial distribution of the ion temperature. A 1-meter Czerny-Turner type vacuum monochromator was used in higher orders for sufficient resolution. Impurity emissions are localized in shell-like regions in the minor cross-section. The radial distribution of the ion temperature was determined from the Doppler broadening of various impurity lines and from the localization of line intensities. The Doppler temperatures of the 0+6 ion were found to be 256 eV for a 100 kA, 14 kG discharge with JFT-2 and 220 eV for a 28 KA, 20 kG discharge with DIVA. (author)

  17. Exact trajectory in semiclassical line broadening and line shifting calculation test for H2-He Q(1) line

    International Nuclear Information System (INIS)

    The semiclassical model RB (Robert, D. and Bonamy, J. (Journal de Physique (Paris), 1979, 40, 923 for calculation of line width and line shift has been used in many applications. It contains an approximate 'parabolic' trajectory. Bykov, A.D. et al, Atmospheric and Oceanic Optics (1992) 5, 587, have recently proposed an analytical expression for an exact treatment of the classical path. This paper analyses the consequence of introducing the exact trajectory within the RB model for the H2-He Q(1) line chosen as a simple test. Moreover, a comparison with results of exact close-coupling calculations is also given for this molecular system. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. A spectrometer for the measurement of the Doppler broadening of the annihilation line with efficient reduction of background

    International Nuclear Information System (INIS)

    Following Lynn and the suggestion made by MacKenzie we describe a Doppler broadening (DB) spectrometer with efficient reduction of the background (BG). The simple experimental set-up achieved a peak to the BG ratio for the annihilation line of the order 1000:1. In this work, attention is given to the problem of the BG correction under the annihilation line, which has not been described in the literature. Measurements of Doppler profile of the annihilation line in Ni, Cu and a single crystal of Si are presented as an illustration of the advantage of the applications of the suggested BG reduction and correction technique. (orig.)

  19. Line-shape study of self-broadened O2 transitions measured by Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectroscopy

    International Nuclear Information System (INIS)

    We present high-sensitivity and high-spectral-resolution line-shape and line-intensity measurements of self-broadened O2 b 1Σg+(v=1)(leftarrow)X 3Σg-(v=0) band transitions measured using the Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectroscopy technique. We give collisional broadening parameters and take into account the line-narrowing effects described by Dicke narrowing or the speed dependence of collisional broadening. We compare line intensities measured with relative uncertainties below 0.4% to data available in the HITRAN spectroscopic database.

  20. Broadening of CO2 lines in the 4.3 μm region by H2O

    Science.gov (United States)

    Delahaye, T.; Landsheere, X.; Pangui, E.; Huet, F.; Hartmann, J.-M.; Tran, H.

    2016-08-01

    Transmission spectra of CO2 highly diluted in water vapor have been recorded at 50 and 95 °C for four pressures between 0.02 and 0.1 atm using a high resolution Fourier Transform spectrometer. The collisional (Lorentz) widths of many lines of the ν3 band (and of some of the ν3 + ν2 - ν2 hot band) have been retrieved from each spectrum through fits using Voigt line shapes. Our result are about 4% lower than the values recommended in a previous study but they confirm the relative variations of the line broadening on the rotational quantum numbers. We also provide the first determination of H2O-induced line shifts of CO2 lines.

  1. Air pressure broadening and shifting of high-J lines of (00011) 12C16O2

    International Nuclear Information System (INIS)

    The absorption spectra of carbon dioxide (isotope 626, natural abundance in air, ambient temperature) have been studied at total pressures 68-570 Torr with spectral resolution 0.003-0.005 cm-1. The spectra were measured in the spectral domain of 2273-2393 cm-1 by FTIR spectrometer Bruker IFS 125 HR equipped with White-type multipass cell (6.4-41.6 m) and with a cell having 10 cm optical path length. Pressure broadening and shift coefficients were obtained from a series of spectra by means of a nonlinear least-squares spectral fitting technique for the lines of the (00011) <- (00001) band with rotational quantum number up to J=82. For fitting of the individual line shapes, we used the Voigt profile with pre-calculated Doppler broadening parameter. The experimental pressure broadening and shift coefficients are compared with the values available in spectroscopic databases HITRAN 2008 and Carbon Dioxide Spectroscopic Databank (CDSD-296) and with other experimental values reported in the literature.

  2. Broadening of the Spectral Atomic Lines Analysis in High Density Argon Corona Plasma by Using Voigt Profile

    Science.gov (United States)

    Nur, M.; Bonifaci, N.; Denat, A.; Atrazhev, V. M.

    2015-06-01

    Studies of spectrum emission from high density argon plasma corona has been done. The analysis of the boardening of spectral atomic lines of Ar-I profile has been curried out by using an empirical approximation based on a Voigt profile. Full-width at half-maximum (FWHM) of the spectral-lines of 763.5 nm has been determined from atmospheric pressure until liquid state. The study liquid argon was curried out in a variation of temperature from K to 151.2 K and hydrostatics pressure from 2.1 MPa to 6.4 MPa. These pressure gives the densities N∞ (i.e. density very far from ionization zone) a variation from 1.08 1022 to 2.11 1022 cm-3. FWHM of Voigt approximation (Wv) of the line 763,5 nm of 'Ar I for: the emission lamp very low pressure (Wv = 0,160 nm) and our corona discharge at a pressure of MPa (Wv = 0,67 nm) and at a pressure of 9,5 MPa (Wv = 1,16 nm). In gas, corona plasma has been generated from 0.1 MPa to 9.5 MPa. We found that the broadening spectral line increase by increasing densities both for. the spectral-lines of 763.5 nm and 696.5 nm. We concluded that broadening of spectrum cause of Van der Waals force.

  3. Pressure broadening measurement of submillimeter-wave lines of O3

    Science.gov (United States)

    Yamada, M. M.; Amano, T.

    2005-10-01

    The pressure broadening coefficients and their temperature dependences for two submillimeter-wave transitions of ozone, one being monitored with Odin and the other to be monitored with JEM/SMILES and EOS-MLS, have been determined by using a BWO based submillimeter-wave spectrometer. The measurements have also been extended to one of the symmetric isotopic species, 16O18O16O. The isotopic species is observed in natural abundance and as a consequence the temperature dependence is not determined due to weak signal intensity. The pressure broadening parameters are determined with better than 1% accuracy, while the temperature dependence exponents are obtained within 1.5 3% accuracy for the normal species transitions.

  4. Pressure broadening measurement of submillimeter-wave lines of O{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, M.M. [Institute for Astrophysics and Planetary Sciences, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512 (Japan); Amano, T. [Institute for Astrophysics and Planetary Sciences, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512 (Japan)]. E-mail: amano@mx.ibaraki.ac.jp

    2005-10-01

    The pressure broadening coefficients and their temperature dependences for two submillimeter-wave transitions of ozone, one being monitored with Odin and the other to be monitored with JEM/SMILES and EOS-MLS, have been determined by using a BWO based submillimeter-wave spectrometer. The measurements have also been extended to one of the symmetric isotopic species, {sup 16}O{sup 18}O{sup 16}O. The isotopic species is observed in natural abundance and as a consequence the temperature dependence is not determined due to weak signal intensity. The pressure broadening parameters are determined with better than 1% accuracy, while the temperature dependence exponents are obtained within 1.5-3% accuracy for the normal species transitions.

  5. Measurement of the ion temperature in Petula from the Doppler broadening of impurity lines

    International Nuclear Information System (INIS)

    The impurities temperature in PETULA has been obtained with a high resolution spectrometer from the Doppler broadening. A critical study of the precision of the measurements has been made and the influence of the decharge reproductibility has been shown. Moreover, the measured temperature does not agree necessarily with the temperature in the region where the impurity concentration is the highest. Some solutions to improve the measurement precision are proposed

  6. EUV Non-thermal Line Broadening and High-energy particles during Solar Flares

    CERN Document Server

    Kawate, Tomoko

    2013-01-01

    We have studied the relationship between the location of EUV nonthermal broadening and high-energy particles during the large flares by using EUV imaging spectrometer onboard {\\it Hinode}, Nobeyama Radio Polarimeter, Nobeyama Radioheliograph, and Atmospheric Imaging Assembly onboard {\\it Solar Dynamic Observatory}. We have analyzed the five large flare events which contain thermal rich, intermediate, and thermal poor flares classified by the definition discussed in the paper. We found that, in the case of thermal rich flares, the nonthermal broadening of \\ion{Fe}{24} occurred at the top of the flaring loop at the beginning of the flares. The source of the 17 GHz microwave is located at the footpoint of the flare loop. On the other hand, in the case of intermediate/thermal poor flares, the nonthermal broadening of \\ion{Fe}{24} occurred at the footpoint of the flare loop at the beginning of the flares. The source of the 17 GHz microwave is located at the top of the flaring loop. We discussed the difference betw...

  7. Stark broadening for diagnostics of the electron density in non-equilibrium plasma utilizing isotope hydrogen alpha lines

    International Nuclear Information System (INIS)

    Two Stark broadening parameters including FWHM (full width at half maximum) and FWHA (full width at half area) of isotope hydrogen alpha lines are simultaneously introduced to determine the electron density of a pulsed vacuum arc jet. To estimate the gas temperature, the rotational temperature of the C2 Swan system is fit to 2500 ± 100 K. A modified Boltzmann-plot method with bi-factor is introduced to determine the modified electron temperature. The comparison between results of atomic and ionic lines indicates the jet is in partial local thermodynamic equilibrium and the electron temperature is close to 13 000 ± 400 K. Based on the computational results of Gig-Card calculation, a simple and precise interpolation algorithm for the discrete-points tables can be constructed to obtain the traditional ne-Te diagnostic maps of two Stark broadening parameters. The results from FWHA formula by the direct use of FWHM = FWHA and these from the diagnostic map are different. It can be attributed to the imprecise FWHA formula form and the deviation between FWHM and FWHA. The variation of the reduced mass pair due to the non-equilibrium effect contributes to the difference of the results derived from two hydrogen isotope alpha lines. Based on the Stark broadening analysis in this work, a corrected method is set up to determine ne of (1.10 ± 0.08) × 1021 m−3, the reference reduced mass μ0 pair of (3.30 ± 0.82 and 1.65 ± 0.41), and the ion kinetic temperature of 7900 ± 1800 K

  8. Solving the line-shape problem with speed-dependent broadening and shifting and with Dicke narrowing. I. Formalism

    International Nuclear Information System (INIS)

    In this paper, we present a formalism for the exact calculation of spectral profile of an isolated line undergoing speed-dependent collisional broadening and shifting and Dicke narrowing. It is couched in the language of the density matrix as in the closely related fields of transport phenomena, laser physics, and nonlinear optics. The formalism is ab intio in spirit, permitting the calculation of the line shape starting only from a given interaction potential. The line shape is obtained by solving a transport/relaxation equation for the off-diagonal element of the density matrix, a macroscopic quantity. The collision operator in the transport/relaxation equation, which is determined from the (microscopic) interaction between the active molecule and the perturber, is presumed known

  9. Self- and Air-Broadened Line Shape Parameters of (12)CH(4) : 4500-4620 cm(-1)

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Sung, K.; Brown, L. R.; Crawford, T. J.; Smith, M. A. H.; Mantz, A. W.; Predoi-Cross, A.

    2014-06-01

    Accurate knowledge of spectral line shape parameters is important for infrared transmission and radiance calculations in the terrestrial atmosphere. We report the self and air-broadened Lorentz widths, shifts and line mixing coefficients along with their temperature dependencies for methane absorption lines in the 2.2 µm spectral region. For this, we obtained a series of high-resolution, high S/N spectra of 99.99% 12C-enriched samples of pure methane and its dilute mixtures in dry air at cold temperatures down to 150 K using the Bruker IFS 125HR Fourier transform spectrometer at JPL. The coolable absorption cell had an optical path of 20.38 cm and was specially built to reside inside the sample compartment of the Bruker FTS1. The 13 spectra used in the analysis consisted of seven pure 12CH4 spectra at pressures from 4.5 to 169 Torr and six air-broadened spectra with total sample pressures of 113-300 Torr and methane volume mixing ratios between 4 and 9.7%. These 13 spectra were fit simultaneously using the multispectrum least-squares fitting technique2. The results will be compared to existing values reported in the literature3. as part of the GNU EPrints system , and is freely redistributable under the GPL .

  10. A Monte Carlo estimate of crystallite-size and microstrain distribution functions from X-ray line broadening

    International Nuclear Information System (INIS)

    A method of X-ray line-broadening analysis is presented whereby the coherence length and microstrain contributions can be calculated using a Monte Carlo interference-function-fitting algorithm. The method is based on the 'column-like' crystal model and can be applied to both single and multiple-order reflections. Examples on simulated diffraction peaks, deformed face-centred-cubic palladium powder and heavily textured deformed body-centred-cubic low-carbon-steel sheets are presented and comparisons are made with currently applied methods. (orig.)

  11. Modelling dislocation-induced anisotropic line broadening in Rietveld refinements using a Voigt function. I. General Principles

    Energy Technology Data Exchange (ETDEWEB)

    Wu, E.; Gray, E.M.A. [Griffith Univ., Brisbane, QLD (Australia). School of Science; Kisi, E.H

    1998-06-01

    For pt.II see ibid., vol.31, p.363-8, 1998. The theory of dislocation-induced X-ray or neutron diffraction line broadening developed by Krivoglaz et al. and Wilkens has been adapted for Rietveld refinement of the powder diffraction profile by fitting a Voigt function to each peak. Information on both the type of slip system and the density of dislocations in the crystallites may then be found by evaluating the shape parameter and the index-dependent breadth of the Voigt function. (orig.) 31 refs.

  12. Atom Resonance Lines for Modeling Atmosphere: Studies of Pressure-Broadening of Alkali Atom Resonance Lines for Modeling Atmospheres of Extrasolar Giant Planets and Brown Dwarfs

    Science.gov (United States)

    Hasan, Hashima (Technical Monitor); Kirby, K.; Babb, J.; Yoshino, K.

    2005-01-01

    We report on progress made in a joint program of theoretical and experimental research to study the line-broadening of alkali atom resonance lines due to collisions with species such as helium and molecular hydrogen. Accurate knowledge of the line profiles of Na and K as a function of temperature and pressure will allow such lines to serve as valuable diagnostics of the atmospheres of brown dwarfs and extra-solar giant planets. A new experimental apparatus has been designed, built and tested over the past year, and we are poised to begin collecting data on the first system of interest, the potassium resonance lines perturbed by collisions with helium. On the theoretical front, calculations of line-broadening due to sodium collisions with helium are nearly complete, using accurate molecular potential energy curves and transition moments just recently computed for this system. In addition we have completed calculations of the three relevant potential energy curves and associated transition moments for K - He, using the MOLPRO quantum chemistry codes. Currently, calculations of the potential surfaces describing K-H2 are in progress.

  13. Numerical experiments on the broadening of emission lines formed in a disk

    International Nuclear Information System (INIS)

    The shapes of emission lines formed from a thin, narrow disk inclined to the plane of the sky are investigated. Where the ratio of the velocity of rotation v to the intrinsic line width sigma is greater than about 2.0, the profile may become double-peaked. Where v is comparable to or smaller than 2 sigma, the line is single-peaked. A solid disk always presents a single-peaked profile. Increasing the inclination of the disk to the line of sight increases the width of the line. The differing widths of the emission lines in stars of the same WN subtype may result from differing values of v, sigma, and the inclination of the disk to the plane of the sky. If the disk has a large hole in its middle, the intensity of the emission line is reduced from what it would be for a solid disk or for one with a small hole. 21 refs

  14. Photoluminescence fatigue and inhomogeneous line broadening in semi-insulating Tl6SeI4 single crystals

    International Nuclear Information System (INIS)

    Photoluminescence (PL) properties of semi-insulating Tl6SeI4 have been investigated. A broad emission band centered at 1.63 ± 0.02 eV was observed in all samples. The PL emission band is excitonic in nature and is tentatively attributed to a bound exciton emission. PL fatigue (a reduction in PL intensity under prolonged laser excitation) was always observed. The amount of PL fatigue depended on excitation power and temperature. PL fatigue kinetics are described by a stretched exponential with nominal lifetimes in the 10–265 s range. The recovery of the PL occurred within a few seconds of light cessation. The magnitude of PL fatigue in different samples correlated with inhomogeneous line broadening of the 1.63 eV emission band, such that broader bands exhibited more fatigue. An additional luminescence band centered at 1.78 eV was observed which increased in intensity under prolonged laser irradiation. The fatigue phenomenon is tentatively attributed to two mechanisms—the formation of photo-induced defects and the formation of quasi-stable particles. Both of these mechanisms introduce additional radiative and non-radiative recombination channels that lead to a decrease in the PL intensity under prolonged laser irradiation. Since inhomogeneous line broadening and PL fatigue are related to the concentration of defects or impurities, the measurement of these two parameters is an effective method to screen sample quality. (paper)

  15. Photoluminescence fatigue and inhomogeneous line broadening in semi-insulating Tl6SeI4 single crystals

    Science.gov (United States)

    Kostina, S. S.; Peters, J. A.; Lin, W.; Chen, P.; Liu, Z.; Wang, P. L.; Kanatzidis, M. G.; Wessels, B. W.

    2016-06-01

    Photoluminescence (PL) properties of semi-insulating Tl6SeI4 have been investigated. A broad emission band centered at 1.63 ± 0.02 eV was observed in all samples. The PL emission band is excitonic in nature and is tentatively attributed to a bound exciton emission. PL fatigue (a reduction in PL intensity under prolonged laser excitation) was always observed. The amount of PL fatigue depended on excitation power and temperature. PL fatigue kinetics are described by a stretched exponential with nominal lifetimes in the 10–265 s range. The recovery of the PL occurred within a few seconds of light cessation. The magnitude of PL fatigue in different samples correlated with inhomogeneous line broadening of the 1.63 eV emission band, such that broader bands exhibited more fatigue. An additional luminescence band centered at 1.78 eV was observed which increased in intensity under prolonged laser irradiation. The fatigue phenomenon is tentatively attributed to two mechanisms—the formation of photo-induced defects and the formation of quasi-stable particles. Both of these mechanisms introduce additional radiative and non-radiative recombination channels that lead to a decrease in the PL intensity under prolonged laser irradiation. Since inhomogeneous line broadening and PL fatigue are related to the concentration of defects or impurities, the measurement of these two parameters is an effective method to screen sample quality.

  16. Effect of thermal collective modes on the Stark broadening of hydrogen spectral lines in strongly coupled plasmas

    Science.gov (United States)

    Oks, E.

    2016-03-01

    The paper is motivated by the recent (2014) benchmark measurements of the full width at half maximum (FWHM) of the H α line by Kielkopf and Allard (KA), which reached the electron densities N e by two orders of magnitude greater than the corresponding previous benchmark experiments, namely up to N e = 1.4 × 1020 cm-3. At this range of N e, no theoretical calculations of the FWHM of the H α line existed, except calculations by KA; however, the latter is inconsistent because of the neglect of the contribution by plasma electrons. In the present paper we develop a consistent analytical theory that is relevant to the range of the electron densities reached in KA experiment. At this range of N e, a new factor becomes significant—the factor never taken into account in any previous simulations or analytical theories of the Stark broadening of hydrogen spectral lines: a rising contribution of the electrostatic plasma turbulence (EPT) at the thermal level of its energy density. We show that this contribution becomes comparable to the corresponding contribution by electron and ion microfields at this range of N e. As a result, our theoretical FWHM of the H α line becomes in a very good agreement with the experimental FWHM of the H α line by KA in the entire range of their electron densities. The present theory can be also used for calculating Stark profiles and the FWHM of other hydrogen spectral lines.

  17. The Nature of Line Broadening in Thermally Detected 57FeFe NMR

    International Nuclear Information System (INIS)

    57FeFe with isotopic concentrations from 15 to 95% is studied using NMR thermally detected by nuclear orientation. Lines are found to be consistently homogeneous. The contrast with previous inhomogeneous 57FeFe lines from Moessbauer detected NMR is explained by differences in radio frequency field strength.

  18. Stark broadening data for spectral lines of rare-earth elements: Nb III

    CERN Document Server

    Simić, Zoran; Popović, Luka Č

    2013-01-01

    The electron-impact widths for 15 doubly charged Nb ion lines have been theoretically determined by using the modified semiempirical method. Using the obtained results, we considered the influence of the electron-impact mechanism on line shapes in spectra of chemically peculiar stars and white dwarfs.

  19. Measured and Theoretical Self- and N(2)-Broadened Line Parameters in the ν6 Band of CH(3)D

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Sung, Keeyon; Predoi-Cross, Adriana; Smith, Mary Ann H.; Mantz, Arlan W.; Sinyakova, Tatyana; Buldyreva, Jeanna

    2014-06-01

    Monodeuterated 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 theν6 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

  20. Lifetime broadening of atomic lines produced upon ultrafast dissociation of HCl and HBr

    International Nuclear Information System (INIS)

    Highlights: • Ultrafast dissociation of HCl is triggered by 2p3/2 → σ* excitation. • Ultrafast dissociation of HBr is triggered by 3d5/2 → σ* excitation. • Photoelectron spectroscopy reveals sharp vibrational molecular lines and broad atomic lines. • The profiles of the atomic lines are analyzed in detail. • We extract the lifetime of the inner shell hole in the neutral atomic fragment. - Abstract: Ultrafast dissociation of the HCl and HBr molecules excited respectively to the 2p3/2 → σ* and 3d5/2 → σ* resonances are studied with high resolution photoelectron spectroscopy. Sharp vibrational molecular lines and broad atomic lines are observed. The analysis of the profile of the atomic lines gives access to the lifetimes of the inner shell 2p3/2 hole in the Cl* (2p3/2)−1 3s23p6 configuration, and the inner shell 3d5/2 hole in the Br* (3d5/2)−1 4s24p6 configuration

  1. Pressure broadening and shift of K D1 and D2 lines in the presence of 3He and 21Ne

    Science.gov (United States)

    Li, Rujie; Li, Yang; Jiang, Liwei; Quan, Wei; Ding, Ming; Fang, Jiancheng

    2016-06-01

    Due to the collisions with alkali-metal atoms, the buffer gases used in spin-exchange optical pumping systems induce a broadening of spectral profiles and a shift in the resonance frequency. Here we report the pressure broadening and shift rates of K D 1 and D 2 lines in the presence of 21Ne for the first time and values for 3He have been reinvestigated by means of laser absorption spectroscopy. We have also examined the temperature dependence of these collisional effects in a range of 435-458 K. A comparison for the broadening and shift rates to those of other isotopes, 4He and 20Ne, is presented.

  2. Another way to view the chain conformation broadening of the line-width distribution measured in dynamic light scattering

    Institute of Scientific and Technical Information of China (English)

    吴奇; 牛爱珍

    1999-01-01

    In dynamic laser light scattering (LLS), for a given polydisperse sample, a line-width distribution G(Γ) or the translational diffusion coefficient distribution G(D) can be obtained from the measured time correlation function. For rigid colloid particles, G(Γ) can be directly related to the hydrodynamic size distribution. However, for flexible polymer chains, G(Γ) depends not only on the chain length distribution, but also on the relaxation of the chain conformation; that is, even for a monodisperse polymer sample there still exists a chain conformation distribution. If the time scale of the chain conformation relaxation is comparable to that of the translational diffusion, such as in the case of a very long polymer chain, the conformation relaxation might lead to an additional broadening in G (Γ). This "conformation broadening" has been directly observed for the first time by comparing two G(Γ) s obtained from a poly(N-isopropyl-acrylamide) solution at~25℃ and~32℃ at which the solution is ther

  3. Statistics of relativistically broadened Fe K(alpha) lines in AGN

    Czech Academy of Sciences Publication Activity Database

    Guainazzi, M.; Bianchi, S.; Dovčiak, Michal

    2006-01-01

    Roč. 327, č. 10 (2006), s. 1032-1038. ISSN 0004-6337 Institutional research plan: CEZ:AV0Z10030501 Keywords : quasars * emission lines * nuclei ­ galaxi Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.399, year: 2006

  4. Analysis of line broadening and spectral asymmetry in an all-fiber torsional acousto-optic band-pass filter

    International Nuclear Information System (INIS)

    The transmission properties of an all-fiber torsional acousto-optic (AO) band-pass filter with a sub-nm bandwidth is studied. The device is based on torsional AO coupling in a highly birefringent (HB) optical fiber. The full width at half maximum (FWHM) measured in a conventional band (C-band) is 0.88 nm, which is compared with the theoretical value of 0.45 nm estimated by using the coupled mode theory. The line broadening and the spectral asymmetry observed in experiments are investigated in detail through our theoretical model and full numerical analyses. The influence of the non-uniformity in the birefringence of the HB fiber on the filter's transmission is analyzed quantitatively in terms of the change in the filtering bandwidth, the sidelobe asymmetry, and the resonance shift.

  5. Electron impact broadening of Si IV spectral lines: Comparison with recent experiments

    International Nuclear Information System (INIS)

    Electron impact widths of eight Si IV spectral lines have been calculated using our quantum mechanical method. Semiclassical perturbation calculations using atomic data from the SUPERSTRUCTURE code have been also performed. Comparison with recent measurements shows that they are always lower than our quantum mechanical, semiclassical perturbation and all other theoretical results. A disagreement in the importance of fine structure effects between our results and the measured ones has been reported here.

  6. How two-dimensional brick layer J-aggregates differ from linear ones: excitonic properties and line broadening mechanisms

    CERN Document Server

    Dijkstra, Arend G; Knoester, Jasper; Nelson, Keith A; Cao, Jianshu

    2016-01-01

    We study the excitonic coupling and homogeneous spectral line width of brick layer J-aggregate films. We begin by analysing the structural information revealed by the two-exciton states probed in two-dimensional spectra. Our first main result is that the relation between the excitonic couplings and the spectral shift in a two-dimensional structure is different (larger shift for the same nearest neighbour coupling) from that in a one-dimensional structure, which leads to an estimation of dipolar coupling in two-dimensional lattices. We next investigate the mechanisms of homogeneous broadening - population relaxation and pure dephasing - and evaluate their relative importance in linear and two-dimensional aggregates. Our second main result is that pure dephasing dominates the line width in two-dimensional systems up to a crossover temperature, which explains the linear temperature dependence of the homogeneous line width. This is directly related to the decreased density of states at the band edge when compared...

  7. Stress-strain relationship and XRD line broadening in [0001] textured hexagonal polycrystalline materials

    International Nuclear Information System (INIS)

    Stress analysis with X-ray diffraction (XRD) for hexagonal polycrystalline materials in the Laue classes 6/mmm and 6/m has been studied on the basis of the crystal symmetry of the constituent crystallites which was proposed by R. Yokoyama and J. Harada ['Re-evaluation of formulae for X-ray stress analysis in polycrystalline specimens with fibre texture', Journal of Applied Crystallography, Vol.42, pp.185-191 (2009)]. The relationship between the stress and strain observable by XRD in a hexagonal polycrystalline material with [0001] fibre texture was formulated in terms of the elastic compliance defined for its single crystal. As a result, it was shown that the average strains obtained in the crystallites for both symmetries of 6/mmm and 6/m are different from each other under the triaxial or biaxial stress field. Then, it turned out that the line width of XRD changes depending on the measurement direction. (author)

  8. Bayesian inference of nanoparticle-broadened x-ray line profiles

    CERN Document Server

    Armstrong, N; Cline, J P; Bonevich, J

    2003-01-01

    A single and self-contained method for determining the crystallite-size distribution and shape from experimental x-ray line profile data is presented. We have shown that the crystallite-size distribution can be determined without assuming a functional form for the size distribution, determining instead the size distribution with the least assumptions by applying the Bayesian/MaxEnt method. The Bayesian/MaxEnt method is tested using both simulated and experimental CeO$_{2}$ data. The results demonstrate that the proposed method can determine size distributions, while making the least number of assumptions. The comparison of the Bayesian/MaxEnt results from experimental CeO$_2$ with TEM results is favorable

  9. Spectral line broadening of decimeter and centimeter radio waves during radio communication through near-solar plasma with the Venera-15,16 space probes

    International Nuclear Information System (INIS)

    Results of data analysis on spectral line broadening of decimeter (λ=32 cm) and centimeter (λ=5 cm) radiosignals of the 'Venera-15,16' probes in the process of their propagation through near-solar plasma are presented. It is shown that the width of decimeter radiowave spectral line increases in case of single propagation of the radiowaves from 0.2 Hz, when the distance of beam line from the Sun is 30 solar radii R0, up to 600 Hz in case of the beam line removal by 2.5 R0. In case of double pass of the radiowaves the spectral line broadening increases 2.5-4-fold as compared with the case of single propagation. It is ascertained that frequency dependence of the spectral line width is dose to root-mean-square law for impact distances between 8 and 2.5 R0, and in certain cases it is much stronger

  10. DETERMINATION OF THE SPONTANEOUS EMISSION PROBABILITIES AND THE COLLISION SELF-BROADENING COEFFICIENTS OF THE СО2 SPECTRAL LINES

    Directory of Open Access Journals (Sweden)

    K. I. Arshinov

    2015-03-01

    Full Text Available The technique of simultaneous determination of the spontaneous emission probabilities Аmn and the collision self-broadening coefficients γmn of the СО2 spectral lines is presented. The dependence of the absorption coefficient on the gas pressure, obtained for the СО210R22 line at temperature 300 K was measured. Using the data, the spontaneous emission probability Аmn and the collision self-broadening coefficient γmn were calculated.

  11. Conversion efficiency and spectral broadening of the K-{alpha} line emitted from planar titanium targets irradiated with ultra-short laser pulses of high intensity

    Energy Technology Data Exchange (ETDEWEB)

    Arora, V.; Singhal, H.; Naik, P. A.; Gupta, P. D. [Laser Plasma Division, Raja Ramanna Centre for Advanced Technology, Indore 452 013 (India)

    2011-10-15

    A study of the conversion efficiency and line shape of the K-{alpha} x-ray line radiation from a planar titanium target irradiated by an ultra-short laser pulse is performed. The conversion efficiency and spectral broadening are studied as a function of laser intensity (5 x 10{sup 16}-10{sup 18} W cm{sup -2}), laser pulse duration (45 fs-800 fs), and laser fluence (2 x 10{sup 3}-4.2 x 10{sup 4} J cm{sup -2}). The K-{alpha}{sub 1} line (4510 eV) is observed to be broadened (up to {approx}9 eV), predominantly towards the higher energy side and strongly depends on the laser fluence rather than on laser intensity. The reason for the spectral broadening is attributed to K-{alpha} emission in warm dense plasma. The role of hot electrons and direct laser heating on spectral broadening is outlined. In addition to this, our observations indicates that the presence of pre-plasma strongly contribute to the observed broadening through the inner-shell transitions in multiply charged titanium ions in the pre-plasma. The appropriate laser irradiation parameters to achieve high conversion efficiency and minimum spectral width of the K-{alpha} radiation are identified. The study is important, since the control of the spectral profile is of general interest for diffraction or scattering experiments in view of its potential in increasing temporal resolution.

  12. Using the Doppler broadened γ line of the 10B(n,αγ)7Li reaction for thermal neutron detection

    Science.gov (United States)

    Ben-Galim, Y.; Wengrowicz, U.; Moreh, R.; Orion, I.; Raveh, A.

    2016-02-01

    When a thermal neutron is absorbed by 10B in the 10B(n,α)7Li reaction, there is a chance of 94% that a 478 keV photon be emitted by an excited 7Li nucleus. This reaction is exothermic with a Q-value of 2.31 MeV and the nuclei are emitted with kinetic energies of E(α)=1.47 MeV and E(7Li*)=0.84 MeV. This implies that the 478 keV γ line is emitted by a moving 7Li nucleus and hence is expected to be Doppler broadened. In the present work we suggest to use this broadening of the γ line as a fingerprint for the detection of thermal neutrons using a high resolution gamma spectrometer. We thus developed a Monte Carlo program using a MATLAB code based on a High Purity Germanium (HPGe) detector coupled with a Boron Carbide (B4C) sheet to calculate the γ line broadening. Our simulation shows that the FWHM width of the resulting γ line is 12.6 keV, in good agreement with our measurement. Hence the broadened γ line emitted by the 10B(n,αγ)7Li reaction and detected by a HPGe detector shows that this method is an effective tool for neutron detection while maintaining good gamma discrimination.

  13. Modeling of x-ray diffraction line broadening with the voigt function: Applications to high-(T[sub c]) superconductors. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Balzar, D.

    1993-01-01

    A method to analyze powder-diffraction line broadening is proposed and applied to some novel high-T(c) superconductors. Assuming that both size-broadened and strain-broadened profiles of the pure-specimen profile are described with a Voigt function, it is shown that the analysis of Fourier coefficients leads to the Warren-Averbach method of separation of size and strain contributions. The method was applied to two cubic structures with average volume-weighted domain sizes up to 3600 A, as well as to tetragonal and orthorhombic (La-Sr)2CuOr, which exhibit weak line broadenings and highly overlapping reflections. Comparison with the integral-breadth methods is given. Reliability of the method is discussed in the case of a cluster of the overlapping peaks. The analysis of La2CuO4 and La(1.85)M(0.15)CuO4 (M = Ca, Ba, Sr) high-T(c) superconductors showed that microstrains and incoherently diffracting domain sizes are highly anisotropic. In the superconductors, stacking-fault probability increases with increasing T(c); microstrain decreases. In La2CuO4, different broadening of (h00) and (0k0) reflections is not caused by stacking faults; it might arise from lower crystallographic symmetry.

  14. Method of averaged energy differences of coupled states and other approaches for calculation line broadening parameters of HD16O transitions

    Science.gov (United States)

    Dudaryonok, A. S.; Voronin, B. A.; Lavrentieva, N. N.; Lugovskoy, A. A.; Starikov, V. I.

    2012-11-01

    Air-broadening coefficients of the water isotopologue HD16O up to J = 50 for P, Q and R branches calculated using different methods are presented. For partially labeled lines ("good" quantum numbers: J, symmetry and level number) we combined three methods for calculating half-widths: J-dependence and JJ'-dependence up to J=15 and averaging coefficients calculated using a previously developed semi-empirical method for high J (15-50). For lines with full assignments based on normal modes v1, v2, v3, Ka, Kc we used: (a) an analytical model (approximation) which depends on use of rotational quantum numbers J and Ka for both the upper and lower levels; and (b) a method based on the estimate of the averaged energy differences between coupled states. The comparison of calculated data with broadening coefficients from HITRAN-2008 and available experimental data is presented. The resulting broadening coefficients can be used to calculate spectra of water vapor with hundreds millions of weak lines with reasonable accuracy. The line list VTT [Voronin, Tennyson, Tolchenov, MNRAS, 2010], supporting programs, files for calculations of spectra HD16O and estimation of broadening coefficient are made freely available also in electronic form via http://www.exomol.com.

  15. Spectral Line Parameters Including Temperature Dependences of Self- and Air-Broadening in the 2 (left arrow) 0 Band of CO at 2.3 micrometers

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Smith, M. A. H.; Mantz, A. W.; Sung, K.; Brown, L. R.; Predoi-Cross, A.

    2012-01-01

    Temperature dependences of pressure-broadened half-width and pressure-induced shift coefficients along with accurate positions and intensities have been determined for transitions in the 2spectral line parameters that consistently reproduce the spectrum of carbon monoxide over terrestrial atmospheric conditions.

  16. Line parameters including temperature dependences of self- and air-broadened line shapes of 12C16O2: 1.6-μm region

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Sung, Keeyoon; Brown, Linda R.; Crawford, Timothy J.; Miller, Charles E.; Drouin, Brian J.; Payne, Vivienne H.; Yu, Shanshan; Smith, Mary Ann H.; Mantz, Arlan W.; Gamache, Robert R.

    2016-07-01

    Pressure-broadened line shapes in the 30013←00001 (ν1+4 ν20 +ν3) band of 12C16O2 at 6228 cm-1 are reanalyzed using new spectra recorded with sample temperatures down to 170 K. High resolution, high signal-to-noise (S/N) laboratory measurements of line shapes (Lorentz air- and self-broadened half-width coefficients, pressure-shift coefficients and off-diagonal relaxation matrix element coefficients) as a function of gas sample temperatures for various pressures and volume mixing ratios are presented. The spectra were recorded using two different Fourier transform spectrometers (FTS): (1) the McMath-Pierce FTS located at the National Solar Observatory on Kitt Peak, Arizona (and reported in Devi et al., J Mol Spectrosc 2007;245:52-80) and, (2) the Bruker IFS-125HR FTS at the Jet Propulsion Laboratory in Pasadena, California. The 19 spectra taken at Kitt Peak were all recorded near room temperature while the 27 Bruker spectra were acquired both at room temperature and colder temperatures (170-296 K). Various spectral resolutions (0.004-0.011 cm-1), absorption path lengths (2.46-121 m) and CO2 samples (natural and 12C-enriched) were included in the dataset. To maximize the accuracies of the various retrieved line parameters, a multispectrum nonlinear least squares spectrum fitting software program was used to adjust the ro-vibrational constants (G,B,D etc.) and intensity parameters (including Herman-Wallis terms) instead of directly measuring the individual line positions and intensities. To minimize systematic residuals, line mixing (via off-diagonal relaxation matrix elements) and quadratic speed dependence parameters were included in the analysis. Contributions from other weakly absorbing bands: the 30013←00001 and 30012←00001 bands of 13C16O2, the 30013←00001 band of 12C16O18O, hot bands 31113←01101 and 32212←02201 of 12C16O2, as well as the 40013←10001 and the 40014←10002 bands of 12C16O2, present within the fitted interval were also measured

  17. Air- and self-broadened half widths, pressure-induced shifts, and line mixing in the ν2 band of 12CH4

    International Nuclear Information System (INIS)

    Lorentz self- and air-broadened half width and pressure-induced shift coefficients and their dependences on temperature have been measured from laboratory absorption spectra for nearly 130 transitions in the ν2 band of 12CH4. In addition line mixing coefficients (using the relaxation matrix element formalism) for both self- and air-broadening were experimentally determined for the first time for a small number of transitions in this band. Accurate line positions and absolute line intensities were also determined. These parameters were obtained by analyzing high-resolution (∼0.003 to 0.01 cm−1) laboratory spectra of high-purity natural CH4 and air-broadened CH4 recorded at temperatures between 226 and 297 K using the McMath–Pierce Fourier transform spectrometer (FTS) located at the National Solar Observatory on Kitt Peak, Arizona. A multispectrum nonlinear least squares technique was used to fit short (5–15 cm−1) spectral intervals in 24–29 spectra simultaneously. Parameters were determined for ν2 transitions up to J″=16. The variations of the measured broadening and shift parameters with the rotational quantum number index and tetrahedral symmetry species are examined. The present results are also compared with previous measurements available in the literature. -- Highlights: • Self- and air-broadening parameters of the methane ν2 band have been measured. • First determination of temperature dependences of line widths and shifts in this band. • First measurements of line mixing in the ν2 band. • Good agreement with similar parameters from previous studies

  18. Modelling dislocation-induced anisotropic line broadening in Rietveld refinements using a Voigt function. II. Application to neutron powder diffraction data

    Energy Technology Data Exchange (ETDEWEB)

    Wu, E.; Gray, E.M.A. [Griffith Univ., Nathan (Australia). Fac. of Sci. and Technol.; Kisi, E.H

    1998-06-01

    For pt.I see ibid., vol.31, p.356-62, 1998. In paper I an approach was developed to the problem of modelling dislocation-induced X-ray or neutron-diffraction-line broadening. This paper applies those findings to the Rietveld refinement of the neutron powder diffraction profiles of deuterium-cycled LaNi{sub 5} and {beta}-PdD{sub 0.66}. These interstitially modified materials exhibit, respectively, strong and weak anisotropic strain broadening. The broadening in LaNi{sub 5} is consistent with a dislocation slip system a/3 left angle anti 2110 right angle {l_brace}0 anti 110{r_brace}, in agreement with transmission electron microscopy studies. In PdD{sub 0.66} the model predicts a regular distribution of screw dislocations, which remains to be confirmed by other techniques. (orig.) 28 refs.

  19. Noble-gas broadening rates for the 6s2S0→6s6p 1,3P1 resonance and intercombination lines of barium

    International Nuclear Information System (INIS)

    The collisional-broadening and -shift rate coefficients (kbr and kshift), for both helium and argon buffer gases, have been measured in the impact limit for the 6s21S0→6s6p 3P1 intercombination transition of barium. Detailed absorption line shapes were measured at three different ground-state number densities by monitoring the transmitted intensity of a weak cw probe laser as it was scanned over the transition. A single, density-independent line shape was then constructed and fit to a sum of Voigt functions (to account for hyperfine structure and isotope shifts) in order to determine the broadening and shift rates. By repeating the process for several buffer-gas pressures, kbr and kshift were determined from least-squares straight-line fits to the broadening and shift rates versus buffer-gas number density. Absolute normalization of the line-shape data was used to provide accurate ground-state column densities. Column-density information was then combined with measurements of white-light-absorption equivalent widths for the 6s21S0→6s6p 1P1 resonance transition to yield broadening rates for that transition. These values for the resonance line lie between previous literature values, which are widely discrepant. Finally we measured the absolute metastable 6s5d 3D2 column density under conditions of optical pumping through the 3P1 level, and determined that, in steady state, even with a weak cw pump laser, ∼20% of all barium atoms in the vapor could be found in the 3D2 level (with approximately 60% spread over the full 3DJ metastable manifold)

  20. Broadening and shifting of the methanol 119 μm gain line of linear and circular polarization by collision with chiral molecules

    International Nuclear Information System (INIS)

    Evidence of circular dichroism has been observed in the spectral properties of a gas of left-right symmetric molecules. This dichroism comes about as the result of collisions of the symmetric molecules with left-right asymmetric molecules introduced as a buffer gas. In this sense, the dichroism can be said to have been transferred from the chiral buffer molecules to the symmetric, non-chiral molecules of the background vapor. This transferred dichroism appears as broadening in the gain line of the symmetric molecule which is asymmetric with respect to the right or left handedness of a circularly polarized probe. The broadening of the 119 μm line of the methanol molecule was observed using infrared-far infrared double resonance spectroscopy

  1. Determination of crystallite size and residual stress in MgO powder and in UO2 pellets from X-ray line broadening

    International Nuclear Information System (INIS)

    A new method for determining crystallite size and residual stress based on x-ray line broadening is decribed. Several magnesium oxide samples have been prepared from magnesium carbonate decompositions at 5000C, 6000C and 8000C, the average crystallite size of these samples lying between 6 and 23 nm. In uranium dioxide samples sintered in hydrogen atmosphere at 17000C/3h the average crystallite size as well as a microdeformation in the lattice have been determined. (Author)

  2. THE RELATIONSHIP BETWEEN EXTREME ULTRAVIOLET NON-THERMAL LINE BROADENING AND HIGH-ENERGY PARTICLES DURING SOLAR FLARES

    International Nuclear Information System (INIS)

    We have studied the relationship between the location of EUV non-thermal broadening and high-energy particles during large flares using the EUV Imaging Spectrometer on board Hinode, the Nobeyama Radio Polarimeter, the Nobeyama Radioheliograph, and the Atmospheric Imaging Assembly on board the Solar Dynamic Observatory. We have analyzed five large flare events that contain thermal-rich, intermediate, and thermal-poor flares classified by the definition discussed in the paper. We found that, in the case of thermal-rich flares, the non-thermal broadening of Fe XXIV occurred at the top of the flaring loop at the beginning of the flares. The source of 17 GHz microwaves is located at the footpoint of the flare loop. On the other hand, in the case of intermediate/thermal-poor flares, the non-thermal broadening of Fe XXIV occurred at the footpoint of the flare loop at the beginning of the flares. The source of 17 GHz microwaves is located at the top of the flaring loop. We discussed the difference between thermal-rich and intermediate/thermal-poor flares based on the spatial information of non-thermal broadening, which may provide clues that the presence of turbulence plays an important role in the pitch angle scattering of high-energy electrons

  3. Broadening of the R(0) and P(2) Lines in the 13CO Fundamental by Helium Atoms from 300 K down to 12 K: Measurements and Comparison with Close-Coupling Calculations

    Science.gov (United States)

    Thibault, F.; Mantz, A. W.; Claveau, C.; Valentin, A.; Hurtmans, D.

    2007-01-01

    We present measurements of He-broadening parameters for the R(0) and O(2) lines in the fundamental band of 13CO at different temperatures between 12K and room temperature. The broadening parameters are determined, taking into account confinement narrowing, by simultaneous least-squares fitting of spectra recorded using a frequency stabilized diode laser spectrometer. The pressure broadening cross sections are deduced and compared to close-coupling calculations and earlier results obtained for rotational transitions of 12 CO.

  4. Intensities and self-broadening coefficients of the strongest water vapour lines in the 2.7 and 6.25μm absorption bands

    OpenAIRE

    Ptashnik, Igor V.; McPheat, Robert; Polyansky, Oleg L.; Shine, Keith P.; Smith, Kevin M.

    2016-01-01

    Intensities and self-broadening coefficients are presented for about 460 of the strongest water vapour lines in the spectral regions 1400–1840 cm−1 and 3440–3970 cm−1 at room temperature, obtained from rather unique measurements using a 5-mm-path-length cell. The retrieved spectral line parameters are compared with those in the HITRAN database ver. 2008 and 2012 and with recent ab-initio calculations. Both the retrieved intensities and half-widths are on average in reasonable agreement with t...

  5. Alfv\\'en Wave Turbulence as a Coronal Heating Mechanism: Simultaneously Predicting the Heating Rate and the Wave-Induced Emission Line Broadening

    CERN Document Server

    Oran, R; van der Holst, B; Sokolov, I V; Gombosi, T I

    2014-01-01

    In the present work, we test the predictions of the AWSoM model, a global extended-MHD model capable of calculating the propagation and turbulent dissipation of Alfv\\'en waves in any magnetic topology, against high resolution spectra of the quiescent off-disk solar corona. Wave dissipation is the only heating mechanism assumed in this model. Combining 3D model results with the CHIANTI atomic database, we were able to create synthetic line-of-sight spectra which include the effects of emission line broadening due to both thermal and wave-related non-thermal motions. To the best of our knowledge this is the first time a global model is used to obtain synthetic non-thermal line broadening. We obtained a steady-state solution driven by a synoptic magnetogram and compared the synthetic spectra with SUMER observations of a quiescent area above the solar west limb extending between 1.04 and 1.34 solar radii at the equator. Both the predicted line widths and the total line fluxes were consistent with the observations...

  6. Measurement of Stark broadening parameters of Fe II and Ni II spectral lines by laser induced breakdown spectroscopy using fused glass samples

    International Nuclear Information System (INIS)

    The Stark widths of 36 Fe II and 27 Ni II spectral lines are measured by laser induced breakdown spectroscopy (LIBS). The use of fused glass samples prepared by borate fusion is evaluated for Stark broadening measurements in LIBS experiments. The spectra of laser-induced plasmas generated from fused glass samples containing oxides show improved line-to-background ratios compared to those measured with alloys. The diagnostics of the fused glass laser induced plasmas shows that their characteristic parameters are not very different from those of alloy plasmas. The electron density in the experiment is in the range (0.8–10)×1017 cm−3 and the temperature varies from 12000 K to 17600 K. These experimental Stark width data, most of which had not been measured previously, complete the data for Fe II and Ni II reported in earlier works, determined by LIBS using alloy samples. -- Highlights: • Measurements of Stark broadening parameters of 36 Fe II and 27 Ni II spectral lines. • Fused glass samples shown to be advantageous for Stark width measurements by LIBS. • Fused glass approach provides low homogeneous concentrations of studied element. • Line-to-background ratio is improved with respect to alloy samples. • Very low concentration is necessary for preventing self-absorption of strong lines

  7. Homogeneous and inhomogeneous broadenings and the Voigt line shapes in the phase-resolved and intensity sum-frequency generation vibrational spectroscopy

    Science.gov (United States)

    Chen, Shun-Li; Fu, Li; Gan, Wei; Wang, Hong-Fei

    2016-01-01

    In this report, we show that the ability to measure the sub-1 cm-1 resolution phase-resolved and intensity high-resolution broadband sum frequency generation vibrational spectra of the -CN stretch vibration of the Langmuir-Blodgett (LB) monolayer of the 4-n-octyl-4'-cyanobiphenyl (8CB) on the z-cut α-quartz surface allows the direct comparison and understanding of the homogeneous and inhomogeneous broadenings in the imaginary and intensity SFG vibrational spectral line shapes in detail. The difference of the full width at half maximum (FWHM) of the imaginary and intensity sum-frequency generation vibrational spectroscopy spectra of the same vibrational mode is the signature of the Voigt line shape and it measures the relative contribution to the overall line shape from the homogeneous and inhomogeneous broadenings in SFG vibrational spectra. From the phase-resolved and intensity spectra, we found that the FWHM of the 2238.00 ± 0.02 cm-1 peak in the phase-resolved imaginary and intensity spectra is 19.2 ± 0.2 cm-1 and 21.6 ± 0.4 cm-1, respectively, for the -CN group of the 8CB LB monolayer on the z-cut α-quartz crystal surface. The FWHM width difference of 2.4 cm-1 agrees quantitatively with a Voigt line shape with a homogeneous broadening half width of Γ = 5.29 ± 0.08 cm-1 and an inhomogeneous standard derivation width Δω = 5.42 ± 0.07 cm-1. These results shed new lights on the understanding and interpretation of the line shapes of both the phase-resolved and the intensity SFG vibrational spectra, as well as other incoherent and coherent spectroscopic techniques in general.

  8. Self-, N2-, O2-broadening coefficients and line parameters of HFC-32 for ν7 band and ground state transitions from infrared and microwave spectroscopy

    Science.gov (United States)

    Tasinato, Nicola; Turchetto, Arianna; Puzzarini, Cristina; Stoppa, Paolo; Pietropolli Charmet, Andrea; Giorgianni, Santi

    2014-09-01

    Hydrofluorocarbons have been used as replacement gases of chlorofluorocarbons, since the latter have been phased out by the Montreal Protocol due to their environmental hazardous ozone-depleting effects. This is also the case of difluoromethane (CH2F2, HFC-32), which nowadays is widely used in refrigerant mixtures together with CF3CH3, CF3CH2F, and CF3CHF2. Due to its commercial use, in the last years, the atmospheric concentration of HFC-32 has increased significantly. However, this molecule presents strong absorptions within the 8-12 μm atmospheric window, and hence it is a greenhouse gas which contributes to global warming. Although over the years several experimental and theoretical investigations dealt with the spectroscopic properties of CH2F2, up to now pressure broadening coefficients have never been determined. In the present work, the line-by-line parameters of CH2F2 are retrieved for either ground state or ν7 band transitions by means of microwave (MW) and infrared (IR) absorption spectroscopy, respectively. In particular, laboratory experiments are carried out on 9 pure rotational transitions of the ground state and 26 ro-vibrational transitions belonging to the ν7 band lying around 8.2 μm within the atmospheric region. Measurements are carried out at room temperature on self-perturbed CH2F2 as well as on CH2F2 perturbed by N2 and O2. The line shape analysis leads to the first determination of self-, N2-, O2-, and air-broadening coefficients, and also of line intensities (IR). Upon comparison, broadening coefficients of ground state transitions are larger than those of the ν7 band, and no clear dependence on the rotational quantum numbers can be reported. The obtained results represent basic information for the atmospheric modelling of this compound as well as for remote sensing applications.

  9. Intensities and self-broadening coefficients of the strongest water vapour lines in the 2.7 and 6.25 μm absorption bands

    Science.gov (United States)

    Ptashnik, Igor V.; McPheat, Robert; Polyansky, Oleg L.; Shine, Keith P.; Smith, Kevin M.

    2016-07-01

    Intensities and self-broadening coefficients are presented for about 460 of the strongest water vapour lines in the spectral regions 1400-1840 cm-1 and 3440-3970 cm-1 at room temperature, obtained from rather unique measurements using a 5-mm-path-length cell. The retrieved spectral line parameters are compared with those in the HITRAN database ver. 2008 and 2012 and with recent ab-initio calculations. Both the retrieved intensities and half-widths are on average in reasonable agreement with those in HITRAN-2012. Maximum systematic differences do not exceed 4% for intensities (1600 cm-1 band) and 7% for self-broadening coefficients (3600 cm-1 band). For many lines however significant disagreements were detected with the HITRAN-2012 data, exceeding the average uncertainty of the retrieval. In addition, water vapour line parameters for 5300 cm-1 (1.9 μm) band reported by us in 2005 were also compared with HITRAN-2012, and show average differences of 4-5% for both intensities and half-widths.

  10. Positron reactions with SF6 in hexane studied by measurements of the Doppler broadening of the annihilation line

    OpenAIRE

    Mogensen, O; Hirade, T.

    1993-01-01

    The Doppler broadening (DB) of annihilation radiation spectra were measured for solutions of SF6 in hexane at SF6 concentrations up to 1 M. By use of a new program GAUSSFIT the DB-spectra were analyzed in terms of a sum of the resolution-convoluted angular correlation spectrum for hexane and one or more extra, gaussians. Positron annihilation with electrons bound in fluorine gives an unusually broad DB-component. This effect was used to show that the positron reacts with SF6 in hexane with a ...

  11. Alkaline broadening in Stars

    CERN Document Server

    De Kertanguy, A

    2015-01-01

    Giving new insight for line broadening theory for atoms with more structure than hydrogen in most stars. Using symbolic software to build precise wave functions corrected for ds;dp quantum defects. The profiles obtained with that approach, have peculiar trends, narrower than hydrogen, all quantum defects used are taken from atomic database topbase. Illustration of stronger effects of ions and electrons on the alkaline profiles, than neutral-neutral collision mechanism. Keywords : Stars: fundamental parameters - Atomic processes - Line: profiles.

  12. Self- and air-broadened line shape parameters in the ν2+ν3 band of 12CH4: 4500-4630 cm-1

    Science.gov (United States)

    Devi, V. Malathy; Benner, D. Chris; Smith, Mary Ann H.; Mantz, Arlan W.; Sung, Keeyoon; Crawford, Timothy J.; Predoi-Cross, Adriana

    2015-02-01

    Accurate knowledge of spectral line shape parameters is important for infrared transmission and radiance calculations in the terrestrial atmosphere. In this paper, we report the self- and air-broadened Lorentz half-widths, pressure-induced shifts and line mixing coefficients (via off-diagonal relaxation matrix elements) along with their temperature dependences for methane ν2+ν3 absorption lines in the 4500-4630 cm-1 region of the Octad. For this, we recorded 14 high-resolution, high signal to noise ratio (S/N) spectra of high-purity (99.95% 12C-enriched) samples of pure methane and its dilute mixtures in dry air between 298 K and 148 K. A Bruker IFS 125HR Fourier transform spectrometer (FTS) at the Jet Propulsion Laboratory, Pasadena, California, was used to obtain the experimental data. The absorption cell used for this study was a specially built 20.38 cm long coolable cell installed in its sample compartment. The sample pressures for the pure 12CH4 spectra were 4.5-385 Torr; for the air-broadened spectra the total pressures ranged between 95 and 300 Torr with the methane volume mixing ratios between 0.04 and 0.097. All 14 spectra were fitted simultaneously using an interactive multispectrum nonlinear least-squares curve fitting technique. The results are compared to values reported in the literature.

  13. Broadening and shift of the intercombination spectral line of the second group elements (Hg, Cd and Zn) perturbed by inert gases

    International Nuclear Information System (INIS)

    The Van der Waals and Lennard - Jones potential parameters for the ground and exited states of the second group elements (Hg, Cd and Zn) perturbed by inert gases (Xe, Kr, Ar, Ne and He) have been calculated using coulomb approximation. The basis of the Lindholm -Foley impact theory and the calculated potential parameters are used for calculating the collision broadening and shift coefficients β and δ for the intercombination lines 253.7, 326.1 and 307.6 nm of Hg, Cd and Zn atoms respectively when they are colliding with inert gas atoms . The calculating coefficients of β and δ are compared with their corresponding experimental values, taken from literatures

  14. Stark Broadening and White Dwarfs

    CERN Document Server

    Dimitrijevic, Milan S; Simic, Zoran; Sahal-Brechot, Sylvie

    2012-01-01

    White dwarf and pre-white dwarf atmospheres are one of the best examples for the application of Stark broadening research results in astrophysics, due to plasma conditions very favorable for this line broadening mechanism. For example in hot hydrogen-deficient (pre-) white dwarf stars Teff = 75 000 K - 180 000 K and log g = 5.5-8 [cgs]. Even for much cooler DA and DB white dwarfs with typical effective temperatures of 10 000 K - 20 000 K, Stark broadening is usually the dominant broadening mechanism. In this review, Stark broadening in white dwarf spectra is considered and the attention is drawn to the STARK-B database (http://stark-b.obspm.fr/), containing Stark broadening parameters needed for white dwarf spectra analysis and synthesis, as well as to the new search facilities which will provide the collective effort to develop Virtual Atomic and Molecular Data Center (VAMDC - http://vamdc.org/).

  15. Solid-state proton NMR of paramagnetic metal complexes: DANTE spin echoes for selective excitation in inhomogeneously broadened lines

    Science.gov (United States)

    Carnevale, Diego; Perez Linde, A. J.; Bauer, Gerald; Bodenhausen, Geoffrey

    2013-08-01

    The paramagnetic complex bis(oxazolinylphenyl)amine-Fe(III)Cl2 is investigated by means of solid-state proton NMR at 18.8 T (800 MHz) using magic-angle spinning at 65 kHz. Spin echoes that are excited and refocused by combs of rotor-synchronized pulses in the manner of 'Delays Alternating with Nutation for Tailored Excitation' (DANTE) allow one to characterize different chemical environments that severely overlap in conventional MAS spectra. Such sequences combine two apparently contradictory features: an overall bandwidth exceeding several MHz, and very selective irradiation of a few kHz within inhomogeneously broadened sidebands. The experimental hyperfine interactions correlate well with DFT calculations.

  16. Experimental studies, line-shape analysis and semi-empirical calculations of broadening coefficients for CH335Cl–CO2 submillimeter transitions

    International Nuclear Information System (INIS)

    Rotational transitions in CH335Cl mixed with CO2 are recorded at 296 K and total pressures up to 0.6 Torr in the frequency interval 186–901 GHz (1.6–0.3 mm) for J=6→7, 10→11, 17→18, 22→23, 31→32, 33→34 and K=0–6, using the frequency-modulation spectrometer of the Laboratory PhLAM (Lille, France). These line-shapes are analyzed with the commonly used Voigt profile as well as with more refined Speed-Dependent Voigt and Galatry models accounting for the line narrowing induced, respectively, by the speed-dependence of the relaxation parameters and by velocity-changing collisions. Due to the high line intensities, the fitting procedure involves the full implementation of the Beer–Lambert law instead of its traditional linear approximation. The experimentally deduced J- and K-dependences of the pressure-broadening coefficients are further used to obtain the model parameters of a semi-empirical approach allowing massive calculations of line-shape parameters for enlarged ranges of rotational quantum numbers requested by spectroscopic databases. - Highlights: • Analysis of speed dependence of relaxation rates for CH3Cl–CO2 lines. • Determination of the model parameters for a semi-empirical theoretical approach. • Extensive calculations of line widths for large ranges of rotational quantum numbers

  17. Measurement of collision broadening of the P1(5) line of (0,0) band of OH A2Σ+ 2Π transition at high temperatures

    International Nuclear Information System (INIS)

    Even for the well-studied and ubiquitous species, OH, the current state of theoretical development of broadening theory does not allow extrapolation from low-temperature laboratory measurements to the range of practical combustion devices. We performed a series of experiments at typical combustion conditions to determine the collision broadening of the P1(5) line of the (0,0) band of OH A2Σ+ 2Π transition by Ar in shock-heated H2-O2-Ar mixtures and by air in H2-air flames over a wide range of stoichiometry (φ=0.01-10.0), temperature (T=780-2440 K), and pressure (p=0.7-10.0 atm). The values of the collision width, ΔνC, were acquired by fitting Voigt profiles to the measured spectral line shapes in flames and to the peak absorption coefficients (kν0) in shock tube experiments. Collision broadening parameters (2γAr, 2γN2, and 2γH2O) were then calculated assuming the linear dependence of ΔνC with pressure-the 2γN2 and 2γH2O values were inferred from 2γAir and the equilibrium concentration of N2 and H2O of a given flame. The temperature dependences of 2γi in our temperature range are, respectively, 1.0, 0.75, and 0.87 for Ar, N2, and H2O. The collision broadening cross sections (σ) deduced from 2γi values are expressed with an assumed form, σi(T)=σi,0(T0/T)k, T0=1000 K: for Ar, σAr,0=63.3 (A2), k=0.50; for N2, σN2,0=68.0 (A2), k=0.25; for H2O, σH2O,0=188.8 (A2), k=0.37

  18. Laser-induced line-narrowing effects in coupled Doppler-broadened transitions. II - Standing-wave features.

    Science.gov (United States)

    Feldman, B. J.; Feld, M. S.

    1972-01-01

    Previous theoretical results on the influence of a laser on the line shape of a coupled transition (laser-induced line narrowing) have been restricted to the case where the laser is detuned from the center of its atomic gain profile or is in the form of a traveling wave. The present paper extends these results to the case where the laser is an intense standing-wave field tunable to the center of its atomic gain profile (conditions for Lamb dip). A theoretical solution of the problem is developed, and a detailed discussion of line shapes and physical processes involved is included.

  19. The relaxation matrix for symmetric tops with inversion symmetry. I. Effects of line coupling on self-broadened ν1 and pure rotational bands of NH3.

    Science.gov (United States)

    Ma, Q; Boulet, C

    2016-06-14

    The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing effects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of self-broadened NH3. The half-widths and shifts in the ν1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated off-diagonal elements of the relaxation matrix and a comparison with the observed line mixing effects are reported in the companion paper (Paper II). PMID:27306003

  20. Quantum theory of spectral line shifts and broadening for hyperfine atomic transitions in a buffer gas medium

    International Nuclear Information System (INIS)

    The problem is solved of the formation of hyperfine transition spectral lines of active atoms in the atmosphere of an inert buffer gas. As a basis the quantum kinetic equation for the density matrix of the emitting atom is used. The following assumptions are made in deriving and solving the equation: smallness of the collision time compared with the time of free flight, small probability of reorientation of electron and nuclear spins in each collision and a large number of collisions during the emission period. It is found that the width and shape of the line significantly depend on the intensity of the weak magnetic field which induces Zeeman splitting of the hyperfine sublevels. In a zero magnetic field the line width is comparable to the line shift. With increase of the field intensity up to a certain value 10-2-10 Oe an appreciable decrease of the width occurs and it becomes smaller than the shift by several orders of magnitude. In this case the line shape is approximately Lorentzian. The shifts and widths due to the combined action of the Doppler effect and collisions are expressed in terms of the exact quantum-mechanical scattering amplitudes. Quasiclassical expressions for them and quantum corrections due to the nonclassical nature of translational motion of the atoms, which may reach 10% for light atoms, are found

  1. Experimental studies, line-shape analysis and semi-empirical calculations of broadening coefficients for CH335Cl-CO2 submillimeter transitions

    Science.gov (United States)

    Dudaryonok, A. S.; Lavrentieva, N. N.; Buldyreva, J.; Margulès, L.; Motiyenko, R. A.; Rohart, F.

    2014-09-01

    Rotational transitions in CH335Cl mixed with CO2 are recorded at 296 K and total pressures up to 0.6 Torr in the frequency interval 186-901 GHz (1.6-0.3 mm) for J=6→7, 10→11, 17→18, 22→23, 31→32, 33→34 and K=0-6, using the frequency-modulation spectrometer of the Laboratory PhLAM (Lille, France). These line-shapes are analyzed with the commonly used Voigt profile as well as with more refined Speed-Dependent Voigt and Galatry models accounting for the line narrowing induced, respectively, by the speed-dependence of the relaxation parameters and by velocity-changing collisions. Due to the high line intensities, the fitting procedure involves the full implementation of the Bee-Lambert law instead of its traditional linear approximation. The experimentally deduced J- and K-dependences of the pressure-broadening coefficients are further used to obtain the model parameters of a semi-empirical approach allowing massive calculations of line-shape parameters for enlarged ranges of rotational quantum numbers requested by spectroscopic databases.

  2. On the determination of plasma electron number density from Stark broadened hydrogen Balmer series lines in Laser-Induced Breakdown Spectroscopy experiments

    Energy Technology Data Exchange (ETDEWEB)

    Pardini, L., E-mail: loren.pard@gmail.com [Istituto di Chimica dei Composti Organometallici del CNR, Area della Ricerca del CNR di Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Legnaioli, S.; Lorenzetti, G.; Palleschi, V. [Istituto di Chimica dei Composti Organometallici del CNR, Area della Ricerca del CNR di Pisa, Via G. Moruzzi 1, 56124 Pisa (Italy); Gaudiuso, R.; De Giacomo, A. [Dipartimento di Chimica, Università di Bari, Via Orabona 4, 70126 Bari (Italy); Diaz Pace, D.M. [Instituto de Física ‘Arroyo Seco’, Facultad de Ciencias Exactas, Paraje Arroyo Seco, B7000GHG Tandil (Argentina); Anabitarte Garcia, F. [Photonic Engineering Group, Universidad de Cantabria, Edificio I+D+iTelecomunicación, Dpto. TEISA, 39005 Santander (Spain); Holanda Cavalcanti, G. de [Institute of Physics, Universidade Federal Fluminense, UFF, Campus da Praia Vermelha, Av. Gal Milton Tavares de Souza, Gragoatá, 24310 240 Niterói, RJ (Brazil); Parigger, C. [University of Tennessee Space Institute, 411 B. H. Goethert Parkway, Tullahoma, TN 37388-9700 (United States)

    2013-10-01

    In this work, different theories for the determination of the electron density in Laser-Induced Breakdown Spectroscopy (LIBS) utilizing the emission lines belonging to the hydrogen Balmer series have been investigated. The plasmas were generated by a Nd:Yag laser (1064 nm) pulsed irradiation of pure hydrogen gas at a pressure of 2 · 10{sup 4} Pa. H{sub α}, Η{sub β}, Η{sub γ}, Η{sub δ}, and H{sub ε} Balmer lines were recorded at different delay times after the laser pulse. The plasma electron density was evaluated through the measurement of the Stark broadenings and the experimental results were compared with the predictions of three theories (the Standard Theory as developed by Kepple and Griem, the Advanced Generalized Theory by Oks et al., and the method discussed by Gigosos et al.) that are commonly employed for plasma diagnostics and that describe LIBS plasmas at different levels of approximations. A simple formula for pure hydrogen plasma in thermal equilibrium was also proposed to infer plasma electron density using the H{sub α} line. The results obtained showed that at high hydrogen concentration, the H{sub α} line is affected by considerable self-absorption. In this case, it is preferable to use the H{sub β} line for a reliable calculation of the electron density. - Highlights: • We evaluated the electron density in LIPs utilizing the hydrogen Balmer series. • Plasmas were generated by a Nd:Yag laser (1064 nm) on pure hydrogen gas. • We show that at high hydrogen concentration, H{sub b}eta line is preferable than H{sub a}lpha. • We propose a formula to derive the plasma electron density using the H{sub a}lpha line.

  3. How two-dimensional brick layer J-aggregates differ from linear ones: Excitonic properties and line broadening mechanisms

    Science.gov (United States)

    Dijkstra, Arend G.; Duan, Hong-Guang; Knoester, Jasper; Nelson, Keith A.; Cao, Jianshu

    2016-04-01

    We study the excitonic coupling and homogeneous spectral line width of brick layer J-aggregate films. We begin by analysing the structural information revealed by the two-exciton states probed in two-dimensional spectra. Our first main result is that the relation between the excitonic couplings and the spectral shift in a two-dimensional structure is different (larger shift for the same nearest neighbour coupling) from that in a one-dimensional structure, which leads to an estimation of dipolar coupling in two-dimensional lattices. We next investigate the mechanisms of homogeneous broadening—population relaxation and pure dephasing—and evaluate their relative importance in linear and two-dimensional aggregates. Our second main result is that pure dephasing dominates the line width in two-dimensional systems up to a crossover temperature, which explains the linear temperature dependence of the homogeneous line width. This is directly related to the decreased density of states at the band edge when compared with linear aggregates, thus reducing the contribution of population relaxation to dephasing. Pump-probe experiments are suggested to directly measure the lifetime of the bright state and can therefore support the proposed model.

  4. Quantitative evaluation of the broadening of x-ray diffraction, Raman, and photoluminescence lines by dislocation-induced strain in heteroepitaxial GaN films

    International Nuclear Information System (INIS)

    Experimental x-ray diffraction, Raman, and photoluminescence line profiles from GaN films with different densities of threading dislocations are modeled using Monte Carlo calculations of the strain distribution due to these dislocations. We quantitatively analyze and compare the respective line broadenings predicted by these calculations for different dislocation densities. X-ray diffraction and Raman measurements reveal the strain in the whole volume of the film, due to the large penetration depth of the corresponding radiation, while photoluminescence measurements are sensitive to the strain close to the film surface, in a layer limited by the penetration depth of the radiation used for excitation. This difference in information depths becomes especially important for films in which the threading dislocation density is continuously decreasing during growth, as it can be achieved by vapor phase epitaxy methods. An additional narrowing of photoluminescence lines occurs due to two effects: first, the elastic relaxation of the dislocation strain at the free surface, and second, the suppression of luminescence from the most highly strained regions around the dislocation cores which act as centers of nonradiative recombination. (paper)

  5. Line broadening and crystallographic sites for Eu{sup 3+} in disordered double borate Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr

    2014-08-01

    Highlights: • The line broadening properties of Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4}: Eu{sup 3+} are investigated. • Three types of substitution sites for Eu{sup 3+} are identified in Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4}. • The crystal-field parameters are calculated from the {sup 7}F{sub J} levels. • The larger distribution of M-O distances gives higher crystal-field strength on Eu{sup 3+}. - Abstract: The samples of Eu{sup 3+}-doped Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} were synthesized by solid-state reaction. Line broadening and site-substitution properties of Eu{sup 3+} in Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} are investigated by the site-selective laser-excitation spectroscopy. Three excitation lines corresponding to the three crystallographic sites are observed in the excitation spectra of the {sup 7}F{sub 0} → {sup 5}D{sub 0} transition. The spectral lines in the excitation and emission spectra of Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4}:Eu{sup 3+} are much broader than those in usual crystalline lattices which are attributable to the structural disorder of the Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} lattice. Crystal-field splittings of three types of Eu{sup 3+} in Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4} are determined from selectively excited emission spectra. The crystal-field parameters and crystal-field strength parameters are calculated with the values of experimentally obtained {sup 5}D{sub 0} and {sup 7}F{sub J} energy levels. The results are discussed in relation with the distribution of the substitution sites for Eu{sup 3+} in Ca{sub 3}Gd{sub 2}(BO{sub 3}){sub 4}.

  6. Statistical removal of background signals from high-throughput 1H NMR line-broadening ligand-affinity screens

    International Nuclear Information System (INIS)

    NMR ligand-affinity screens are vital to drug discovery, are routinely used to screen fragment-based libraries, and used to verify chemical leads from high-throughput assays and virtual screens. NMR ligand-affinity screens are also a highly informative first step towards identifying functional epitopes of unknown proteins, as well as elucidating the biochemical functions of protein–ligand interaction at their binding interfaces. While simple one-dimensional 1H NMR experiments are capable of indicating binding through a change in ligand line shape, they are plagued by broad, ill-defined background signals from protein 1H resonances. We present an uncomplicated method for subtraction of protein background in high-throughput ligand-based affinity screens, and show that its performance is maximized when phase-scatter correction is applied prior to subtraction

  7. Statistical removal of background signals from high-throughput {sup 1}H NMR line-broadening ligand-affinity screens

    Energy Technology Data Exchange (ETDEWEB)

    Worley, Bradley; Sisco, Nicholas J.; Powers, Robert, E-mail: rpowers3@unl.edu [University of Nebraska-Lincoln, Department of Chemistry (United States)

    2015-09-15

    NMR ligand-affinity screens are vital to drug discovery, are routinely used to screen fragment-based libraries, and used to verify chemical leads from high-throughput assays and virtual screens. NMR ligand-affinity screens are also a highly informative first step towards identifying functional epitopes of unknown proteins, as well as elucidating the biochemical functions of protein–ligand interaction at their binding interfaces. While simple one-dimensional {sup 1}H NMR experiments are capable of indicating binding through a change in ligand line shape, they are plagued by broad, ill-defined background signals from protein {sup 1}H resonances. We present an uncomplicated method for subtraction of protein background in high-throughput ligand-based affinity screens, and show that its performance is maximized when phase-scatter correction is applied prior to subtraction.

  8. Determination of the plasma composition using blended stark-broadened emission lines in a self-magnetic pinch diode

    International Nuclear Information System (INIS)

    We analyzed visible spectra obtained in self-focusing, relativistic-electron diode experiments performed on the RITS-6 accelerator facility at Sandia National Laboratories (SNL). An electron beam emitted from the cathode strikes a planar anode surface with high current densities (∼1 MA/cm2), forming a plasma in the anode-cathode (A-K) gap. Radiation emitted from the plasma is imaged onto a spectrometer input slit via an optical fiber bundle. The spectrometer output is coupled to a gated, intensified charge-coupled device (ICCD) camera, yielding spatially resolved (2mm) spectra. The spectra from the high-density plasma region mainly exhibit emission that appears to be from a continuum source. However, the radiation intensity distribution cannot be explained by free-free or free-bound emissions. Rather, we suggest that the spectrum originates from the blending of many Stark-dominated spectral lines. Accordingly, the spectral intensity distribution provides information on the plasma composition and thermodynamic parameters. (author)

  9. High resolution Fourier transform spectroscopy of HD16O: Line positions, absolute intensities and self broadening coefficients in the 8800-11,600 cm-1 spectral region

    International Nuclear Information System (INIS)

    High-resolution water vapor absorption spectra have been measured at room temperature in the 8800-11,600 cm-1 spectral region. They were obtained using the mobile BRUKER IFS 120M Fourier transform spectrometer (FTS) from ULB-SCQP coupled to the 50 m base long multiple reflection White type cell in GSMA laboratory. The absorption path was 600 m and different H2O/HDO/D2O mixtures were used. Measurements of line positions, intensities and self-broadening coefficients were performed for the HD16O isotopologue. 6464 rovibrational assignment of the observed lines was made on the basis of global variational predictions and allowed the identification of new energy levels. 3ν3, 2ν1+ν3, 3ν1+ν2, ν1+2ν3 and 2ν2+2ν3 are the five strongest bands. The present paper provides a complementary data set on water vapor for atmospheric and astrophysical applications.

  10. Diagnostic of the self-healing of metallized polypropylene film by modeling of the broadening emission lines of aluminum emitted by plasma discharge

    International Nuclear Information System (INIS)

    Metallized-film capacitors have the property, even under high continuous voltage, to self-heal i.e., to clear a defect in the dielectric. The self-healing process is a consequence of a transient arc discharge. It has been previously shown that during the discharge, due to Joule effect, the metal is vaporized until the arc extinguishes. The discharge duration has been found to be inversely proportional to the mechanical pressure applied on the layers of metallized films making up a capacitor. The aim of this study is to understand the physical processes involved in this spontaneous extinction of the arc discharge. Emission spectroscopy has been used to provide information about the physical properties (temperatures, electronic and neutral particles densities, etc.) of the plasma induces by a self-healing. An analysis, based on the broadenings and shifts of Al atomic lines, of the experimental light spectra obtained has shown that the self-healing process leads to the generation, from the vaporized metal, of a high-density and relatively weakly ionized aluminum plasma. The plasma density increases with the pressure applied on the film layers and, consequently, the density power needed to extend the plasma zone increases as well and the arc discharge goes out faster as experimentally observed

  11. Rotational level-dependent collisional broadening and line shift of the A2Sigma(+)-X2Pi (1,0) band of OH in hydrogen-air combustion gases

    Science.gov (United States)

    Kessler, W. J.; Allen, M. G.; Davis, S. J.

    1993-01-01

    Measurements of the collisional broadening and line shift of the (1,0) band of the A2Sigma(+)-X2Pi system of OH are reported in atmospheric pressure hydrogen-air combustion gases. The measurements were made using a single-mode, narrow linewidth, frequency-doubled ring dye laser operating near 283 nm. The OH was generated in the combustion gases of a flat flame H2-air burner. Collisional broadening parameters for equilibrium mixtures of H2, O2, H2O, and N2 were obtained spanning a range of fuel/air equivalence ratios from 0.6 to 1.6 and temperatures from 1500 to 2050 K. Measurements were obtained spanning rotational quantum numbers from 4.5 to 16.5. The collision induced frequency shift was determined to be 0.1 that of the collisional broadening.

  12. H2, He, and CO2 line-broadening coefficients, pressure shifts and temperature-dependence exponents for the HITRAN database. Part 1: SO2, NH3, HF, HCl, OCS and C2H2

    Science.gov (United States)

    Wilzewski, Jonas S.; Gordon, Iouli E.; Kochanov, Roman V.; Hill, Christian; Rothman, Laurence S.

    2016-01-01

    To increase the potential for use of the HITRAN database in astronomy, experimental and theoretical line-broadening coefficients, line shifts and temperature-dependence exponents of molecules of planetary interest broadened by H2, He, and CO2 have been assembled from available peer-reviewed sources. The collected data were used to create semi-empirical models so that every HITRAN line of the studied molecules has corresponding parameters. Since H2 and He are major constituents in the atmospheres of gas giants, and CO2 predominates in atmospheres of some rocky planets with volcanic activity, these spectroscopic data are important for remote sensing studies of planetary atmospheres. In this paper we make the first step in assembling complete sets of these parameters, thereby creating datasets for SO2, NH3, HF, HCl, OCS and C2H2.

  13. Interpretation of magnetization transfer from inhomogeneously broadened lines (ihMT) in tissues as a dipolar order effect within motion restricted molecules

    Science.gov (United States)

    Varma, G.; Girard, O. M.; Prevost, V. H.; Grant, A. K.; Duhamel, G.; Alsop, D. C.

    2015-11-01

    Comparison of off-resonance saturation with single and dual frequency irradiation indicates a contribution of inhomogeneously broadened lines to magnetization transfer in tissues. This inhomogeneous magnetization transfer (ihMT) phenomenon can be exploited to produce images that highlight tissues containing myelin, in vivo. Here, a model for ihMT is described that includes dipolar order effects from magnetization associated with motion-restricted macromolecules. In this model, equal irradiation at positive and negative frequency offsets eliminates dipolar order and achieves greater saturation than irradiation at a single offset frequency using the same power. Fitting of mouse and human volunteer brain data at different irradiation powers and offset frequencies was performed to assess the relevance of the model and approximate tissue parameters. A key parameter in determining ihMT signal was found to be the relaxation time T1D associated with the dipolar order reservoir and the fraction f of the semi-solid, bound magnetization that possessed a nonzero T1D. Indeed, better fits of myelinated tissue were achieved when assuming f ≠ 1. From such fits, estimated T1Ds of mice in the white matter, (34 ± 14)ms, were much longer than in muscle, T1D = (1 ± 1)ms and the average f from white matter volunteer data was 2.2 times greater than that in grey matter. The combination of f and longer T1Ds was primarily responsible for the much higher ihMT in myelinated tissues, and provided explanation for the species variation. This dipolar order ihMT model should help guide future research, pulse sequence optimization, and clinical applications.

  14. Homogeneous and inhomogeneous broadenings and the Voigt line shapes in the phase-resolved and intensity sum-frequency generation vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shunli; Fu, Li; Gan, Wei; Wang, Hongfei

    2016-01-21

    In this report we show that the ability to measure the sub-1 cm-1 resolution phase-resolved and intensity high-resolution broadband sum frequency generation vibrational spectra (HR-BB-SFG-VS) of the –CN stretch vibration of the Langmuir-Blodgett (LB) monolayer of the 4-n-octyl-4’-cyanobiphenyl (8CB) on the z-cut α-quartz surface allows for the first time the direct comparison and understanding of the homogeneous and inhomogeneous broadenings in the imaginary and intensity SFG vibrational spectral lineshapes in detail. The difference of the full width at half maxima (FWHM) of the imaginary and intensity SFG-VS spectra of the same vibrational mode is the signature of the Voigt lineshape and it measures the relative contribution to the overall lineshape from the homogeneous and inhomogeneous broadenings in SFG vibrational spectra. From the phase-resolved and intensity spectra, we found that the FWHM of the 2238.00 ±0.02 cm-1 peak in the phase-resolved imaginary and intensity spectra is 19.2 ± 0.2 cm-1 and 21.6 ± 0.4 cm-1, respectively, for the –CN group of the 8CB LB monolayer on the z-cut α-quartz crystal surface. The FWHM width difference of 2.4 cm-1 agrees quantitatively with a Voigt lineshape with a homogeneous broadening half width of Γ = 5.29 ± 0.08 cm-1 and a inhomogeneous standard derivation width Δω = 5.42 ± 0.07 cm-1. These results shed new lights on the understanding and interpretation of the lineshapes of both the phase-resolved and the intensity SFG vibrational spectra, as well as other incoherent and coherent spectroscopic techniques in general.

  15. The Relaxation Matrix for Symmetric Tops with Inversion Symmetry. I. Effects of Line Coupling on Self-Broadened v (sub 1) and Pure Rotational Bands of NH3

    Science.gov (United States)

    Ma, Q.; Boulet, C.

    2016-01-01

    The Robert-Bonamy formalism has been commonly used to calculate half-widths and shifts of spectral lines for decades. This formalism is based on several approximations. Among them, two have not been fully addressed: the isolated line approximation and the neglect of coupling between the translational and internal motions. Recently, we have shown that the isolated line approximation is not necessary in developing semi-classical line shape theories. Based on this progress, we have been able to develop a new formalism that enables not only to reduce uncertainties on calculated half-widths and shifts, but also to model line mixing effects on spectra starting from the knowledge of the intermolecular potential. In our previous studies, the new formalism had been applied to linear and asymmetric-top molecules. In the present study, the method has been extended to symmetric-top molecules with inversion symmetry. As expected, the inversion splitting induces a complete failure of the isolated line approximation. We have calculated the complex relaxation matrices of selfbroadened NH3. The half-widths and shifts in the ?1 and the pure rotational bands are reported in the present paper. When compared with measurements, the calculated half-widths match the experimental data very well, since the inapplicable isolated line approximation has been removed. With respect to the shifts, only qualitative results are obtained and discussed. Calculated off-diagonal elements of the relaxation matrix and a comparison with the observed line mixing effects are reported in the companion paper (Paper II).

  16. Multispectrum measurements of spectral line parameters including temperature dependences of N2- and self-broadened half-width coefficients in the region of the ν9 band of 12C2H6

    International Nuclear Information System (INIS)

    Ethane is a prominent contributor to the spectrum of Titan, particularly in the ν9 region centered near 822 cm-1. To improve the spectroscopic line parameters at 12 μm, 41 high-resolution (0.0016-0.005 cm-1) absorption spectra of C2H6 were obtained at sample temperatures between 211 and 298 K with the Bruker IFS 120HR at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington. Two additional spectra were later recorded at ∼150 K using a new temperature-stabilized cryogenic cell designed for the sample compartment of the Bruker IFS 125HR at the Jet Propulsion Laboratory (JPL) in Pasadena, California. A multispectrum nonlinear least-squares fitting program was applied simultaneously to all 43 spectra to measure the line positions, intensities, N2- and self-broadened half-width coefficients and their temperature dependences. Reliable pressure-induced shift coefficients could not be obtained, however, because of the high congestion of spectral lines (due to torsional-split components, hot-band transitions as well as blends). Existing theoretical modeling of this very complicated ν9 region permitted effective control of the multispectrum fitting technique; some constraints were applied using predicted intensity ratios, doublet separations, half-width coefficients and their temperature dependence exponents in order to determine reliable parameters for each of the two torsional-split components. For 12C2H6, the resulting retrievals included 17 pQ and rQ sub-bands of ν9 (as well as some pP, rR sub-bands). Positions and intensities were measured for 3771 transitions, and a puzzling difference between previously measured ν9 intensities was clarified. In addition, line positions and intensities were obtained for two 12C2H6 hot bands (ν9+ν4-ν4, ν9+2ν4-2ν4) and the ν9 band of 13C12CH6, as well as several hundred presently unidentified transitions. N2- and self-broadened half-width coefficients were determined for over 1700 transitions, along with

  17. Comparison of trajectory models in calculations of N2-broadened half-widths and N2-induced line shifts for the rotational band of H216O and comparison with measurements

    International Nuclear Information System (INIS)

    In this work, Complex Robert-Bonamy calculations of half-widths and line shifts were done for N2-broadening of water for 1639 transitions in the rotational band using two models for the trajectories. The first is a model correct to second order in time, the Robert-Bonamy parabolic approximation. The second is the solution of Hamilton's equations. Both models use the isotropic part of the atom-atom potential to determine the trajectories. The present calculations used an intermolecular potential expanded to 20th order to assure the convergence of the half-widths and line shifts. The aim of the study is to assess if the difference in the half-widths and line shifts determined from the two trajectory models is greater than the accuracy requirements of the spectroscopic and remote sensing communities. The results of the calculations are compared with measurements of the half-widths and line shifts. It is shown that the effects of the trajectory model greatly exceed the needs of current remote sensing measurements and that line shape parameters calculated using trajectories determined by solving Hamilton's equations agree better with measurement.

  18. Level Width Broaden Effect

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang

    2004-01-01

    In fitting the double-differential measurements thelevelwidth broadening effect should be taken into account properly due to Heisenberg uncertainty.Besides level width broadening effect the energy resolution in the measurements is also needed in this procedure.In general,the traditional normal Gaussian expansion is employed.However,the research indicates that to do so in this way the energy balance could not hold.For this reason,the deformed Gaussian expansion functions with exponential form for both the single energy point and continuous spectrum are introduced,with which the normalization and energy balance conditions could hold exactly in the analytical form.

  19. A comparison of different methods for x-ray diffraction line broadening analysis of Ti and Ag UHV deposited thin films: nanostructural dependence on substrate temperature and film thickness

    International Nuclear Information System (INIS)

    The influence of substrate temperature and film thickness on the nanostructure of titanium (HCP) and silver (FCC) thin films deposited on glass substrates under UHV conditions by electron beam evaporation is investigated. The preferred orientation, nanostrain and stacking and twin fault probabilities in Ag and Ti films are determined as a function of film thickness and substrate temperature. A (111) preferred orientation is observed for silver films, which is dependent on both the film thickness and substrate temperature, with the highest value at a substrate temperature of 500 K. Ti/glass films showed a (002) preferred orientation. Nanostructural parameters such as the crystallite size (size of coherently diffracting domains) and nanostrain are evaluated using the Scherrer and Stocks-Wilson relations, the Williamson-Hall plot, and the single-Voigt (SV), double-Voigt (DV) and Warren-Averbach (WA) methods. Analysis of the results obtained using these methods showed that the most suitable approaches to x-ray diffraction line broadening analysis, applicable to both FCC and HCP polycrystalline thin film structures, are SV, DV and WA. The results show that the crystallite sizes increase with substrate temperature and film thickness, while the nanostrain and lattice constants decrease with thickness. The crystallite size distribution function was obtained from the size broadened part of the DV function, and the results show a shift in the maximum to larger sizes with increasing temperature and thickness

  20. Spectral shapes of Ar-broadened HCl lines in the fundamental band by classical molecular dynamics simulations and comparison with experiments

    Energy Technology Data Exchange (ETDEWEB)

    Tran, H., E-mail: ha.tran@lisa.u-pec.fr [Laboratoire Interuniversitaire des Systèmes Atmosphériques, UMR CNRS 7583, Université Paris Est Créteil, Université Paris Diderot, Institut Pierre-Simon Laplace, 94010 Créteil Cedex (France); Domenech, J.-L. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, (IEM-CSIC), Serrano 123, 28006 Madrid (Spain)

    2014-08-14

    Spectral shapes of isolated lines of HCl perturbed by Ar are investigated for the first time using classical molecular dynamics simulations (CMDS). Using reliable intermolecular potentials taken from the literature, these CMDS provide the time evolution of the auto-correlation function of the dipole moment, whose Fourier-Laplace transform leads to the absorption spectrum. In order to test these calculations, room temperature spectra of various lines in the fundamental band of HCl diluted in Ar are measured, in a large pressure range, with a difference-frequency laser spectrometer. Comparisons between measured and calculated spectra show that the CMDS are able to predict the large Dicke narrowing effect on the shape of HCl lines and to satisfactorily reproduce the shapes of HCl spectra at different pressures and for various rotational quantum numbers.

  1. ELECTRON-IMPACT BROADENING OF Cu IV LINES FOR THE DIAGNOSTIC OF THE ARC PLASMA OF ELECTRODYNAMIC MACRO-PARTICLE ACCELERATOR

    OpenAIRE

    Dimitrijevic, M.; Juric, Z.; Mihajlov, A.

    1989-01-01

    Using a model method of loss energy simulation on the boundary surfaces, temperature and composition of an electrodynamic macroparticle accelerator arc plasma created by the evaporation of a Cu foil, have been calculated. Stark widths for Cu IV lines of interest for the arc plasma diagnostic have been calculated also, by using the modified semiempirical method.

  2. Broadening the radiography spectrum

    International Nuclear Information System (INIS)

    The text discuses the mammography in breast screening and evaluation of breast cancer; Small parts ultrasounds at plaza imaging solutions; role of a Radiographer in mammography-new perspective; Medical imaging education in africa; Caring for the paediatric patient as to broaden radiotherapy spectrum; Problems and challenges in care for children undergoing radiotherapy; Paediatric radiotherapy, management and side effects; The principles of pattern recognition of skeletal structures; the place of distance learning education in broadening the radiography spectrum; the curriculum and budgeting image; sonographer's guide; Computed radiography- X-Ray with vision; digital Radiography in Kenya today; Particle Therapy at Ithemba Labs; The role of lung perfusion and ventilation study in the evaluation of the pulmonary embolism and lastly, an overview of Head and neck treatment at Kenyatta National hospital radiotherapy

  3. The STARK-B database VAMDC node: a repository for spectral line broadening and shifts due to collisions with charged particles

    Science.gov (United States)

    Sahal-Bréchot, S.; Dimitrijević, M. S.; Moreau, N.; Ben Nessib, N.

    2015-05-01

    Accurate spectroscopic diagnostics and modeling require the knowledge of numerous collisional line profiles. Access to such data via an online database has become indispensable. The STARK-B database is aimed at meeting these needs for widths and shifts of isolated lines of neutral and ionized elements due to electron and ion impacts. This database of the Paris Observatory is a result of scientific cooperation between S Sahal-Bréchot (LERMA) and M S Dimitrijević (AOB). Access to it is free, and it was opened online at the end of 2008. STARK-B is a node of the Virtual Atomic and Molecular Data Centre (VAMDC) and thus complies with VAMDC and Virtual Observatory standards. VAMDC is a European Union-funded collaboration among groups involved in the generation and use of interoperable atomic and molecular data. STARK-B now contains all our semiclassical-perturbation (SCP) calculated data for more than 123 neutral or ionized elements as published in international refereed journals. It is devoted to modeling and spectroscopic diagnostics of stellar atmospheres and envelopes, laboratory plasmas, laser equipment, and technological plasmas. Hence, the range of temperatures and densities covered by the tables is broad and depends on the ionization degree of the radiating atom. The modified semiempirical (MSE) results of calculations have begun to be implemented. In this paper, we highlight the key points of the method and the assumptions used in the calculations, which have lately been revisited. Then we present the database and its recent developments, as well as our ongoing work and our plans for the future.

  4. Experimental study of population inversion and spectral line broadening in a plasma containing a mixture of high Z and low Z ions

    International Nuclear Information System (INIS)

    In our work this past year at the University of Rochester's Laboratory for Laser Energetics we have studied laser-produced plasmas using spherical targets continuing layers of high Z and low Z materials. Our emphasis was on quantitative spectroscopy of ions in a very dense, recombining plasma. The targets used consisted of carbon-copper, carbon-gold, and aluminum-gold mixtures, instead of the originally proposed Fe or Mo mixtures with carbon. The thickness of the Cu and the Au layers were varied in order to study the effect of higher Z ions cooling the plasma. Indeed a pronounced cooling effect was observed by increasing the thickness of the Au layer in targets with Al-Au layers. Electron temperatures were studied by measuring the 1s-2p/1s2-1s2p line ratio of Al XIII to Al XII. Our experimental measurements, together with a collisional-radiative model and a 1-D hydrodynamic code, indicate that the electron temperature falls from 1500 eV with no gold to 950 eV with a 500 angstrom layer of gold. A detailed discussion of our results with Al-Au targets can be found in the enclosed preprint entitled Radiation Cooling in Laser-Produced Plasmas Due to High-Z Layers

  5. Measurement of the Temperature Dependence of Line Mixing and Pressure Broadening Parameters between 296 and 90 K in the v3 band of 12CH4 and their Influence on Atmospheric Methane Retrievals

    Science.gov (United States)

    Mondelain, Didier; Payan, Sebastien; Deng, Wenping; Camy-Peyret, Claude; Hurtmans, Daniel; Mantz, Arlan W.

    2007-01-01

    We measured the temperature dependence of the nitrogen broadening, narrowing and line-mixing coefficients of four lines of the P9 manifold in the v3 band of 12CH4 for atmospheric purposes. The data were collected using our tunable diode laser (TDL) spectrometer with active wavenumber control coupled to a newly developed cold Herriott cell with a path length of 5.37 m and a temperature uniformity of better than 0.01 K along the cell. We recorded and analyzed spectra recorded at sample temperature between 90 K and room temperature. We have investigate the influence of our new results in the inversion model used to retrieve methane profiles from atmospheric spectra; our new results make it possible to retrieve significantly more precise methane profiles. The atmospheric spectra we utilized were obtained by several of us with a balloon-born Fourier Transform infrared experiment in a limb configuration. Differences up to 7% on the retrieved volume mixing ratio were found compared to an inversion model using only HITRAN04 spectroscopic parameters.

  6. abo-cross: Hydrogen broadening cross-section calculator

    Science.gov (United States)

    Barklem, P. S.; Anstee, S. D.; O'Mara, B. J.

    2015-07-01

    Line broadening cross sections for the broadening of spectral lines by collisions with neutral hydrogen atoms have been tabulated by Anstee & O'Mara (1995), Barklem & O'Mara (1997) and Barklem, O'Mara & Ross (1998) for s-p, p-s, p-d, d-p, d-f and f-d transitions. abo-cross, written in Fortran, interpolates in these tabulations to make these data more accessible to the end user. This code can be incorporated into existing spectrum synthesis programs or used it in a stand-alone mode to compute line broadening cross sections for specific transitions.

  7. Narrowing of EIT resonance in a Doppler Broadened Medium

    OpenAIRE

    Javan, Ali; Kocharovskaya, Olga; Lee, Hwang; Scully, Marlan O.

    2001-01-01

    We derive an analytic expression for the linewidth of EIT resonance in a Doppler broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser induced line narrowing effect by Feld and Javan. In the limit of high intensity we recover the usual power broadening case where EIT linewidth is proportional to the intensity and inversely proporti...

  8. Broadening nanotechnology's impact on development

    Science.gov (United States)

    Beumer, Koen

    2016-05-01

    Discussions about nanotechnology and development focus on applications that directly address the needs of the world's poor. Nanotechnology can certainly make an impact in the fight against global poverty, but we need to broaden our imagination.

  9. Coherent Forward Broadening in Cold Atom Clouds

    CERN Document Server

    Sutherland, R T

    2015-01-01

    It is shown that homogeneous line-broadening in a diffuse cold atom cloud is proportional to the resonant optical depth of the cloud. Further, it is demonstrated how the strong directionality of the coherent interactions causes the cloud's spectra to depend strongly on its shape, even when the cloud is held at constant densities. These two numerical observations can be predicted analytically by extending the single photon wave-function model. Lastly, elongating a cloud along the line of laser propagation causes the excitation probability distribution to deviate from the exponential decay predicted by the Beer-Lambert law to the extent where the atoms in the back of the cloud are more excited than the atoms in the front. These calculations are conducted at low densities relevant to recent experiments.

  10. Coherent forward broadening in cold atom clouds

    Science.gov (United States)

    Sutherland, R. T.; Robicheaux, F.

    2016-02-01

    It is shown that homogeneous line-broadening in a diffuse cold atom cloud is proportional to the resonant optical depth of the cloud. Furthermore, it is demonstrated how the strong directionality of the coherent interactions causes the cloud's spectra to depend strongly on its shape, even when the cloud is held at constant densities. These two numerical observations can be predicted analytically by extending the single-photon wave-function model. Lastly, elongating a cloud along the line of laser propagation causes the excitation probability distribution to deviate from the exponential decay predicted by the Beer-Lambert law to the extent where the atoms at the back of the cloud are more excited than the atoms at the front. These calculations are conducted at the low densities relevant to recent experiments.

  11. Effect of Pressure Broadening on Molecular Absorption Cross Sections in Exoplanetary Atmospheres

    CERN Document Server

    Hedges, Christina

    2016-01-01

    Spectroscopic observations of exoplanets are leading to unprecedented constraints on their atmospheric compositions. However, molecular abundances derived from spectra are degenerate with the absorption cross sections which form critical input data in atmospheric models. Therefore, it is important to quantify the uncertainties in molecular cross sections to reliably estimate the uncertainties in derived molecular abundances. However, converting line lists into cross sections via line broadening involves a series of prescriptions for which the uncertainties are not well understood. We investigate and quantify the effects of various factors involved in line broadening in exoplanetary atmospheres - the profile evaluation width, pressure versus thermal broadening, broadening agent, spectral resolution, and completeness of broadening parameters - on molecular absorption cross sections. We use H$_2$O as a case study as it has the most complete absorption line data. For low resolution spectra (R$\\lesssim$100) for re...

  12. 锶原子窄线宽互组跃迁荧光谱获得及谱线增宽因素分析%Realization of Narrow Linewidth Fluorescence Spectrum of Strontium Intercombination Transition and Analysis of Its Line Broadening Factors

    Institute of Scientific and Technical Information of China (English)

    刘辉; 任洁; 田晓; 常宏

    2013-01-01

    The strontium (5s2)1S0-(5s5p)3P1 intercombination transition is characterized far narrower natural line width than its counterpart dipode transition line (5s2)1S0-(5s5p)3P1 and has been applied in the field of optical frequency standards.In order to obtain its high quality spectrum,the line broadening factors of strontium (5s2)1S0(5s5p)3 P1 intercombination transition fluorescence spectrum are theoretically analyzed based on thermal atomic beam collimated by capillary tubes.The factors,including Doppler effect,laser line width,saturation broadening and transit-time broadening,are considered.Experimentally,the fluorescence spectrum including the saturated fluorescence spectrum,is obtained from the differently collimated strontium thermal atomic beams.The exprimental results show that the higher collimated thermal beam's fluorescence spectrum line width is only 6.5 MHz,which is on the same order of magnitude as the Lamb-dip line width in the saturated fluorescence spectrum (1.7 MHz),and greatly reduces first-order Doppler broadening of spectra.And an external cavity diode laser is locked to the narrow line fluorescence spectrum by modulating the laser's frequency directly,achieving a laser line width of about 0.72 MHz.%锶原子(5s2)1S0-(5s5p)3P1互组跃迁自然线宽远窄于其单态间的(5s2)1S0-(5s5p)1P1偶极跃迁,在光频标中有着实际的应用.为获得该跃迁线的高质量光谱,从理论上分析了利用毛细管准直的热原子束中,锶原子(5s2)1S0-(5s5p)3P1互组跃迁荧光光谱的谱线增宽因素,包括多普勒增宽、激光线宽、饱和增宽和渡越增宽.利用不同准直度的原子束实验获得了该互组跃迁的荧光谱和饱和荧光谱,较高准直的原子束获得荧光谱线宽仅为6.5 MHz,与饱和荧光谱的兰姆凹陷线宽(1.7 MHz)在同一个数量级上,大大减小了谱线的一阶多普勒增宽.通过对频率直接调制将激光器锁定在该谱线上,锁定后激光的线宽约为0.72 MHz.

  13. Temperature Dependence of Stark Broadening Dominated by Strong Collisions

    International Nuclear Information System (INIS)

    The influence of electron temperature in the broadening of spectral lines dominated by strong collisions has been studied. Computer simulation allows us to study the effects of strong and weak collisions separately. Results shown here are focused on some Sr+ and Ba+ resonance lines as examples of lines broadened dominantly by strong collisions. The exact numerical integration of the perturbation process due to the collision with a single particle permits the evaluation of Weisskopf radius. This parameter is usually defined as rw ∼ 1/v ∼ 1/√T, obtained from Bora approximation that is correct for high temperatures. However, at low temperatures the full integration of the collision process permits to test the relationship rw ∼ 1/T1/6. This calculation has allowed us to study the influence of temperature on the broadening of the lines dominated by strong collisions. This study has been done in two ways : through a plasma simulation and analyzing the calculated Weisskopf radius for an individual collision. The obtained results show that at low temperatures the width of the line increases for increasing temperature as a consequence of an increase of the number of collisions not compensated by the decrease of Weisskopf radius

  14. Spectrally selective optical pumping in Doppler-broadened cesium atoms

    International Nuclear Information System (INIS)

    The D1 line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations. The process, described by a three-level model with the Λ scheme, shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms. The |Fg = 3> → |Fe = 4> resonance pumping can result in the ground state |Fg = 4, mF = 4> sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state Fg = 4. To enhance the anisotropy in the ground state, we suggest employing dichromatic optical HF pumping by adding a laser to excite D1 line |Fg = 4> → |Fe = 3> transition, in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth's average magnetic field. (atomic and molecular physics)

  15. Experimental study of the profiles of the Hsub(β) and HeI 43D, 3F-23P spectral lines broadened by Stark or Stark-Zeeman effect

    International Nuclear Information System (INIS)

    The profiles of the Hsub(β) (lambda=4861.32A) and HeI(lambda=4471.48A and lambda=4470.04A) lines emitted during the recombination phase of pulsed plasmas confined by magnetic fields (02 molecular spectrum during the recombination phase; a very strong coupling between Stark effect and Zeeman effect: consequently, the components of the normal Zeeman effect are shifted as the electron density increases

  16. Causes of EIT Intensity Correlation Power Broadening

    CERN Document Server

    Zheng, Aojie; Crescimanno, Michael; O'Leary, Shannon

    2015-01-01

    EIT noise correlation spectroscopy holds promise as a simple, robust method for performing high resolution spectroscopy used in optical magnetometry and clocks. Of relevance to these applications, we report here on a measurement of and a theory model for power broadening of EIT noise correlation resonances. Taken together they identify physical antecedents of noise correlation power broadening.

  17. Stark broadening data for stellar plasma research.

    Science.gov (United States)

    Dimitrijević, M. S.

    Results of an effort to provide to astrophysicists and physicists an as much as possible complete set of Stark broadening parameters needed for stellar opacity calculations, stellar atmosphere modelling, abundance determinations and diagnostics of different plasmas in astrophysics, physics and plasma technology, are presented. Stark broadening has been considered within the semiclassical perturbation, and the modified semiempirical approaches.

  18. Experimental transition probabilities and Stark-broadening parameters of neutral and single ionized tin

    Science.gov (United States)

    Miller, M. H.; Roig, R. A.; Bengtson, R. D.

    1979-01-01

    Strengths and Stark-effect widths of the Sn I and Sn II lines prominent between 3200 and 7900 A are measured with a spectroscopic shock tube. Absolute strengths of 17 ionic lines are obtained with estimated (22-50)% accuracy and conform to appropriate quantum-mechanical sum rules. Relative transition probabilities for nine prominent neutral tin lines, normalized to radiative-lifetime data, are compared with other experiments and theoretical predictions. Parameters for Stark-effect broadening are measured over a range of plasma electron densities. Broadening data (with accuracies of 15-35%) for one neutral and ten ionic lines of tin are compared to theoretical predictions.

  19. Dipole-dipole broadening of Rb ns-np microwave transitions

    International Nuclear Information System (INIS)

    The dipole-dipole broadening of ns-np microwave transitions of cold Rb Rydberg atoms in a magneto-optical trap has been recorded for 28≤n≤51. Since the electric dipole transition matrix elements scale as n2, a broadening rate scaling as n4 is expected and a broadening rate of 8.2x10-15n4 MHz cm3 is observed. The observed broadening is smaller than expected from a classical picture due to the spin-orbit interaction in the np atoms. The broadened resonances are asymmetric and cusp shaped, and their line shapes can be reproduced by a diatomic model which takes into account the dipole-dipole interaction, including the spin-orbit interaction, the strengths of the allowed microwave transitions, and the distribution of the atomic spacings in the trap.

  20. Correction of Doppler-broadened Rayleigh backscattering effects in H2O dial measurements

    Science.gov (United States)

    Ansmann, A.; Bosenberg, J.

    1986-01-01

    A general method of solutions for treating effects of Doppler-broadened Rayleigh backscattering in H2O Differential Absorption Lidar (DIAL) measurements are described and discussed. Errors in vertical DIAL measuremtns caused by this laser line broadening effect can be very large and, therfore, this effect has to be accounted for accurately. To analyze and correct effects of Doppler-broadened Rayleigh backscattering in DIAL experiments, a generalized DIAL approximation was derived starting from a lidar equation, which includes Doppler broadening. To evaluate the accuracy of H2O DIAL measurements, computer simulations were performed. It was concluded that correction of Doppler broadened Rayleigh backscattering is possible with good accuracy in most cases of tropospheric H2O DIAL measurements, but great care has to be taken when layers with steep gradients of Mie backscattering like clouds or inversion layers are present.

  1. Interatomic potentials for the ground state X {sup 1}0{sup +} and the two excited states {sup 3}1, {sup 3}0{sup +} of the intercombination cadmium line 326.1 nm broadened by Kr pressure

    Energy Technology Data Exchange (ETDEWEB)

    Roston, G.D. [Physics Department, Faculty of Science, Alexandria University, P.O. Box 21511, Alexandria (Egypt)], E-mail: gamal_daniel@yahoo.com; Ghatass, Z.F. [Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horrya Avenue, P.O. 832 Shatby, Alexandria (Egypt)

    2008-09-15

    The temperature dependence of the Cd line absorption profile at 326.1 nm perturbed by Kr has been carefully studied over a spectral range extending from 800 cm{sup -1} in the blue wing to 1200 cm{sup -1} in the red wing using a high-resolution double-beam spectrometer. The atomic densities of krypton (N{sub Kr}) and cadmium (N{sub Cd}) were (2.015{+-}0.07)x10{sup 19} and (3.62{+-}0.05)x10{sup 18} cm{sup -3}, respectively. The temperature dependence of the studied line profile was analyzed in the framework of the quasi-static theory. The van der Waals coefficient differences between the ground {sup 1}0{sup +} state and the two excited states {sup 3}0{sup +} and {sup 3}1 ({delta}C{sub 6}{sup 0} and {delta}C{sub 6}{sup 1}) were obtained from the near red wing profile using Kuhn's law. The values of {delta}C{sub 6}{sup 0} and {delta}C{sub 6}{sup 1} are found to be equal to 37.8{+-}2 and 58.5{+-}3 eV A{sup 6}, respectively. The ground (X {sup 1}0{sup +}), and the excited ({sup 3}1, {sup 3}0{sup +}) state potentials at the internuclear separations from 3.2 to 6.3 A were determined. The well depths with their positions for these states are respectively equal to 134{+-}7 cm{sup -1}, 3.95{+-}0.2 A; 72.3{+-}4 cm{sup -1}, 4.95{+-}0.3 A; and 471{+-}12 cm{sup -1}, 3.6 A. The obtained well depths with their allowable errors are in good agreement with the values obtained before for the Cd-Kr system from some theoretical results and molecular beams experiments.

  2. FDBACE code for fast Doppler broadening ACE format based on parallel processing

    International Nuclear Information System (INIS)

    Highlights: • For fast and exact broadening of the ACE data tables, we used a new broadening algorithm. • A new code called FDBACE has been developed which generates high temperature ACE files. • This code can be easily converted to a module for using internally in Monte Carlo code. • A parallel algorithm is used for fast broadening based on shared memory scheme. - Abstract: In this article we introduce a code called FDBACE (Fast Doppler Broadening ACE) which has been developed as a tool for MCNP users to enhance the generation of high temperature ACE data tables. In this code, we developed new broadening, thinning and unionization subroutines, implemented in FORTRAN programming language, for directly broadening the ACE data table at desired temperature. For fast and exact broadening of the ACE data tables, we used a new parallel broadening algorithm based on the kernel broadening approach and shared memory scheme (using OpenMP). The thermal scattering table for molecules and crystalline solids, and probability table for unresolved resonances are computed by interpolating data between two bracketing temperatures. This code, which reads the ACE data table file and broadens it to the desired temperature and then writes it to a new ACE data table file, can be easily converted to an internal module embedded in Monte Carlo source code for In-line Doppler broadening. Accuracy, performance and formatting of FDBACE are evaluated for validation of the proposed method by three different test cases. The results obtained from FDBACE code, shows that it has a good performance over previous codes such as NJOY, SIGACE and MAKXSF in generating high temperature ACE data tables

  3. LINES

    Directory of Open Access Journals (Sweden)

    Minas Bakalchev

    2015-10-01

    Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.

  4. Ab Initio Computation of Dynamical Properties: Pressure Broadening

    Science.gov (United States)

    Wiesenfeld, Laurent; Drouin, Brian

    2014-06-01

    Rotational spectroscopy of polar molecules is the main observational tool in many areas of astrophysics, for gases of low densities (n ˜ 102 - 108 cm-3). Spectral line shapes in astrophysical media are largely dominated by turbulence-induced Doppler effects and natural line broadening are negligible. However line broadening remains an important tool for denser gases, like planetary high atmospheres. Understanding the excitation schemes of polar molecules requires the knowledge of excitation transfer rate due to collisional excitation, between the polar molecule and the ambient gas, usually H2. Transport properties in ionized media also require a precise knowledge of momentum transfer rates by elastic collisions. In order to assess the theoretically computed cross section and energy/momentum transfer rates, direct absolute experiments are scarce. The best way is to measure not individual scattering events but rather the global effect of the buffer gas, thanks to the pressure broadening cross sections, whose magnitude can be measured without any scaling parameters. At low temperatures, both elastic and inelastic scattering amplitudes are tested. At higher temperature, depending on the interaction strength, only inelastic scattering cross section are shown to play a significant role 1 ,2. Thanks to the advances of computer capabilities, it has become practical to compute spectral line parameters fromab initio quantum chemistry. In particular, the theory of rotational line broadening is readily incorporated into scattering quantum dynamical theory, like close-coupling schemes. The only approximations used in the computation are the isolated collision/isolated line approximations. We compute the non-binding interaction potential with high precision quantum chemistry and fit the resulting ab initio points onto a suitable functional. We have recently computed several such systems, for molecules in H2 buffer gas: H2O,3 H2CO,4 HCO+ .5 Detailed computations taking into

  5. Pulsed Spin Locking in Spin-1 NQR: Broadening Mechanisms

    Science.gov (United States)

    Malone, Michael W.

    Nuclear Quadrupole Resonance (NQR) is a branch of magnetic resonance physics that allows for the detection of spin I > 1/2 nuclei in crystalline and semi-crystalline materials. Through the application of a resonant radio frequency (rf) pulse, the nuclei's response is to create an oscillating magnetic moment at a frequency unique to the target substance. This creates the NQR signal, which is typically weak and rapidly decaying. The decay is due to the various line broadening mechanisms, the relative strengths of which are functions of the specific material, in addition to thermal relaxation processes. Through the application of a series of rf pulses the broadening mechanisms can be refocused, narrowing the linewidth and extending the signal in time. Three line broadening mechanisms are investigated to explain the NQR signal's linewidth and behavior. The first, electric field gradient (EFG) inhomogeneity, is due to variations in the local electric environment among the target nuclei, for instance from crystal imperfections. While EFG inhomogeneity can vary between samples of the same chemical composition and structure, the other broadening mechanisms of homonuclear and heteronuclear dipolar coupling are specific to this composition and structure. Simple analytical models are developed that explain the NQR signal response to pulse sequences by accounting for the behavior of each broadening mechanism. After a general theoretical introduction, a model of pairs of spin-1 nuclei is investigated, and the refocusing behaviors of EFG and homonuclear dipolar coupling are analyzed. This reveals the conditions where EFG is refocused but homonuclear dipolar coupling is not. In this case the resulting signal shows a rapid decay, the rate of which becomes a measure of interatomic distances. This occurs even in the more complex case of a powder sample with its many randomly oriented crystallites, under particular pulsing conditions. Many target NQR compounds are rich in hydrogen

  6. Speed-dependent effects and Dicke narrowing in nitrogen-broadened oxygen

    Science.gov (United States)

    Wójtewicz, S.; Masłowski, P.; Cygan, A.; Wcisło, P.; Zaborowski, M.; Piwiński, M.; Ciuryło, R.; Lisak, D.

    2015-11-01

    We present the line-shape analysis of the nitrogen-broadened P9 P9 oxygen B-band transition measured by the optical frequency comb-assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer. Perturbation by both oxygen and nitrogen molecules is taken into account simultaneously in the line-shape analysis. Several line-shape models describing physical effects such as Dicke narrowing, the speed dependence of collisional broadening and shifting, and the correlation between velocity- and phase-changing collisions were used in the analysis. The comparison between the hypergeometric and quadratic approximations of the speed-dependent effects is presented. Observed line narrowing is mostly determined by the speed dependence of the collisional broadening.

  7. Effect of pressure broadening on molecular absorption cross sections in exoplanetary atmospheres

    Science.gov (United States)

    Hedges, Christina; Madhusudhan, Nikku

    2016-05-01

    Spectroscopic observations of exoplanets are leading to unprecedented constraints on their atmospheric compositions. However, molecular abundances derived from spectra are degenerate with the absorption cross-sections which form critical input data in atmospheric models. Therefore, it is important to quantify the uncertainties in molecular cross-sections to reliably estimate the uncertainties in derived molecular abundances. However, converting line lists into cross-sections via line broadening involves a series of prescriptions for which the uncertainties are not well understood. We investigate and quantify the effects of various factors involved in line broadening in exoplanetary atmospheres - the profile evaluation width, pressure versus thermal broadening, broadening agent, spectral resolution and completeness of broadening parameters - on molecular absorption cross-sections. We use H2O as a case study as it has the most complete absorption line data. For low-resolution spectra (R ≲ 100) for representative temperatures and pressures (T ˜ 500-3000 K, P ≲ 1 atm) of H2-rich exoplanetary atmospheres, we find the median difference in cross-sections (δ) introduced by various aspects of pressure broadening to be ≲1 per cent. For medium resolutions (R ≲ 5000), including those attainable with James Webb Space Telescope, we find that δ can be up to 40 per cent. For high resolutions (R ˜ 105), δ can be ≳100 per cent, reaching ≳1000 per cent for low temperatures (T ≲ 500 K) and high pressures (P ≳ 1 atm). The effect is higher still for self-broadening. We generate a homogeneous data base of absorption cross-sections of molecules of relevance to exoplanetary atmospheres for which high-temperature line lists are available, particularly H2O, CO, CH4, CO2, HCN, and NH3.

  8. Quasilinear Line Broadened Model for Energetic Particle Transport

    Science.gov (United States)

    Ghantous, Katy; Gorelenkov, Nikolai; Berk, Herbert

    2011-10-01

    We present a self-consistent quasi-linear model that describes wave-particle interaction in toroidal geometry and computes fast ion transport during TAE mode evolution. The model bridges the gap between single mode resonances, where it predicts the analytically expected saturation levels, and the case of multiple modes overlapping, where particles diffuse across phase space. Results are presented in the large aspect ratio limit where analytic expressions are used for Fourier harmonics of the power exchange between waves and particles, . Implemention of a more realistic mode structure calculated by NOVAK code are also presented. This work is funded by DOE contract DE-AC02-09CH11466.

  9. Sound pulse broadening in stressed granular media.

    Science.gov (United States)

    Langlois, Vincent; Jia, Xiaoping

    2015-02-01

    The pulse broadening and decay of coherent sound waves propagating in disordered granular media are investigated. We find that the pulse width of these compressional waves is broadened when the disorder is increased by mixing the beads made of different materials. To identify the responsible mechanism for the pulse broadening, we also perform the acoustic attenuation measurement by spectral analysis and the numerical simulation of pulsed sound wave propagation along one-dimensional disordered elastic chains. The qualitative agreement between experiment and simulation reveals a dominant mechanism by scattering attenuation at the high-frequency range, which is consistent with theoretical models of sound wave scattering in strongly random media via a correlation length. PMID:25768496

  10. Parton Energy Loss Without Transverse Momentum Broadening

    CERN Document Server

    Zapp, Korinna; Rathsman, Johan; Stachel, Johanna; Wiedemann, Urs Achim

    2011-01-01

    The JEWEL 1.0 Monte Carlo simulates jet evolution in a medium with a microscopic description of splitting and scattering processes. In the framework of this model we investigate the transverse momentum broadening due to medium effects in different scenarios. Depending on assumptions about hadronisation, we observe either a small increase or even a slight decrease of the mean transverse momentum, but no sizeable broadening. This appears to be a natural consequence of a model formulation which conserves energy and momentum microscopically at each splitting and at each scattering.

  11. Spectrally selective optical pumping in Doppler-broadened cesium atoms

    Institute of Scientific and Technical Information of China (English)

    Zhang Jun-Hai; Zeng Xian-Jin; Li Qing-Meng; Huang Qiang; Sun Wei-Min

    2013-01-01

    The D1 line spectrally selective pumping process in Doppler-broadened cesium is analyzed by solving the optical Bloch equations.The process,described by a three-level model with the A scheme,shows that the saturation intensity of broadened atoms is three orders of magnitude larger than that of resting atoms.The |Fg =3> → |Fe-4> resonance pumping can result in the ground state |Fg =4,mF =4> sublevel having a maximum population of 0.157 and the population difference would be about 0.01 in two adjacent magnetic sublevels of the hyperfine (HF) state Fg =4.To enhance the anisotropy in the ground state,we suggest employing dichromatic optical HF pumping by adding a laser to excite D1 line |Fg =4> → |Fe =3>transition,in which the cesium magnetometer sensitivity increases by half a magnitude and is unaffected by the nonlinear Zeeman effect even in Earth's average magnetic field.

  12. Broadening Our View of Linguistic Diversity

    Science.gov (United States)

    O'Neal, Debra; Ringler, Marjorie

    2010-01-01

    The definition of English language learners needs to be broadened to include the marginalized dialects of English. Not all native speakers speak Standard English, and even those who do need to learn Academic English to succeed in school. By using strategies developed for ELLs, teachers can help all students become fluent in the language of school.

  13. Collisional broadening of alkali doublets by helium perturbers

    CERN Document Server

    Mullamphy, D F T; Peach, G; Venturi, V; Whittingham, I B

    2006-01-01

    We report results for the Lorentzian profiles of the Li I, Na I and K I doublets and the Na I subordinate doublet broadened by helium perturbers for temperatures up to 3000 K They have been obtained from a fully quantum-mechanical close-coupling description of the colliding atoms, the Baranger theory of line shapes and new ab initio potentials for the alkali-helium interaction. For all lines except the 769.9 nm K I line, the temperature dependence of the widths over the range 70 < T < 3000 K is accurately represented by the power law form w=aT^b with 0.37 < b < 0.43. The 769.9 K I line has this form for 500 < T < 3000 K with b = 0.49. Although the shifts have a more complex temperature dependence, they all have the general feature of increasing with temperature above T=500 K apart from the 769.9 K I line whose shift decreases with temperature.

  14. Dynamic Stark broadening as the Dicke narrowing effect

    Science.gov (United States)

    Calisti, A.; Mossé, C.; Ferri, S.; Talin, B.; Rosmej, F.; Bureyeva, L. A.; Lisitsa, V. S.

    2010-01-01

    A very fast method to account for charged particle dynamics effects in calculations of spectral line shape emitted by plasmas is presented. This method is based on a formulation of the frequency fluctuation model (FFM), which provides an expression of the dynamic line shape as a functional of the static distribution of frequencies. Thus, the main numerical work rests on the calculation of the quasistatic Stark profile. This method for taking into account ion dynamics allows a very fast and accurate calculation of Stark broadening of atomic hydrogen high- n series emission lines. It is not limited to hydrogen spectra. Results on helium- β and Lyman- α lines emitted by argon in microballoon implosion experiment conditions compared with experimental data and simulation results are also presented. The present approach reduces the computer time by more than 2 orders of magnitude as compared with the original FFM with an improvement of the calculation precision, and it opens broad possibilities for its application in spectral line-shape codes.

  15. Porous silicon bandgap broadening at natural oxidation

    International Nuclear Information System (INIS)

    Emission and excitation photoluminescence spectra of porous silicon thin layers have been investigated at natural oxidation. The shift of both types of spectra to high-energy region with time has been shown. Analysis of excitation spectra points out the indirect behavior of electron transitions responsible for visible photoluminescence, which remains unaltered at natural oxidation. The value of optical bandgap is estimated in each case. It is shown that the optical bandgap broadens during oxidation due to size reduction of silicon nanocrystallites. - Highlights: → Porous silicon emission and excitation spectra blue shifted at natural oxidation. → Excitation spectra points out the indirect behavior of electron transitions. → Optical bandgap broadens during oxidation due to Si nanoparticles size reduction.

  16. Influence of elastic and inelastic collisions on density shift and broadening

    NARCIS (Netherlands)

    Weber, Erhard W.; Jungmann, Klaus-Peter

    1981-01-01

    For the Na D lines the shift and width of resolved hyperfine structure components are measured in He buffer gas with high-resolution laser saturation spectroscopy. The data obtained differ from those measured with Doppler-broadened optical spectroscopy. To explain the different values the existing d

  17. Particle size and strain broadening in energy-dispersive x-ray powder patterns

    DEFF Research Database (Denmark)

    Gerward, Leif; Mørup, Steen; Topsøe, Haldor

    1976-01-01

    An energy-dispersive x-ray method for a rapid analysis of the broadening of diffraction lines in powder patterns has been developed. Experimental results are given for magnetite powders with sizes in the range 50–200 Å and compared with the results of standard angle-dispersive diffractometry...

  18. On pulse broadening for optical solitons

    CERN Document Server

    Dorren, H J S

    1999-01-01

    Pulse broadening for optical solitons due to birefringence is investigated. It is shown that in optical fibers with birefringence no pure solitons exist. We present analytical expressions for special solitonic solutions in birefringent optical fibers consisting of a combination of pure solitons propagating along the principal birefringence axis with a different velocity and interaction terms between the solitons. An estimation for the stability of the derived solutions and random polarization mode dispersion is given.

  19. Impact broadening of the dt. mu. formation resonances

    Energy Technology Data Exchange (ETDEWEB)

    Padial, N.T.; Cohen, J.S.; Leon, M.

    1988-08-01

    The density dependence of dt..mu.. molecular formation has been treated as a line-broadening process in the impact approximation. In the present paper, elastic cross sections and their coherent difference are calculated for D/sub 2/+D/sub 2/ and (dt..mu..)dee+D/sub 2/ collisions. Together with the rotationally inelastic cross sections previously calculated (Phys. Rev. A 37, 329 (1988)) using the same accurate intermolecular potential, this provides all cross sections needed for evaluation of the width in the impact approximation. The impact width is dominated by elastic scattering and, at the temperature 23 K and liquid-hydrogen density, has the value 14 meV, which is more than three times the previously calculated value.

  20. Spectral broadening in lithium niobate in a self-diffraction geometry using ultrashort pulses

    Science.gov (United States)

    Dharmadhikari, Jayashree A.; Dota, Krithika; Mathur, Deepak; Dharmadhikari, Aditya K.

    2016-05-01

    We report on broadband light generation in the impulsive regime in an un-doped lithium niobate (LiNbO3) crystal by two femtosecond laser pulses (36 fs) from a Ti-sapphire laser amplifier. We systematically investigate the role of incident intensity on spectral broadening. At relatively low incident intensity (0.7 TW cm-2), spectral broadening in the transmitted beam occurs due to the combined effect of self-phase modulation and cross-phase modulation. At higher incident intensity (10.2 TW cm-2), we observe generation of as many as 21 anti-Stokes orders due to coherent anti-Stokes Raman scattering in self-diffraction geometry. Moreover, we observe order-dependent spectral broadening of anti-Stokes lines that may be attributed to the competition with other nonlinear optical effects like cross-phase modulation.

  1. Broadening of dielectric response and sum rule conservation

    International Nuclear Information System (INIS)

    Different types of broadening of the dielectric response are studied with respect to the preservation of the Thomas–Reiche–Kuhn sum rule. It is found that only the broadening of the dielectric function and transition strength function conserve this sum rule, whereas the broadening of the transition probability function (joint density of states) increases or decreases the sum. The effect of different kinds of broadening is demonstrated for interband and intraband direct electronic transitions using simplified rectangular models. It is shown that the broadening of the dielectric function is more suitable for interband transitions while broadening of the transition strength function is more suitable for intraband transitions. - Highlights: • Preservation of the sum rule by different types of dielectric response broadening • Only broadening of dielectric function and transition strength function preserves it. • Broadening of joint density of states does not preserve the sum rule. • Broadening of dielectric function is better for direct interband transitions. • Broadening of transition strength is better for indirect interband transitions

  2. A broadened typology on energy and security

    International Nuclear Information System (INIS)

    A broadened typology describing the interconnection between energy and security is developed in this paper, with the aim of improving understanding of the relationship between energy and security by applying different research and policy perspectives. One approach involves studying energy as an object exposed to security threats, using concepts such as security of supply or security of demand. Another approach involves studying the role of the energy system as the subject in generating or enhancing insecurity. The latter approach includes studying the conflict-generating potential inherent in the economic value of energy, the risk of accidents and antagonistic attacks to energy infrastructure and the security risks related to the negative environmental impact of the energy system. In order to make a comprehensive analysis of the security consequences of proposed energy policies or strategies, all these aspects should be taken into account to varying degrees. The typology proposed here could be a valuable tool for ensuring that all security aspects have been considered. - Highlights: • The paper presents a broadened typology of energy and security, useful for policy analysis. • The energy system can be an object for security threats and as a subject generating or contributing to insecurity. • Energy as an object for security threats includes the concepts of security of supply and security of demand. • The economic value of energy can contribute to insecurity. • Technological and environmental risks of specific energy systems also provide potential threats to human security

  3. Windowed multipole for cross section Doppler broadening

    Science.gov (United States)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  4. Commitment to Broadening Participation at NOAO

    Science.gov (United States)

    Garmany, Catharine D.; Norman, D.

    2011-01-01

    AURA and NOAO take seriously the importance of Broadening Participation in Astronomy. At the request of the AURA President, each of the AURA centers (NOAO, NSO, STSCI, Gemini) appointed a Diversity Advocates (DA). At NOAO this job is shared by Dara Norman and Katy Garmany, who were appointed by Dave Silva in Jan 2009. The DA's are members of the AURA Committee on Workforce and Diversity (WDC), a designated subcommittee of the AURA Board of Directors. The role of this committee includes reviewing activities and plans on an AURA wide basis aimed at broadening the participation within AURA, and reviewing AURA wide policies on the workforce. At NOAO, the role of the DAs spans a number of departments and activities. They serve on observatory search committees, and offer suggestions on how NOAO job searches can reach the most diverse audience. The DA's job is to insure that NOAO actively pursues every opportunity to increase diversity: to this end they are involved in outreach and educational activities that focus on workplace development and encourage inclusion of woman, minorities and persons with disabilities.

  5. Action potential broadening in a presynaptic channelopathy

    Science.gov (United States)

    Begum, Rahima; Bakiri, Yamina; Volynski, Kirill E.; Kullmann, Dimitri M.

    2016-07-01

    Brain development and interictal function are unaffected in many paroxysmal neurological channelopathies, possibly explained by homoeostatic plasticity of synaptic transmission. Episodic ataxia type 1 is caused by missense mutations of the potassium channel Kv1.1, which is abundantly expressed in the terminals of cerebellar basket cells. Presynaptic action potentials of small inhibitory terminals have not been characterized, and it is not known whether developmental plasticity compensates for the effects of Kv1.1 dysfunction. Here we use visually targeted patch-clamp recordings from basket cell terminals of mice harbouring an ataxia-associated mutation and their wild-type littermates. Presynaptic spikes are followed by a pronounced afterdepolarization, and are broadened by pharmacological blockade of Kv1.1 or by a dominant ataxia-associated mutation. Somatic recordings fail to detect such changes. Spike broadening leads to increased Ca2+ influx and GABA release, and decreased spontaneous Purkinje cell firing. We find no evidence for developmental compensation for inherited Kv1.1 dysfunction.

  6. Structure and broadening coefficients (He, Ar and N2) of the ν4 band of CF4

    International Nuclear Information System (INIS)

    Spectra of CF4 in the ν4 fundamental band region have been recorded in pure gas and in mixtures with He, Ar and N2 at resolution up to 0.003 cm-1. Obtained data allowed us to evaluate the integrated band intensity, line intensity distribution and effective broadening coefficients for J-multiplets. The broadening coefficient behavior is similar to that previously registered for linear molecules: they coincide for P and R branches; the J-dependence in the case of argon is more pronounced than that for helium. The broadening coefficients for nitrogen and helium are practically the same but the values for nitrogen are scattered around the general trend. Q-branch broadening is different from that for J-manifolds. The coefficients of branch broadening are noticeably smaller. Nitrogen broadening is very close to result for the case of argon though there is a marked difference between them for J-manifolds. Collisions with argon and nitrogen broaden the Q-branch almost 3 times more effectively than collisions with helium

  7. CH3Cl self-broadening coefficients and their temperature dependence

    International Nuclear Information System (INIS)

    CH335Cl self-broadening coefficients at various temperatures of atmospheric interest are computed by a semi-empirical method particularly suitable for molecular systems with strong dipole–dipole interactions. In order to probe the dependence on the rotational number K, the model parameters are adjusted on extensive room-temperature measurements for K≤7 and allow reproducing fine features of J-dependences observed for K≤3; for higher K up to 20, the fitting is performed on specially calculated semi-classical values. The temperature exponents for the standard power law are extracted and validated by calculation of low-temperature self-broadening coefficients comparing very favorably with available experimental data. An extensive line-list of self-broadening coefficients at the reference temperature 296 K and associated temperature exponents for 0≤J≤70, 0≤K≤20 is provided as Supplementary material for their use in atmospheric applications and spectroscopic databases. -- Highlights: • We calculated methyl chloride self-broadening coefficients using two methods. • Rotational quantum numbers were J from 0 till 70 and K from 0 till 20. • The temperature exponents were calculated for every mentioned line

  8. RESONANCE BROADENING AND HEATING OF CHARGED PARTICLES IN MAGNETOHYDRODYNAMIC TURBULENCE

    International Nuclear Information System (INIS)

    The heating, acceleration, and pitch-angle scattering of charged particles by magnetohydrodynamic (MHD) turbulence are important in a wide range of astrophysical environments, including the solar wind, accreting black holes, and galaxy clusters. We simulate the interaction of high-gyrofrequency test particles with fully dynamical simulations of subsonic MHD turbulence, focusing on the parameter regime with β ∼ 1, where β is the ratio of gas to magnetic pressure. We use the simulation results to calibrate analytical expressions for test particle velocity-space diffusion coefficients and provide simple fits that can be used in other work. The test particle velocity diffusion in our simulations is due to a combination of two processes: interactions between particles and magnetic compressions in the turbulence (as in linear transit-time damping; TTD) and what we refer to as Fermi Type-B (FTB) interactions, in which charged particles moving on field lines may be thought of as beads sliding along moving wires. We show that test particle heating rates are consistent with a TTD resonance that is broadened according to a decorrelation prescription that is Gaussian in time (but inconsistent with Lorentzian broadening due to an exponential decorrelation function, a prescription widely used in the literature). TTD dominates the heating for vs >> vA (e.g., electrons), where vs is the thermal speed of species s and vA is the Alfvén speed, while FTB dominates for vs A (e.g., minor ions). Proton heating rates for β ∼ 1 are comparable to the turbulent cascade rate. Finally, we show that velocity diffusion of collisionless, large gyrofrequency particles due to large-scale MHD turbulence does not produce a power-law distribution function.

  9. Broadening the focus of evaluation: An experiment

    Directory of Open Access Journals (Sweden)

    Chakraborty, S.

    2010-01-01

    Full Text Available Evaluation of student performance in any course, especially those delivered in a management programme, poses a serious challenge; more so, in a course like ‘Business Communication’, where oral communication ought to form an integral part of evaluation. This paper presents various details of an experiment, conducted with a view to introduce this much needed component in the evaluation process. Essential purpose of the exercise was to try and broaden the focus of evaluation, simultaneously enlarging its scope. The need to maintain certain amount of objectivity and transparency was taken as critical. Group Discussion was used as a tool. A process was developed with the objective of getting every student evaluated on both written as well as non-written skills. A two-sided evaluation mechanism was put in place to achieve the dual purpose of leaning and evaluation. Statistical analysis of the results suggests that the experiment was a useful one. The student feedback, too, was favourable.

  10. Analysis of pressure-broadened ozone spectra in the 3 micron region

    Science.gov (United States)

    Prochaska, Eleanor S.

    1991-01-01

    This work involves the analysis of a series of McMath Fourier Transform Infrared (FTIR) spectra of ozone broadened by mixing with air (four different pressures), nitrogen (three pressures), or oxygen (three pressures). Each spectrum covers the region from 2396 to 4057 cm(-1). This study focused on the 3 sub nu sub 3 band in t 3000 to 3060 cm(-1). The band is analyzed by first dividing its region into small intervals containing a few well isolated absorption lines of reasonable intensity. Each of these small intervals is fit by multiple iterations of the nonlinear least squares program until residuals (the difference between calculated and observed spectrum, as a percent of the strongest intensity in the interval) are minimized to a reasonable value which corresponds to the noise level of the measured spectrum. Position, intensity, and half-width are recorded for later analysis. From the measured half-widths, a pressure broadening coefficient was determined for each absorption line. Pressure shifts were determined by comparing observed line positions in the spectra of the diluted ozone samples to tabulated line positions determined from spectra of pure gas samples. Comparisons to other work on ozone indicate that the broadening and shift coefficients determined in this study are consistent with those determined in other spectral regions.

  11. Study of Compton Broadening Due to Electron-Photon Scattering

    Directory of Open Access Journals (Sweden)

    Srinivasa Rao, M.

    2010-06-01

    Full Text Available We have investigated the effects of Compton broadening due to electron-photon scattering in hot stellar atmospheres. A purely electron-photon scattering media is assumed to have plane parallel geometry with an input radiation field localized on one side of the slab. The method is based on the discrete space theory of radiative transfer for the intensity of emitted radiation.The solution is developed to study the importance of scattering of radiation by free electrons in high temperature stellar atmospheres which produces a brodening and shift in spectral lines because of the Compton effect and the Doppler effect arising from mass and thermal motions of scattering electrons.It is noticed that the Comptonized spectrum depends on three parameters: the optical depth of the medium, the temperature of the thermal electrons and the viewing angle.We also showed that the Compton effect produces red shift and asymmetry in the line. These two effects increase as the optical depth increases. It is also noticed that the emergent specific intensities become completely asymmetric for higher optical depths.

  12. Parton Energy Loss and Momentum Broadening at NLO in High Temperature QCD Plasmas

    Science.gov (United States)

    Ghiglieri, Jacopo; Teaney, Derek

    We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark-gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include 2 ↔ 2 scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light-cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.

  13. Parton energy loss and momentum broadening at NLO in high temperature QCD plasmas

    CERN Document Server

    Ghiglieri, Jacopo

    2015-01-01

    We present an overview of a perturbative-kinetic approach to jet propagation, energy loss, and momentum broadening in a high temperature quark-gluon plasma. The leading-order kinetic equations describe the interactions between energetic jet-particles and a non-abelian plasma, consisting of on-shell thermal excitations and soft gluonic fields. These interactions include 22 scatterings, collinear bremsstrahlung, and drag and momentum diffusion. We show how the contribution from the soft gluonic fields can be factorized into a set of Wilson line correlators on the light cone. We review recent field-theoretical developments, rooted in the causal properties of these correlators, which simplify the calculation of the appropriate Wilson lines in thermal field theory. With these simplifications lattice measurements of transverse momentum broadening have become possible, and the kinetic equations describing parton transport have been extended to next-to-leading order in the coupling g.

  14. Broadening and deepening or broadening versus deepening: The question of enlargement and Europe's 'hesitant Europeans'

    OpenAIRE

    Karp, Jeffrey A.; Bowler, Shaun

    2006-01-01

    The European Union sees the inclusion of many Eastern European states -enlargement- as a natural progression in the process of building an 'ever closer union'. For the European Commission in particular, the process of enlargement (broadening) is part of the process of integration and acts as a complement to the development of a stronger role for the European Union and its institutions or deepening of integration. Yet as the first Irish referendum on the Nice Treaty showed, not all of European...

  15. Theory of Excitation Broadening Using Time-Dependent Density Functional Theory for Open Quantum Systems

    OpenAIRE

    Tempel, David G.; Aspuru-Guzik, Alan

    2010-01-01

    The Casida equations of linear response TDDFT are extended to calculate linear spectra of open quantum systems evolving according to a Markovian master equation. By mapping a many-body open quantum system onto an open, non-interacting Kohn-Sham system, extrinsic line broadening due to electron-bath coupling can be described exactly within TDDFT. The structure of the resulting matrix equations are analyzed for the generic case of electrons linearly coupled to a harmonic bath within Redfield th...

  16. N2-broadening coefficients of methyl chloride at room temperature

    International Nuclear Information System (INIS)

    Methyl chloride is of interest for atmospheric applications, since this molecule is directly involved in the catalytic destruction of ozone in the lower stratosphere. In a previous work [Bray et al. JQSRT 2011;112:2446], lines positions and intensities of self-perturbed 12CH335Cl and 12CH337Cl have been studied into details for the 3.4 μm spectral region. The present work is focused on measurement and calculation of N2-broadening coefficients of the 12CH335Cl and 12CH337Cl isotopologues. High-resolution Fourier Transform spectra of CH3Cl-N2 mixtures at room-temperature have been recorded between 2800 and 3200 cm-1 at LADIR (using a classical source) and between 47 and 59 cm-1 at SOLEIL (using the synchrotron source on the AILES beamline). 612 mid-infrared transitions of the ν1 band and 86 far-infrared transitions of the pure rotational band have been analyzed using a multispectrum fitting procedure. Average accuracy on the deduced N2-broadening coefficients has been estimated to 5% and 10% in the mid- and far-infrared spectral regions, respectively. The J- and K-rotational dependences of these coefficients have been observed in the mid-infrared region and then a simulation has been performed using an empirical model for 0≤J≤50, K≤9. The 12CH335Cl-N2 line widths for 0≤J≤50 and K≤10 of the ν1 band and for 55≤J≤67 and K≤15 of the pure rotational band have been computed using a semi-classical approach involving exact trajectories and a real symmetric-top geometry of the active molecule. Finally, a global comparison with the experimental and theoretical data existing in the literature has been performed. Similar J- and K-rotational dependences have been appeared while no clear evidence for any vibrational or isotopic dependences have been pointed out.

  17. Electron Density and Temperature Measurement by Stark Broadening in a Cold Argon Arc-Plasma Jet at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiuping; CHENG Cheng; MENG Yuedong

    2009-01-01

    Determination of both the electron density and temperature simultaneously in a cold argon arc-plasma jet by analyzing the Stark broadening of two different emission lines is presented.This method is based on the fact that the Stark broadening of different lines has a different dependence on the electron density and temperature.Therefore,a comparison of two or more line broadenings allows us to diagnose the electron density and temperature simultaneously.In this study we used the first two Balmer series hydrogen lines H_α and H_β for their large broadening width.For this purpose,a small amount of hydrogen was introduced into the discharge gas.The results of the Gigosos-Cardenoso computational model,considering more relevant processes for the hydrogen Balmer lines,is used to process the experimental data.With this method,we obtained reliable electron density and temperature,1.88 ×10 ~(15) cm~(-3 )and 13000 K,respectively.Possible sources of error were also analyzed.

  18. Observation of Doppler broadening in $\\beta$-delayed proton-$\\gamma$ decay

    CERN Document Server

    Schwartz, S B; Bennett, M B; Liddick, S N; Perez-Loureiro, D; Bowe, A; Chen, A A; Chipps, K A; Cooper, N; Irvine, D; McNeice, E; Montes, F; Naqvi, F; Ortez, R; Pain, S D; Pereira, J; Prokop, C; Quaglia, J; Quinn, S J; Sakstrup, J; Santia, M; Shanab, S; Simon, A; Spyrou, A; Thiagalingam, E

    2015-01-01

    Background: The Doppler broadening of $\\gamma$-ray peaks due to nuclear recoil from $\\beta$-delayed nucleon emission can be used to measure the energies of the nucleons. This method has never been tested using $\\beta$-delayed proton emission or applied to a recoil heavier than $A=10$. Purpose: To test and apply this Doppler broadening method using $\\gamma$-ray peaks from the $^{26}$P($\\beta p\\gamma$)$^{25}$Al decay sequence. Methods: A fast beam of $^{26}$P was implanted into a planar Ge detector, which was used as a $^{26}$P $\\beta$-decay trigger. The SeGA array of high-purity Ge detectors was used to detect $\\gamma$ rays from the $^{26}$P($\\beta p\\gamma$)$^{25}$Al decay sequence. Results: Radiative Doppler broadening in $\\beta$-delayed proton-$\\gamma$ decay was observed for the first time. The Doppler broadening analysis method was verified using the 1613 keV $\\gamma$-ray line for which the proton energies were previously known. The 1776 keV $\\gamma$ ray de-exciting the 2720 keV $^{25}$Al level was observed...

  19. The IACOB project: III. New observational clues to understand macroturbulent broadening in massive O- and B-type stars

    CERN Document Server

    Simón-Díaz, S; Castro, N; Herrero, A; Aerts, C; Puls, J; Telting, J; Grassitelli, L

    2016-01-01

    We aim to provide new empirical clues about macroturbulent spectral line broadening in O- and B-type stars to evaluate its physical origin. We use high-resolution spectra of ~430 stars with spectral types in the range O4-B9 (all luminosity classes). We characterize the line-broadening of adequate diagnostic metal lines using a combined FT and GOF technique. We perform a quantitative spectroscopic analysis of the whole sample using automatic tools coupled with a huge grid of FASTWIND models. We also incorporate quantitative information about line asymmetries to our observational description of the characteristics of the line-profiles, and present a comparison of the shape and type of line-profile variability found in a small sample of O stars and B supergiants with still undefined pulsational properties and B main sequence stars with variable line-profiles. We present a homogeneous and statistically significant overview of the (single snapshot) line-broadening properties of stars in the whole O and B star doma...

  20. Linewidth broadening and emission saturation of a resonantly excited quantum dot monitored via an off-resonant cavity mode

    DEFF Research Database (Denmark)

    Ulhaq, A.; Ates, Serkan; Weiler, S.; Ulrich, S.M.; Reitzenstein, S.; Löffler, A.; Höfling, S.; Worschech, L.; Forchel, A.; Michler, P.

    2010-01-01

    We report on the robustness of a detuned mode channel for reading out the relevant s-shell properties of a resonantly excited coupled quantum dot (QD) in a pillar microcavity. The line broadening of the QD s-shell is “monitored” by the mode signal with high conformity to the directly measured QD ...

  1. Shifts and broadenings of barium Rydberg states perturbed by inert gases

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, M; Suji, Z; Bhatia, K; Makdisi, Y; Mathew, J [Department of Physics, Kuwait University, PO Box-5969, 13060-Safat (Kuwait)

    2007-11-14

    Collisional broadening and shift data for even parity states of neutral barium are presented. A two-photon absorption technique is used to populate Rydberg states of nd {sup 1}D{sub 2}, {sup 3}D{sub 2} and {sup 1}S{sub 0} series. High-resolution Ba excitation spectra were measured using a diode detector while scanning the frequency of an excimer pumped dye laser. Inert gases Ar, Kr and Xe were used as perturbers at pressures ranging from 10 mb to 400 mb. Shifts and broadenings of spectral lines were measured as a function of pressure and principal quantum number n. Several perturbations and deviations from expected results are discussed in this paper.

  2. Temporal broadening of pulsed waves propagating through turbulent media

    Institute of Scientific and Technical Information of China (English)

    XU; Zhengwen(许正文); WU; Jian(吴健); HUO; Wenping(霍文平); WU; Zhensen(吴振森)

    2003-01-01

    Pulse signals, propagating through a turbulent medium such as the ionosphere, can be distorted by dispersion and scattering from both the background medium and irregularities embedded in. Thus, the mean square pulse width is changed, and temporal broadening is introduced. We carry out a study on the temporal broadening with theoretical analyses and numerical simulations by using an analytical solution of two-frequency mutual coherence function obtained recently by iteration. As a case of study, pulse broadening is investigated in detail in trans-ionospheric propagation. Results show that most contributions are mainly from the dispersion of the background ionosphere and scattering effects of electron density irregularities in most cases.

  3. Medium Induced Transverse Momentum Broadening in Hard Processes

    CERN Document Server

    Mueller, A H; Xiao, Bo-Wen; Yuan, Feng

    2016-01-01

    Using deep inelastic scattering on a large nucleus as an example, we consider the transverse momentum broadening of partons in hard processes in the presence of medium. We find that one can factorize the vacuum radiation contribution and medium related $P_T$ broadening effects into the Sudakov factor and medium dependent distributions, respectively. Our derivations can be generalized to other hard processes, such as dijet productions, which can be used as a probe to measure the medium $P_T$ broadening effects in heavy ion collisions when Sudakov effects are not overwhelming.

  4. Probing Transverse Momentum Broadening in Heavy Ion Collisions

    CERN Document Server

    Mueller, A H; Xiao, Bo-Wen; Yuan, Feng

    2016-01-01

    We study the dijet azimuthal de-correlation in relativistic heavy ion collisions as an important probe of the transverse momentum broadening effects of a high energy jet traversing the quark-gluon plasma. We take into account both the soft gluon radiation in vacuum associated with the Sudakov logarithms and the jet P_T-broadening effects in the QCD medium. We find that the Sudakov effects are dominant at the LHC, while the medium effects can play an important role at RHIC energies. This explains why the LHC experiments have not yet observed sizable P_T-broadening effects in the measurement of dijet azimuthal correlations in heavy ion collisions. Future investigations at RHIC will provide a unique opportunity to study the P_T-broadening effects and help to pin down the underlying mechanism for jet energy loss in a hot and dense medium.

  5. Calculation of the Doppler broadening function using Fourier analysis

    International Nuclear Information System (INIS)

    An efficient and precise method for calculation of Doppler broadening function is very important to obtain average group microscopic cross sections, self shielding factors, resonance integrals and others reactor physics parameter. In this thesis two different methods for calculation of Doppler broadening function and interference term will be presented. The main method is based on a new integral form for Doppler broadening function ψ(x,ζ) which gives a mathematical interpretation of the approximation proposed by Bethe and Placzek, as the convolution of the Lorentzian function with a Gaussian function. This interpretation besides leading to a new integral form for ψ(x,ζ), enables to obtain a simple analytic solution for the Doppler broadening function. (author)

  6. Self-phase-modulation induced spectral broadening in silicon waveguides

    Science.gov (United States)

    Boyraz, Ozdal; Indukuri, Tejaswi; Jalali, Bahram

    2004-03-01

    The prospect for generating supercontinuum pulses on a silicon chip is studied. Using ~4ps optical pulses with 2.2GW/cm2 peak power, a 2 fold spectral broadening is obtained. Theoretical calculations, that include the effect of two-photon-absorption, indicate up to 5 times spectral broadening is achievable at 10x higher peak powers. Representing a nonlinear loss mechanism at high intensities, TPA limits the maximum optical bandwidth that can be generated.

  7. Broadening of Transverse Momentum of Partons Propagating through a Medium

    OpenAIRE

    Johnson, M. B.; Kopeliovich, B. Z.; Tarasov, A. V.

    2000-01-01

    Broadening of the transverse momentum of a parton propagating through a medium is treated using the color dipole formalism, which has the advantage of being a well developed phenomenology in deep-inelastic scattering and soft processes. Within this approach, nuclear broadening should be treated as color filtering, i.e. absorption of large-size dipoles leading to diminishing (enlarged) transverse separation (momentum). We also present a more intuitive derivation based on the classic scattering...

  8. Stark broadening of the hydrogen resonances Lsub(α) and Lsub(β) in high density plasmas

    International Nuclear Information System (INIS)

    As a concluding remark it can be noted that the foregoing Lsub(α) and Lsub(β) experiments only allowed a limited examination of the theories of the STARK-broadening. Above all the results of the central region of Lsub(α) and Lsub(β) were missing that are necessary for a critical evaluation of the mechanism of the broadening. It was the goal of this work to investigate the STARK-broadening of the resonances Lsub(α) and Lsub(β) especially in the central profile of the region. It was necessary for a performance of the measurement to simultaneously realize the following experimental conditions: the generation of sufficient thin optical line profiles, avoidance of reabsorption in the border zones of the plasma, generation of high electron densities in way that the STARK-part is dominant over the DOPPLER-part. (orig./HT)

  9. How Might Industry Governance Be Broadened To Include Nonproliferation

    International Nuclear Information System (INIS)

    Broadening industry governance to support nonproliferation could provide significant new leverage in preventing the spread/diversion of nuclear, radiological, or dual-use material or technology that could be used in making a nuclear or radiological weapon. Industry is defined broadly to include (1) the nuclear industry, (2) dual-use industries, and (3) radioactive source manufacturers and selected radioactive source-user industries worldwide. This paper describes how industry can be an important first line of defense in detecting and thwarting proliferation, such as an illicit trade network or an insider theft case, by complementing and strengthening existing governmental efforts. For example, the dual-use industry can play a critical role by providing export, import, or security control information that would allow a government or the International Atomic Energy Agency (IAEA) to integrate this information with safeguards, export, import, and physical protection information it has to create a more complete picture of the potential for proliferation. Because industry is closest to users of the goods and technology that could be illicitly diverted throughout the supply chain, industry information can potentially be more timely and accurate than other sources of information. Industry is in an ideal position to help ensure that such illicit activities are detected. This role could be performed more effectively if companies worked together within a particular industry to promote nonproliferation by implementing an industry-wide self-regulation program. Performance measures could be used to ensure their materials and technologies are secure throughout the supply chain and that customers are legitimately using and/or maintaining oversight of these items. Nonproliferation is the overarching driver that industry needs to consider in adopting and implementing a self-regulation approach. A few foreign companies have begun such an approach to date; it is believed that

  10. Laser spectroscopy study of Cr3+ and Mn4+ ions in nanocrystalline MgO: Mechanisms of inhomogeneous broadening and symmetry of centers

    International Nuclear Information System (INIS)

    Sol–gel technology-produced MgO:Cr3+ and MgO:Mn4+,Li+ nanocrystals (particle size ∼5 nm) were studied with laser spectroscopy techniques. The low-temperature fluorescence line narrowing (FLN) experiments were performed for the inhomogeneously broadened R-line of cubic Cr3+ centers. The observed spectra and their dependence on excitation wavelength are significantly different from that reported in literature for the bulk single crystals, and thus demonstrate specific inhomogeneous broadening mechanisms in nanocrystals. The nature of inhomogeneous broadening of spectral lines of impurity ions in nanocrystals is discussed. The site-selective spectroscopy of MgO:0.02%Mn,0.4%Li nanocrystals (Li added for charge compensation) showed that no lines in the emission spectra can be ascribed to Mn4+ centers with cubic symmetry. - Highlights: • The FLN studies of cubic Cr3+ centers in MgO reveal the mechanism of inhomogeneous broadening of spectral lines in nanocrystals. • The crystal lattice distortions caused by the proximity of the surface play a dominant role in inhomogeneous broadening. • The symmetries of surface-related crystal lattice distortions and of the distortions due to point defects are different. • Mn4+ ions do not form cubic centers in MgO:Mn,Li

  11. Accurate modeling of size and strain broadening in the Rietveld refinement: The {open_quotes}double-Voigt{close_quotes} approach

    Energy Technology Data Exchange (ETDEWEB)

    Balzar, D. [Ruder Boskovic Inst., Zagreb (Croatia); Ledbetter, H. [National Inst. of Standards and Technology, Boulder, CO (United States)

    1995-12-31

    In the {open_quotes}double-Voigt{close_quotes} approach, an exact Voigt function describes both size- and strain-broadened profiles. The lattice strain is defined in terms of physically credible mean-square strain averaged over a distance in the diffracting domains. Analysis of Fourier coefficients in a harmonic approximation for strain coefficients leads to the Warren-Averbach method for the separation of size and strain contributions to diffraction line broadening. The model is introduced in the Rietveld refinement program in the following way: Line widths are modeled with only four parameters in the isotropic case. Varied parameters are both surface- and volume-weighted domain sizes and root-mean-square strains averaged over two distances. Refined parameters determine the physically broadened Voigt line profile. Instrumental Voigt line profile parameters are added to obtain the observed (Voigt) line profile. To speed computation, the corresponding pseudo-Voigt function is calculated and used as a fitting function in refinement. This approach allows for both fast computer code and accurate modeling in terms of physically identifiable parameters.

  12. Experimental studies by complementary terahertz techniques and semi-classical calculations of N2- broadening coefficients of CH335Cl

    International Nuclear Information System (INIS)

    Room-temperature N2-broadening coefficients of methyl chloride rotational lines are measured over a large interval of quantum numbers (6≤J≤50, 0≤K≤18) by a submillimeter frequency-multiplication chain (J≤31) and a terahertz photomixing continuous-wave spectrometer (J≥31). In order to check the accuracy of both techniques, the measurements of identical lines are compared for J=31. The pressure broadening coefficients are deduced from line fits using mainly a Voigt profile model. The excellent signal-to-noise ratio of the frequency-multiplication scheme highlights some speed dependence effect on the line shape. Theoretical values of these coefficients are calculated by a semi-classical approach with exact trajectories. An intermolecular potential including atom-atom interactions is used for the first time. It is shown that, contrary to the previous theoretical predictions, the contributions of short-range forces are important for all values of the rotational quantum numbers. Additional testing of modifications required in the semi-classical formalism for a correct application of the cumulant expansion is also performed. It is stated that the use of the cumulant average on the rotational states of the perturbing molecule leads, for high J and small K values, to slightly higher line-broadening coefficients, as expected for the relatively strong interacting CH3Cl-N2 system. The excellent agreement between the theoretical and the experimental results ensures the reliability of these data.

  13. New determination of the core-level life-time broadenings in mercury

    International Nuclear Information System (INIS)

    Highlights: • We report core-level life-time widths for mercury in the gas phase. • Photoelectron spectra for the 4p, 4d, 4f and 5p levels are analyzed. • A Coster–Kronig like CI effect is observed for the 4d3/2 level. - Abstract: Previously recorded and published photoelectron spectroscopic data for mercury in the gas phase has been reanalyzed. The life-time broadenings have been determined for a large number of core levels. It is then seen that a recent detailed derivation of core-level line-widths based on X-ray emission spectroscopy give life-time widths that are generally too large. The 4d3/24d5/2nd Coster–Kronig (CK) transition is also discussed. We find that the additional broadening of the 4d3/2 level for mercury metal is indeed due to a CK decay, in contrast to recent claims. In atomic mercury, however, the CK process in energetically forbidden. In spite of this we find that the 4d3/2 level is broadened also in this case. We propose that this is due to a mixing between the 4d3/2 hole state and discrete 4d5/2nd states

  14. New determination of the core-level life-time broadenings in mercury

    Energy Technology Data Exchange (ETDEWEB)

    Martensson, Nils, E-mail: nils.martensson@fysik.uu.se; Svensson, Svante

    2015-07-15

    Highlights: • We report core-level life-time widths for mercury in the gas phase. • Photoelectron spectra for the 4p, 4d, 4f and 5p levels are analyzed. • A Coster–Kronig like CI effect is observed for the 4d{sub 3/2} level. - Abstract: Previously recorded and published photoelectron spectroscopic data for mercury in the gas phase has been reanalyzed. The life-time broadenings have been determined for a large number of core levels. It is then seen that a recent detailed derivation of core-level line-widths based on X-ray emission spectroscopy give life-time widths that are generally too large. The 4d{sub 3/2}4d{sub 5/2}nd Coster–Kronig (CK) transition is also discussed. We find that the additional broadening of the 4d{sub 3/2} level for mercury metal is indeed due to a CK decay, in contrast to recent claims. In atomic mercury, however, the CK process in energetically forbidden. In spite of this we find that the 4d{sub 3/2} level is broadened also in this case. We propose that this is due to a mixing between the 4d{sub 3/2} hole state and discrete 4d{sub 5/2}nd states.

  15. Toward a Broadband Astro-comb: Effects of Nonlinear Spectral Broadening in Optical Fibers

    CERN Document Server

    Chang, Guoqing; Phillips, David F; Walsworth, Ronald L; Kärtner, Franz X

    2010-01-01

    We propose and analyze a new approach to generate a broadband astro-comb by spectral broadening of a narrowband astro-comb inside a highly nonlinear optical fiber. Numerical modeling shows that cascaded four-wave-mixing dramatically degrades the input comb's side-mode suppression and causes side-mode amplitude asymmetry. These two detrimental effects can systematically shift the center-of-gravity of astro-comb spectral lines as measured by an astrophysical spectrograph with resolution \\approx100,000; and thus lead to wavelength calibration inaccuracy and instability. Our simulations indicate that this performance penalty, as a result of nonlinear spectral broadening, can be compensated by using a filtering cavity configured for double-pass. As an explicit example, we present a design based on an Yb-fiber source comb (with 1 GHz repetition rate) that is filtered by double-passing through a low finesse cavity (finesse = 208), and subsequent spectrally broadened in a 2-cm, SF6-glass photonic crystal fiber. Spann...

  16. Application of Doppler broadening of neutron-induced prompt γ-rays to analytical sciences

    International Nuclear Information System (INIS)

    Activation analysis can measure γ-rays released from excited state of nucleus of nuclear reaction. The energy, sharp and width of γ-ray are not affected by the sample states. However, 7*Li from 10B(n,α)7*Li is an exception. It moderates by interaction with atoms in the course of motion and shows Doppler broadening, of which order depended on the chemical and physical state of sample. The principle of Doppler broadening is explained. The examples of spectra of Doppler broadening of 478 keV-prompt gamma ray are shown. The slowing down constant D (DLSS) of 7*Li is estimated by use of LSS (Lindhart, Scharff and Schiott) theory. As three application examples, boron in the natural cherry leaf, bean and yellow sand were characterized. The line shapes of green leaf and brown leaf were different. The former value was the same as the boric acid solution and the latter the solid boron. D value of yellow sand resembled the value estimated from the composition of aluminosilicate. Accordingly, boron is thought to be exchanged with aluminum. The future problems such as comparison D with DLSS, behavior of 7*Li generated from the smaller size sample with boron than the range and observation of other reaction are discussed. (S.Y.)

  17. Infrared Spectra of N_2-BROADENED 13CH_4 at Titan Atmospheric Temperatures

    Science.gov (United States)

    Smith, M. A. H.; Sung, K.; Brown, L. R.; Crawford, T. J.; Mantz, A. W.; Devi, V. Malathy; Benner, D. Chris

    2010-06-01

    High-resolution spectra of the ν_4 fundamental band of 13CH_4 broadened by N_2 at temperatures relevant to the atmosphere of Titan (80 K to 296 K) have been recorded using new temperature-controlled absorption cells installed in the sample compartment of a Bruker (IFS-125HR) Fourier Transform spectrometer (FTS) at the Jet Propulsion Laboratory (JPL). Details of the cells and spectrometer performance have been discussed in the previous talk. Early analysis of these spectra using multispectrum fitting has determined half widths, pressure-induced shifts, line mixing parameters and their temperature dependences for R-branch transitions from R(0) through R(6). In addition to the initial R(2) study mentioned in the previous talk, the analysis for the other J-manifolds examined in detail whether or not the N_2-broadened half width coefficients follow the simple power-law temperature-dependence over the entire temperature range from 80 K to 296 K. The results are compared with other published measurements of N_2-broadened methane parameters at low temperatures. A. W. Mantz et al., Closed-cycle He-cooled absorption cells designed for a Bruker IFS-125HR: First results between 79 K and 297 K, this session. Research described in this paper was performed at Connecticut College, the College of William and Mary, NASA Langley Research Center and the Jet Propulsion Laboratory, California Institute of Technology, under contracts and cooperative agreements with the National Aeronautics and Space Administration.

  18. Intensities, broadening and narrowing parameters in the ν3 band of methane

    KAUST Repository

    Es-sebbar, Et-touhami

    2014-12-01

    The P-branch of methane\\'s ν3 band is probed to carry out an extensive study of the 2905-2908cm-1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001cm-1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.

  19. Effects of 946-nm thermal shift and broadening on Nd3+:YAG laser performance

    Science.gov (United States)

    Seyed Ebrahim, Pourmand; Ghasem, Rezaei

    2015-12-01

    Spectroscopic properties of flashlamp pumped Nd3+:YAG laser are studied as a function of temperature in a range from -30 °C to 60 °C. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of 4F3/2 → 4I9/2 are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature. The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is, thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state. Project supported by Estahban Branch, Islamic Azad University.

  20. Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic Turbulence and Tangled Molecular Clouds

    CERN Document Server

    Hacar, A; Burkert, A; Goldsmith, P

    2016-01-01

    (Abridged) Many of the observed CO line profiles exhibit broad linewidths that greatly exceed the thermal broadening expected within molecular clouds. These suprathermal CO linewidths are assumed to be originated from the presence of unresolved supersonic motions inside clouds. Typically overlooked in the literature, in this paper we aim to quantify the impact of the opacity broadening effects on the current interpretation of the CO suprathermal line profiles. Without any additional contributions to the gas velocity field, a large fraction of the apparently supersonic (${\\cal M}\\sim$2-3) linewidths measured in both $^{12}$CO and $^{13}$CO (J=1-0) lines can be explained by the saturation of their corresponding sonic-like, optically-thin C$^{18}$O counterparts assuming standard isotopic fractionation. Combined with the presence of multiple components detected in our C$^{18}$O spectra, these opacity effects seem to be also responsible of the highly supersonic linewidths (${\\cal M}>$8-10) detected in the broadest...

  1. Alterations in chemical shifts and exchange broadening upon peptide boronic acid inhibitor binding to α-lytic protease

    International Nuclear Information System (INIS)

    α-Lytic protease, a bacterial serine protease of 198 aminoacids (19800 Da), has been used as a model system for studies of catalytic mechanism, structure-function relationships, and more recently for studies of pro region-assisted protein folding. We have assigned the backbones of the enzyme alone, and of its complex with the tetrahedral transition state mimic N-tert-butyloxycarbonyl-Ala-Pro-boroVal, using double- and triple-resonance 3D NMR spectroscopy on uniformly15N- and 13C/15N-labeled protein.Changes in backbone chemical shifts between the uncomplexed and inhibited form of the protein are correlated with distance from the inhibitor, the displacement of backbone nitrogens, and change in hydrogen bond strength upon inhibitor binding (derived from previously solved crystal structures).A comparison of the solution secondary structure of the uninhibited enzyme with that of the X-ray structure reveals no significant differences.Significant line broadening, indicating intermediate chemical exchange, was observed in many of the active site amides (including three broadened to invisibility), and in a majority of cases the broadening was reversed upon addition of the inhibitor. Implications and possible mechanisms of this line broadening are discussed

  2. Broadening Industry Governance to Include Nonproliferation

    Energy Technology Data Exchange (ETDEWEB)

    Hund, Gretchen; Seward, Amy M.

    2008-11-11

    As industry is the first line of defense in detecting and thwarting illicit trade networks, the engagement of the private sector is critical to any government effort to strengthen existing mechanisms to protect goods and services throughout the supply chain. This study builds on previous PNNL work to continue to evaluate means for greater industry engagement to complement and strengthen existing governmental efforts to detect and stem the trade of illicit goods and to protect and secure goods that could be used in making a weapon of mass destruction. Specifically, the study evaluates the concept of Industry Self Regulation, defined as a systematic voluntary program undertaken by an industry or by individual companies to anticipate, implement, supplement, or substitute for regulatory requirements in a given field, generally through the adoption of best practices. Through a series of interviews with companies with a past history of non-compliance, trade associations and NGOs, the authors identify gaps in the existing regulatory infrastructure, drivers for a self regulation approach and the form such an approach might take, as well as obstacles to be overcome. The authors conclude that it is at the intersection of industry, government, and security that—through collaborative means—the effectiveness of the international nonproliferation system—can be most effectively strengthened to the mutual benefit of both government and the private sector. Industry has a critical stake in the success of this regime, and has the potential to act as an integrating force that brings together the existing mechanisms of the global nonproliferation regime: export controls, physical protection, and safeguards. The authors conclude that industry compliance is not enough; rather, nonproliferation must become a central tenant of a company’s corporate culture and be viewed as an integral component of corporate social responsibility (CSR).

  3. Measured Stark widths of several Ni II spectral lines

    International Nuclear Information System (INIS)

    The Stark broadening parameters of 17 lines of Ni II have been measured in a plasma produced by ablation of an Al-Ni alloy with a Nd:YAG laser. The broadening parameters were obtained with the target placed in molecular argon at 6 Torr, which provides appropriate measurement conditions. A Boltzmann plot was used to obtain the plasma temperature (16 500 ± 2100 K) and published values of the Stark broadening in Al II to obtain the electron density ((1.07 ± 0.10)1017cm-3); with these values, the plasma composition was determined by means of the Saha equation. The local thermodynamic equilibrium condition was checked. Contributions to broadening arising from a mechanism different from the Stark broadening as well as self-absorption influence were estimated for every studied line. A comparison was made with previous experimental values and recent theoretical estimates of the Stark broadening where possible

  4. Broadening of Transverse Momentum of Partons Propagating through a Medium

    CERN Document Server

    Johnson, M B; Tarasov, A V

    2001-01-01

    Broadening of the transverse momentum of a parton propagating through a medium is treated using the color dipole formalism, which has the advantage of being a well developed phenomenology in deep-inelastic scattering and soft processes. Within this approach, nuclear broadening should be treated as color filtering, i.e. absorption of large-size dipoles leading to diminishing (enlarged) transverse separation (momentum). We also present a more intuitive derivation based on the classic scattering theory of Moli\\`ere. This derivation helps to understand the origin of the dipole cross section, part of which comes from attenuation of the quark, while another part is due to multiple interactions of the quark. It also demonstrates that the lowest-order rescattering term provides an A-dependence very different from the generally accepted A^{1/3} behavior. The effect of broadening increases with energy, and we evaluate it using different phenomenological models for the unintegrated gluon density. Although the process is...

  5. Optical coherent control in semiconductors: Fringe contrast and inhomogeneous broadening

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

    2001-01-01

    Optical coherent control experiments in semiconductors reveal how inhomogeneous broadening must be taken into account in contrast to previous coherent control experiments in atomic and molecular systems. With spectral resolution elf the coherent control signal, the optical phases involved...... in the interplay between the homogeneous and inhomogeneous broadenings are measured. Based on these experiments, a coherent control model describing the optical fringe contrast using different detection schemes, such as photoluminescence or four-wave mixing, is established. Significant spectral modulation...... is observed in the four-wave mixing spectra as a function of phase-delay representing coherent control in the spectral domain. The spectral phase change of this modulation provides a spectroscopic tool to analyze contributions of inhomogeneous broadening to electronic resonances in semiconductor structures....

  6. Combustion technology overview. [the use of broadened property aircraft fuels

    Science.gov (United States)

    Niedzwiecki, R. W.

    1980-01-01

    An overview of combustor technology developments required for use of broadened property fuels in jet aircraft is presented. The intent of current investigations is to determine the extent to which fuel properties can be varied, to obtain a data base of combustion - fuel quality effects, and to determine the trade-offs associated with broadened property fuels. Subcomponents of in-service combustors such as fuel injectors and liners, as well as air distributions and stoichiometry, are being altered to determine the extent to which fuel flexibility can be extended. Finally, very advanced technology consisting of new combustor concepts is being evolved to optimize the fuel flexibility of gas turbine combustors.

  7. Multigroup Free-atom Doppler-broadening Approximation. Theory

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-06

    Multigroup cross sections at a one target temperature can be Doppler-broadened to multigroup cross sections at a higher target temperature by matrix multiplication if the group structure suf- ficiently resolves the original temperature continuous energy cross section. Matrix elements are the higher temperature group weighted averages of the integral over the lower temperature group boundaries of the free-atom Doppler-broadening kernel. The results match theory for constant and 1/v multigroup cross sections at 618 lanl group structure resolution.

  8. Multigroup Free-atom Doppler-broadening Approximation. Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-06

    The multigroup energy Doppler-broadening approximation agrees with continuous energy Dopplerbroadening generally to within ten percent for the total cross sections of 1H, 56Fe, and 235U at 250 lanl. Although this is probably not good enough for broadening from room temperature through the entire temperature range in production use, it is better than any interpolation scheme between temperatures proposed to date, and may be good enough for extrapolation from high temperatures. The method deserves further study since additional improvements are possible.

  9. Study of peak broadening effect in floor time histories

    International Nuclear Information System (INIS)

    Seismic design of secondary systems such components and piping is usually carried out by using the floor motions at their support points. These floor motions can be in the form of Floor Response Spectra (FRS) or the Floor Time Histories (FTH). In order to account for the various uncertainties in generating these floor motions, these motions should be peak broadened and smoothened as per the regulatory codes. Presented here in this paper is the methodology to account for such peak broadening effect in the FTH. Results of this study have been compared with the FRS approach and various important conclusions have been arrived at based on the study

  10. Measurements of Methane at 7.5 μm Broadened by Nitrogen at Low Temperatures

    Science.gov (United States)

    Smith, Mary-Ann H.; Mantz, A. W.; Sung, K.; Brown, L. R.; Crawford, T. J.; Malathy Devi, V.; Benner, D. Chris

    2010-10-01

    Since the ν4 band system of methane (CH4) at 7.5 µm appears prominently in infrared spectra of Titan's atmosphere, we are conducting laboratory studies to examine the temperature-dependence of infrared transitions of CH4 broadened by N2 in this spectral region. Spectra of methane-nitrogen mixtures at temperatures from 79 to 297 K were obtained at 0.006 cm-1 resolution (resolving power = 2x105) using the Bruker IFS 125HR Fourier transform spectrometer at the Jet Propulsion Laboratory with new temperature-controlled gas cells designed specifically to fit in the spectrometer's sample compartment. Details of the cells and spectrometer performance [1] are described in an adjacent poster by Sung et al. A multispectrum nonlinear least squares technique [2] is used to fit selected intervals of 9 or more spectra simultaneously to obtain the temperature dependences of line broadening, pressure-induced shift and line mixing parameters. Results for 13CH4 at 80 to 297 K are discussed relative to our previous high-resolution studies of air- and self-broadened 12CH4 and 13CH4 [3-5] at terrestrial atmospheric temperatures (210 to 314 K). This research is supported by NASA's Planetary Atmospheres Program. 1. K. Sung et al., J. Mol. Spectrosc. (2010) doi:10.1016/j.jms.2010.05.004. 2. D. Chris Benner et al., J. Quant. Spectrosc. Radiat. Transfer 53 (1995) 705-721. 3. M. A. H. Smith et al., J. Quant. Spectrosc. Radiat. Transfer 110 (2009) 639-653. 4. M. A. H. Smith et al., J. Quant. Spectrosc. Radiat. Transfer 111 (2010) 1152-1166. 5. M. A. H. Smith et al., J. Quant. Spectrosc. Radiat. Transfer (2010) submitted.

  11. Doppler Shifts and Broadening and the Structure of the X-ray Emission from Algol

    CERN Document Server

    Chung, S M; Kashyap, V L; Lin, L W; Ratzlaff, P W; Chung, Sun Mi; Drake, Jeremy J.; Kashyap, Vinay L.; Lin, Li Wei; Ratzlaff, Peter W.

    2004-01-01

    In a study of Chandra High Energy Transmission Grating spectra of Algol, we clearly detect Doppler shifts caused by the orbital motion of Algol B. These data provide the first definitive proof that the X-ray emission of Algol is dominated by the secondary, in concordance with expectations that Algol A (B8) is X-ray dark. The measured Doppler shifts are slightly smaller than expected, implying an effective orbital radius of about 10 Rsolar, instead of 11.5 Rsolar for the Algol B center of mass. This could be caused by a small contribution of X-ray flux from Algol A (10-15%), possibly through accretion. The more likely explanation is an asymmetric corona biased toward the system center of mass by the tidal distortion of the surface of Algol B. Analysis of the strongest lines indicates excess line broadening of ~150 km/s above that expected from thermal motion and surface rotation. Possible explanations include turbulence, flows or explosive events, or rotational broadening from a radially extended corona. We fa...

  12. Laser spectroscopy of multi-level doppler broadened atomic system

    International Nuclear Information System (INIS)

    Doppler broadened atomic vapor system can be easily prepared for spectroscopy study than an atomic beam system can be. Vapor cell and hollow cathode discharge lamps are widely used in the experiment. The possibility for observing the trapped state in a Doppler broadened Λ system was examined and confirmed by our early experiment where counter-propagating laser beams are used. For the measurement of the hyperfine structure constants of high-lying levels of heavy elements, we compared the co-propagating and counter-propagating beams in a Doppler broadened ladder systems. It was shown that the counter-propagating beams give a stronger and narrower signal than that from the co-propagating beams. Our treatment also considers the power broadening of the transition. For some photo-ionization experiments, it is necessary to pump two thermally populated levels simultaneously to the higher level and then to the auto-ionizing levels. A technique is proposed to avoid the trapped state and to increase the ionization efficiency.

  13. Broadening the concept of international entrepreneurship: 'Consumers as international entrepreneurs'

    NARCIS (Netherlands)

    Y. Chandra; N. Coviello

    2010-01-01

    We integrate theories from international business, entrepreneurship, innovation, marketing and network economics to develop a four-part typology of ‘consumers as international entrepreneurs’. This broadens the concept of international entrepreneurship and complements the firm-level focus customary i

  14. On-The-Fly neutron Doppler broadening in MCNP

    International Nuclear Information System (INIS)

    Multi-physics calculations may involve coupling continuous-energy Monte Carlo neutronics codes to CFD codes that provide many thousands or even millions of region temperatures. The traditional Monte Carlo approach - using pre-calculated Doppler broadened nuclear cross-sections - is not feasible for these large multi-physics problems. Instead, an On-the-Fly (OTF) Doppler broadening methodology is required, whereby neutron cross-sections are broadened during the Monte Carlo transport. To this end, we have developed a methodology for MCNP to provide OTF broadening based on cell temperatures during neutron tracking. The method enables the use of many thousands or more temperatures in MCNP Monte Carlo calculations for multi-physics applications, significantly advancing the state-of-the-art by permitting the solution of problems that were not previously possible with continuous-energy Monte Carlo codes. A production library with an extended set of isotopes has been developed for use with MCNP6. Calculations of test problems with MCNP6 and the new library demonstrate the accuracy and effectiveness of the OTF approach. (authors)

  15. On the Fly Doppler Broadening Using Multipole Representation

    International Nuclear Information System (INIS)

    On the Fly Doppler broadening is the technique to avoid pre-generation of the microscopic cross section, in other words, reduce the amount of storage. Currently, there are different types of formalisms used by NJOY code to generate reaction cross section and accomplish its Doppler broadening. Single-Level Breit-Wigner (SLBW) formalism is limited to well-separated resonances, in other words, it does not consider interference between energy levels. Multi-Level Breit- Wigner formalism (MLBW) was tested as the candidate for the cross section generation in the Monte Carlo code, which is under development in UNIST. According to the results, MLBW method requires huge amount of computational time to produce cross section at certain energy point. Reich-Moore (RM) technique can generate only 0K cross section, which means that it cannot produce broaden cross section directly from resonance parameters. The first step was to convert resonance parameters given in nuclear data file into multipoles. MPR shows very high potential to be used as the formalism in the on-the-fly Doppler broadening module of MCS. One of the main reasons is that comparison of the time cost shown in Table IV supports application of multipole representation

  16. Doppler-broadening of gamma rays following muon capture search for scalar coupling

    CERN Document Server

    Shitov, Y; Briançon, C; Brudanin, V; Deutsch, J; Filipova, T; Petitjean, C; Prieels, R; Siiskonen, T; Suhonen, J; Vylov, T D; Wiaux, V; Yutlandov, I A; Zaparov, S

    2002-01-01

    A precision measurement of the 277 keV gamma ray produced by capturing muons in gaseous oxygen was performed using high-resolution HPGe detectors. The Doppler-broadened shape of this line is sensitive to the possible admixture into muon capture of genuine scalar interaction. This experiment complements, in the muon sector, in principle, similar ones undertaken recently in nuclear beta decay. Using a procedure discussed in earlier papers, a fit to the experimental line-shape allowed us to obtain for the recoil-gamma correlation coefficient the value of a sup 1 sub 2 =0.096+-0.041 (95% CL). The available evaluations of the contributing nuclear matrix elements, performed in the impulse approximation in the absence of scalar interaction, produce correlation coefficients in disagreement with our result. These evaluations are independent of the induced pseudoscalar coupling and so of the validity of the PCAC hypothesis, but their reliability and model dependence remain to be investigated.

  17. On systematic errors in spectral line parameters retrieved with the Voigt line profile

    Science.gov (United States)

    Kochanov, V. P.

    2012-08-01

    Systematic errors inherent in the Voigt line profile are analyzed. Molecular spectrum processing with the Voigt profile is shown to underestimate line intensities by 1-4%, with the errors in line positions being 0.0005 cm-1 and the decrease in pressure broadening coefficients varying from 5% to 55%.

  18. Peak broadening in paper chromatography and related techniques : III. Peak broadening in thin-layer chromatography on cellulose powder

    NARCIS (Netherlands)

    Ligny, C.L. de; Remijnse, A.G.

    1968-01-01

    The mechanism of peak broadening in thin-layer chromatography on cellulose powder was investigated by comparing the peak widths obtained in chromatography with those caused only by diffusion in the cellulose powder, for a set of amino acids of widely differing RF values and six kinds of cellulose po

  19. Spectral Line Shapes in Plasmas and Gases

    International Nuclear Information System (INIS)

    The subject of spectral line shapes (SLS), a.k.a. spectral line broadening, which embraces both shapes and shifts of spectral lines, is of both fundamental and practical importance. On the fundamental side, the study of the spectral line profiles reveals the underlying atomic and molecular interactions. On the practical side, the spectral line profiles are employed as powerful diagnostic tools for various media, such as neutral gases, technological gas discharges, magnetically confined plasmas for fusion, laser- and Z-pinch-produced plasmas (for fusion and other purposes), astrophysical plasmas (most importantly, solar plasmas), and planetary atmospheres. The research area covered by this special issue includes both the SLS dominated by various electric fields (including electron and ion micro fields in strongly ionized plasmas) and the SLS controlled by neutral particles. In the physical slang, the former is called plasma broadening while the latter is called neutral broadening (of course, the results of neutral broadening apply also to the spectral line broadening in neutral gases)

  20. Suppression of power-broadening in strong-coupling photoassociation in the presence of a Feshbach resonance

    CERN Document Server

    Deb, Bimalendu

    2009-01-01

    Photoassociation (PA) spectrum in the presence of a magnetic Feshbach resonance is analyzed. Nonperturbative solution of the problem yields analytical expressions for PA linewidth and shift which are applicable for arbitrary PA laser intensity and magnetic field tuning of Feshbach Resonance. We show that by tuning magnetic field close to Fano minimum, it is possible to suppress power broadening at increased laser intensities. This occurs due to quantum interference of PA transitions from unperturbed and perturbed continuum. Line narrowing at high laser intensities is accompanied by large spectral shifts. We briefly discuss important consequences of line narrowing in cold collisions.

  1. Resolution-enhancement of broadened spectra of the UV-light and thermal treated alanine free radicals

    International Nuclear Information System (INIS)

    Two methods for resolution-enhancing broadened spectra were analyzed. One method was used to treat ESR spectra of the γ-ray induced alanine free radicals and to study the effect when they are subjected to UV-light and heat. Spectral differences are obvious between these treatments. From a combined UV-light and heat treatment of these free radicals, some ESR lines disappear while five broad lines still remain. These spectral differences may clearly suggest the existence of two or more free radical species in γ-ray irradiated alanine that can be predicted at room temperature

  2. Dependence of inhomogeneous vibrational linewidth broadening on attractive forces from local liquid number densities

    International Nuclear Information System (INIS)

    The dependence of inhomogeneous vibrational linewidth broadening on attractive forces form slowly varying local liquid number densities is examined. The recently developed Schweizer--Chandler theory of vibrational dephasing is used to compute absolute inhomogeneous broadening linewidths. The computed linewidths are compared to measured inhomogeneous broadening linewidths determined using picosecond vibrational dephasing experiments. There is a similarity between correlations of the Schweizer--Chandler and George--Auweter--Harris predicted inhomogeneous broadening linewidths and the measured inhomogeneous broadening linewidths. For the methyl stretches under investigation, this correspondence suggests that the width of the number density distribution in the liquid determines the relative inhomogeneous broadening magnitudes

  3. Positive emotions and the social broadening effects of Barack Obama.

    Science.gov (United States)

    Ong, Anthony D; Burrow, Anthony L; Fuller-Rowell, Thomas E

    2012-10-01

    Past experiments have demonstrated that the cognitive broadening produced by positive emotions may extend to social contexts. Building on this evidence, we hypothesized that positive emotions triggered by thinking about Barack Obama may broaden and expand people's sense of self to include others. Results from an expressive-writing study demonstrated that African American college students prompted to write about Obama immediately prior to and after the 2008 presidential election used more plural self-references, fewer other-references, and more social references. Mediation analyses revealed that writing about Obama increased positive emotions, which in turn increased the likelihood that people thought in terms of more-inclusive superordinate categories (we and us rather than they and them). Implications of these findings for the role of positive emotions in perspective-taking and intergroup relations are considered. PMID:22905966

  4. Stability analysis for bad cavity lasers with inhomogeneously broadened gain

    CERN Document Server

    Kazakov, Georgy A

    2016-01-01

    Bad cavity lasers are experiencing renewed interest in the context of active optical frequency standards, due to their enhanced robustness against fluctuations of the laser cavity. The gain medium would consist of narrow-linewidth atoms, either trapped inside the cavity or intersecting the cavity mode dynamically. A finite velocity distribution, atomic interactions, or interactions of realistic multilevel atoms with external field leads to an inhomogeneous broadening of the atomic gain profile. This can bring the bad cavity laser to operate in unstable regimes characterized by complex temporal patterns of the field amplitude. We present a new and efficient method for the stability analysis of bad cavity lasers with inhomogeneously broadened gain. We apply this method to identify the steady-state solutions for the metrology-relevant case of spin-1/2 atoms interacting with an external magnetic field.

  5. Momentum broadening in unstable quark-gluon plasma

    OpenAIRE

    Carrington, M. E.; Mrówczyński, St.; Schenke, B.

    2016-01-01

    Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the ra...

  6. Impact of Broadening Definitions of Anorexia Nervosa on Sample Characteristics

    OpenAIRE

    Dellava, Jocilyn E.; Thornton, Laura M.; Lichtenstein, Paul; Pedersen, Nancy L; Bulik, Cynthia M

    2010-01-01

    Practical limitations and sample size considerations often lead to broadening of diagnostic criteria for anorexia nervosa (AN) in research. The current study sought to elucidate the effects of this practice on resultant sample characteristics in terms of eating disorder behaviors, psychiatric comorbidities, temperament and personality characteristics, and heritability point estimates. Three definitions of AN were created: meeting all Diagnostic and Statistical Manual of Mental Disorders-IV (D...

  7. Positive mood broadens visual attention to positive stimuli

    OpenAIRE

    Wadlinger, Heather A.; Isaacowitz, Derek M.

    2006-01-01

    In an attempt to investigate the impact of positive emotions on visual attention within the context of Fredrickson's (1998) broaden-and-build model, eye tracking was used in two studies to measure visual attentional preferences of college students (n=58, n=26) to emotional pictures. Half of each sample experienced induced positive mood immediately before viewing slides of three similarly-valenced images, in varying central-peripheral arrays. Attentional breadth was determined by measuring the...

  8. Broadening the diagnosis of bipolar disorder: benefits vs. risks

    OpenAIRE

    Strakowski, Stephen M.; Fleck, David E.; MAJ, MARIO

    2011-01-01

    There is considerable debate over whether bipolar and related disorders that share common signs and symptoms, but are currently defined as distinct clinical entities in DSM-IV and ICD-10, may be better characterized as falling within a more broadly defined “bipolar spectrum”. With a spectrum view in mind, the possibility of broadening the diagnosis of bipolar disorder has been proposed. This paper discusses some of the rationale for an expanded diagnostic scheme from both cl...

  9. VAT Base Broadening, Self Supply, and The Informal Sector

    OpenAIRE

    John Piggott; John Whalley

    1998-01-01

    We develop a general equilibrium tax model to evaluate the impacts of equal yield base broadening in indirect taxes from high rate narrow based (typically manufactures) taxes to broad based taxes (including services) such as a VAT. We capture differences in choice of mode of supply between market goods, such as manufactures, which cannot be supplied other than through the market, and self-suppliable services and informal sector supplied products. Using this formulation, we are able to provide...

  10. On the process dependent nuclear $k_\\perp$ broadening effect

    OpenAIRE

    Schäfer, Andreas; Zhou, Jian

    2013-01-01

    We study the process dependent nuclear $k_\\perp$ broadening effect by employing the transverse momentum dependent(TMD) factorization approach in combination with the Mclerran-Venugopalan(MV) model. More specifically, we investigate how the parton transverse momentum distributions are affected by the process dependent gauge links in cold nuclear matter. In particular, our analysis also applies to the polarized cases including the nuclear quark Boer-Mulders function and the linearly polarized g...

  11. Fundamental edge broadening effects during focused electron beam induced nanosynthesis

    OpenAIRE

    Roland Schmied; Fowlkes, Jason D.; Robert Winkler; Rack, Phillip D; Harald Plank

    2015-01-01

    The present study explores lateral broadening effects of 3D structures fabricated through focused electron beam induced deposition using MeCpPt(IV)Me3 precursor. In particular, the scaling behavior of proximity effects as a function of the primary electron energy and the deposit height is investigated through experiments and validated through simulations. Correlated Kelvin force microscopy and conductive atomic force microscopy measurements identified conductive and non-conductive proximity r...

  12. Modeling Solvent Broadening on the Vibronic Spectra of a Series of Coumarin Dyes. From Implicit to Explicit Solvent Models.

    Science.gov (United States)

    Cerezo, Javier; Avila Ferrer, Francisco J; Prampolini, Giacomo; Santoro, Fabrizio

    2015-12-01

    We present a protocol to estimate the solvent-induced broadening of electronic spectra based on a model that explicitly takes into account the environment embedding the solute. Starting from a classical approximation of the solvent contribution to the spectrum, the broadening arises from the spread of the excitation energies due to the fluctuation of the solvent coordinates, and it is represented as a Gaussian line shape that convolutes the vibronic spectrum of the solute. The latter is computed in harmonic approximation at room temperature with a time-dependent approach. The proposed protocol for the computation of spectral broadening exploits molecular dynamics (MD) simulations performed on the solute-solvent system, keeping the solute degrees of freedom frozen, followed by the computation of the excitation properties with a quantum mechanics/molecular mechanics (QM/MM) approach. The factors that might influence each step of the protocol are analyzed in detail, including the selection of the empirical force field (FF) adopted in the MD simulations and the QM/MM partition of the system to compute the excitation energies. The procedure is applied to a family of coumarin dyes, and the results are compared with experiments and with the predictions of a very recent work (Cerezo et al., Phys. Chem. Chem. Phys. 2015, 17, 11401-11411), where an implicit model was adopted for the solvent. The final spectra of the considered coumarins were obtained without including ad hoc phenomenological parameters and indicate that the broadenings computed with explicit and implicit models both follow the experimental trend, increasing as the polarity change from the initial to the final state increases. More in detail, the implicit model provides larger estimations of the broadening that are closer to the experimental evidence, while explicit models appear to better capture relative differences arising from different solvents or different solutes. Possible inaccuracies of the adopted

  13. Brillouin resonance broadening due to structural variations in nanoscale waveguides

    Science.gov (United States)

    Wolff, C.; Van Laer, R.; Steel, M. J.; Eggleton, B. J.; Poulton, C. G.

    2016-02-01

    We study the impact of structural variations (that is slowly varying geometry aberrations and internal strain fields) on the width and shape of the stimulated Brillouin scattering (SBS) resonance in nanoscale waveguides. We find that they lead to an inhomogeneous resonance broadening through two distinct mechanisms: firstly, the acoustic frequency is directly influenced via mechanical nonlinearities; secondly, the optical wave numbers are influenced via the opto-mechanical nonlinearity leading to an additional acoustic frequency shift via the phase-matching condition. We find that this second mechanism is proportional to the opto-mechanical coupling and, hence, related to the SBS-gain itself. It is absent in intra-mode forward SBS, while it plays a significant role in backward scattering. In backward SBS increasing the opto-acoustic overlap beyond a threshold defined by the fabrication tolerances will therefore no longer yield the expected quadratic increase in overall Stokes amplification. Finally, we illustrate in a numerical example that in backward SBS and inter-mode forward SBS the existence of two broadening mechanisms with opposite sign also opens the possibility to compensate the effect of geometry-induced broadening. Our results can be transferred to other micro- and nano-structured waveguide geometries such as photonic crystal fibres.

  14. Dispersive hole growth kinetics and fluence broadening of the zero-phonon hole of impurities in amorphous hosts

    International Nuclear Information System (INIS)

    A detailed treatment of the relationship between the dispersive growth kinetics of the zero-phonon hole (ZPH) of an impurity molecule in an amorphous host and burn fluence broadening of the ZPH is presented. Focus is on non-photochemical hole burning (NPHB). The equation used for simulations accounts for dispersion due to a distribution of tunneling parameters (λ-distribution), the angle between the laser polarization and the transition dipole (α-distribution), and off-resonant absorption of the zero-phonon line (ω-distribution). Two cases are considered: burned laser linewidth narrow relative to the homogeneous width of the zero-phonon line; and the reverse situation. Results are presented for two model systems whose parameter values are similar to those of aluminum phthalocyanine tetrasulphonate (APT) in hyperquenched glassy water and in hyperquenched glassy ethanol. For comparison, results are presented for the case where the hole growth kinetics are non-dispersive (single-exponential). It is found that at the early stage of burning fluence broadening is considerably more severe for a dispersive system than for a non-dispersive system. A straightforward explanation for this is given. The results are compared with those of earlier works on dispersive hole growth kinetics and fluence broadening. The results reveal the types of experiment needed to understand the aforementioned relationship, a requirement for determination of the homogeneous width of the ZPH that reflects the dynamics of the system

  15. The rotational broadening of V395 Car - implications on compact object's mass

    CERN Document Server

    Shahbaz, T

    2007-01-01

    CONTEXT: The masses previously obtained for the X-ray binary 2S0921-630 inferred a compact object that was either a high-mass neutron star or low-mass black-hole, but used a previously published value for the rotational broadening (vsini) with large uncertainties. AIMS: We aim to determine an accurate mass for the compact object through an improved measurement of the secondary star's projected equatorial rotational velocity. METHODS: We have used UVES echelle spectroscopy to determine the vsini of the secondary star (V395 Car) in the low-mass X-ray binary 2S0921-630 by comparison to an artificially broadened spectral-type template star. In addition, we have also measured vsini from a single high signal-to-noise ratio absorption line profile calculated using the method of Least-Squares Deconvolution (LSD). RESULTS: We determine vsini to lie between 31.3+/-0.5km/s to 34.7+/-0.5km/s (assuming zero and continuum limb darkening, respectively) in disagreement with revious results based on intermediate resolution sp...

  16. High frequency VLBI observations of the scatter broadened quasar B2005+403

    CERN Document Server

    Gabanyi, K E; Britzen, S; Krichbaum, T P; Ros, E; Witzel, A; Zensus, J A

    2006-01-01

    The quasar B2005+403 located behind the Cygnus region, is a suitable object for studying the interplay between propagation effects, which are extrinsic to the source and source intrinsic variability. On the basis of VLBI experiments performed at 1.6, 5, 8, 15, 22, and 43GHz between 1992-2003 and parallel multi-frequency monitoring of the total flux density, we investigated the variability of total flux density and source structure. Below 8 GHz, the point-like VLBI source is affected by scatter-broadening of the turbulent interstellar medium, which is located along the line of sight and likely associated with the Cygnus region. We present and discuss the measured frequency dependence of the source size, which shows a power-law with slope of -1.91+/-0.05. From the measured scattering angle at 1GHz of 77.1+/-4.0mas a SM=0.43+/-0.04 m^{-20/3} kpc is derived, consistent with the general properties of the ISM in this direction. The decreasing effect of angular broadening towards higher frequencies allows to study t...

  17. Characterization of ion-irradiated ODS Fe–Cr alloys by doppler broadening spectroscopy using a positron beam

    Energy Technology Data Exchange (ETDEWEB)

    Parente, P.; Leguey, T. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Castro, V. de, E-mail: vanessa.decastro@uc3m.es [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain); Gigl, T.; Reiner, M.; Hugenschmidt, C. [FRM II and Physics Department, Technische Universität München, 85747 Garching (Germany); Pareja, R. [Departamento de Física and IAAB, Universidad Carlos III de Madrid, 28911 Leganés (Spain)

    2015-09-15

    The damage profile of oxide dispersion strengthened steels after single-, or simultaneous triple-ion irradiation at different conditions has been characterized using a low energy positron beam in order to provide information on microstructural changes induced by irradiation. Doppler broadening and coincident Doppler broadening measurements of the positron annihilation line have been performed on different Fe–Cr–(W,Ti) alloys reinforced with Y{sub 2}O{sub 3}, to identify the nature and stability of irradiation-induced open-volume defects and their possible association with the oxide nanoparticles. It was found that irradiation induced vacancy clusters are associated with Cr atoms. The results are of highest interest for modeling the damage induced by 14 MeV neutrons in reduced activation Fe–Cr alloys relevant for fusion devices.

  18. Temperature dependences of N2-broadening and shift coefficients in the ν6 perpendicular band of 12CH3D

    International Nuclear Information System (INIS)

    The temperature-dependences of line broadening and shift parameters for many 12CH3D transitions have been determined using six high-resolution, high signal-to-noise ratio, room-temperature CH3D (98% purity) and CH3D-N2 spectra recorded with 25 cm path length ( at 0.01 cm−1 unapodized resolution) using the McMath−Pierce FTS located on Kitt Peak, Arizona, and 17 additional high quality, pure CH3D (99% purity) and CH3D-N2 spectra recorded between 79 and 296 K with the 20.38 cm path coolable cell (at 0.0056 cm−1 unapodized resolution) with the Bruker 125HR FTS at the Jet Propulsion Laboratory (JPL), Pasadena, California. The spectra have been fitted simultaneously applying a multispectrum nonlinear least-squares technique. In the analysis, the Lorentzian N2-broadened half-width coefficients and the corresponding pressure-shift coefficients as well as their temperature dependences are extracted for about 400 transitions (0≤J″≤19, K″≤16) in the perpendicular (ΔK=±1) ν6 band. At 296 K, the measured N2-broadened half-width coefficients range from 0.0209 to 0.0782 cm−1 atm−1 whereas the majority of the associated N2-induced shift coefficients are negative, and the values are between -0.016 and 0.005 cm−1 atm−1. The temperature dependence exponents for N2-broadened half-widths range between 0.264 and 0.924, whereas the temperature dependence coefficients for N2-induced shifts are between 0 and 0.00011 cm−1 atm−1 K−1. The N2-broadened half-width coefficients have been also calculated using a semi-classical approach 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. The role of the various high-order multipoles in the line-broadening at low, middle and high values of the rotational quantum number J″ has been investigated and the main features of the K-dependences analyzed. The calculations performed for

  19. On the Application of Stark Broadening Data Determined with a Semiclassical Perturbation Approach

    Directory of Open Access Journals (Sweden)

    Milan S. Dimitrijević

    2014-08-01

    Full Text Available The significance of Stark broadening data for problems in astrophysics, physics, as well as for technological plasmas is discussed and applications of Stark broadening parameters calculated using a semiclassical perturbation method are analyzed.

  20. Smile to see the forest: Facially expressed positive emotions broaden cognition

    OpenAIRE

    Johnson, Kareem J.; Waugh, Christian E.; Fredrickson, Barbara L.

    2010-01-01

    The broaden hypothesis, part of Fredrickson’s (1998, 2001) broaden-and-build theory, proposes that positive emotions lead to broadened cognitive states. Here, we present evidence that cognitive broadening can be produced by frequent facial expressions of positive emotion. Additionally, we present a novel method of using facial electromyography (EMG) to discriminate between Duchenne (genuine) and non-Duchenne (non-genuine) smiles. Across experiments, Duchenne smiles occurred more frequently du...

  1. Infrared spectroscopy at high temperature : N2- and O2-broadening coefficients in the ν4 band of CH4

    Science.gov (United States)

    Fissiaux, Laurent; Populaire, Jean-Claude; Blanquet, Ghislain; Lepère, Muriel

    2015-11-01

    In the present work, we have developed a high-temperature absorption cell for infrared spectroscopy. This absorption cell can contain gases of the room temperature up to 650 K without temperature gradient. The construction of the cell and its technical features are described in detail in this paper. In order to demonstrate the feasibility and the interest of the cell, we have measured the N2-, O2- and air-broadening coefficients of, respectively, six and three absorption lines in the ν4 band of methane at four temperatures (350, 425, 500, 575 K). The measurements of these coefficients was realized with a tunable diode-laser spectrometer. The line parameters were obtained by fitting to the experimental profile the Voigt line shape and the Rautian and Galatry models taking into account the collisional narrowing. For these lines, the n parameter of the temperature dependence has been determined.

  2. A Doppler-broadening facility for positron spin relaxation (e{sup +}SR) experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gessmann, Th.; Harmat, P.; Major, J.; Seeger, A. [Max-Planck-Institut fuer Metallforschung, Institut fuer Physik, Stuttgart, Stuttgart (Germany)

    1997-05-14

    A set-up is described for the determination of the spin polarization of positrons emitted from radioactive sources that makes use of the dependence of the Doppler broadening of the 511 keV annihilation photon line on the strength and direction (with regard to the spin polarization) of an applied magnetic field. In the so-called e{sup +}SR (positron spin relaxation) technique the sample to be investigated is part of the e{sup +}-spin polarimeter. Its application to the investigation of positronium formation in condensed matter is illustrated using crystalline quartz as an example. The method earlier applied to the positron annihilation in magnetized ferromagnets is now transferred to the detection of positronium (Ps) in condensed matter. This new approach makes use of the fact, that the ratio of Ps atoms in the singlet and the triplet states is larger in a magnetic field applied parallel to the positron-spin polarization than in an antiparallel field.

  3. A Doppler-broadening facility for positron spin relaxation (e+SR) experiments

    International Nuclear Information System (INIS)

    A set-up is described for the determination of the spin polarization of positrons emitted from radioactive sources that makes use of the dependence of the Doppler broadening of the 511 keV annihilation photon line on the strength and direction (with regard to the spin polarization) of an applied magnetic field. In the so-called e+SR (positron spin relaxation) technique the sample to be investigated is part of the e+-spin polarimeter. Its application to the investigation of positronium formation in condensed matter is illustrated using crystalline quartz as an example. The method earlier applied to the positron annihilation in magnetized ferromagnets is now transferred to the detection of positronium (Ps) in condensed matter. This new approach makes use of the fact, that the ratio of Ps atoms in the singlet and the triplet states is larger in a magnetic field applied parallel to the positron-spin polarization than in an antiparallel field

  4. Auger Recombination in Self-Assembled Quantum Dots: Quenching and Broadening of the Charged Exciton Transition.

    Science.gov (United States)

    Kurzmann, Annika; Ludwig, Arne; Wieck, Andreas D; Lorke, Axel; Geller, Martin

    2016-05-11

    In quantum dots (QDs), the Auger recombination is a nonradiative process in which the electron-hole recombination energy is transferred to an additional carrier. It has been studied mostly in colloidal QDs, where the Auger recombination time is in the picosecond range and efficiently quenches the light emission. In self-assembled QDs, on the other hand, the influence of Auger recombination on the optical properties is in general neglected, assuming that it is masked by other processes such as spin and charge fluctuations. Here, we use time-resolved resonance fluorescence to analyze the Auger recombination and its influence on the optical properties of a single self-assembled QD. From excitation-power-dependent measurements, we find a long Auger recombination time of about 500 ns and a quenching of the trion transition by about 80%. Furthermore, we observe a broadening of the trion transition line width by up to a factor of 2. With a model based on rate equations, we are able to identify the interplay between tunneling and Auger rate as the underlying mechanism for the reduced intensity and the broadening of the line width. This demonstrates that self-assembled QDs can serve as an ideal model system to study how the charge recapture process, given by the band-structure surrounding the confined carriers, influences the Auger process. Our findings are not only relevant for improving the emission properties of colloidal QD-based emitters and dyes, which have recently entered the consumer market, but also of interest for more visionary applications, such as quantum information technologies, based on self-assembled quantum dots. PMID:27087053

  5. The influence of gas composition in dielectric barrier discharges on the broadening of the hydrogen Hα transition

    International Nuclear Information System (INIS)

    Line profiles of the Hα transition emitted from dielectric barrier discharges exhibit large broadening. This can be related to the Stark effect, taking place in plasmas and leading to broadening and shift of spectral lines due to interaction of the emitter with electric fields. These fields may originate from charged particles in the plasma as well as from external sources. The first mentioned source is dominating in the case of plasmas in thermal equilibrium or being close to such state. In inhomogeneous, non-equilibrium, and pulsed plasmas external electric field sources may dominate over the 'internal' micropoles of the plasma. In the case of dielectric barrier discharges the external electric fields are indeed the dominating agents for the formation of the Hα transition. Applying an experimental setup for polarization sensitive measurements, Hα line profiles have been measured from dielectric barrier discharges using two gas mixtures: H2+Ar and H2+He. The analysis of measured spectra, which takes into account the splitting of Stark components, allows determining the 'external' field strengths in the discharge volume. The differences between Hα line profiles obtained in both gas mixtures may be explained in terms of different interactions of hydrogen molecules and atoms with noble gas atoms. The determined field strengths acting on the emitter (hydrogen atom) may be applied for modeling of dielectric barrier discharges. (author)

  6. Strategies for broadening public involvement in space developments

    Science.gov (United States)

    Harris, Philip R.

    1992-01-01

    There is widespread public interest in and goodwill toward the space program. For NASA's plans for the next 25 years to be achieved, this public reservoir of support needs to be tapped and channeled. NASA endeavors have to reach out beyond the scientific, technological, and aerospace communities to foster wider participation in space exploration and exploitation. To broaden NASA support and spread out the financing of space activities, recommendations for consideration are offered in the area of economics, political, institutional, international, and managerial areas.

  7. Theoretical Manifestation of the Broadening Effect on Photoelectron Angular Distributions

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Tao(张敬涛); ZHOU Lan(周岚); ZHANG Wen-Qi(张文琦); XU Zhi-Zhan(徐至展); GUO Dong-Sheng(郭东升); R.R.Freeman

    2003-01-01

    The broadening effect in photoelectron angular distributions (PADs) observed by Freeman et al. Is studied theoretically. Using a nonperturbative scattering theory developed for multiphoton ionization with the inclusion of spontaneous emission, we calculate the PADs for above-threshold ionization (ATI) peaks. The numerical calculations from our theory reproduce the kinetic-energy dependence and the laser-intensity dependence of PADs of ATI peaks observed by Freeman et al., [Phys. Rev. Lett. 57 (1986) 3156] and provide an evidence for the existence of the ponderomotive momentum of intense laser fields.

  8. Pressure broadening of the ((dt. mu. )dee)* formation resonances

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J.S.; Leon, M.; Padial, N.T.

    1988-12-27

    The treatment of ((dt..mu..)dee)* formation at high densities as a pressure broadening process is discussed. Cross sections for collisions of the complex (dt..mu..)dee, and of the D/sub 2/ molecule from which it is formed, with the bath molecules have been accurately calculated. These cross sections are used to calculate the collisional width in three variations of the impact approximation that have been proposed for this problem. In general, the quasistatic approximation is shown to satisfy the usual conditions of muon-catalyzed fusion better than does the impact approximation. A preliminary rough treatment is presented to illustrate the quasistatic approximation.

  9. Linking the thermodynamic temperature to an optical frequency: recent advances in Doppler broadening thermometry

    Science.gov (United States)

    2016-01-01

    Laser spectroscopy in the linear regime of radiation–matter interaction is a powerful tool for measuring thermodynamic quantities in a gas at thermodynamic equilibrium. In particular, the Doppler effect can be considered a gift of nature, linking the thermal energy to an optical frequency, namely the line centre frequency of an atomic or molecular spectral line. This is the basis of a relatively new method of primary gas thermometry, known as Doppler broadening thermometry (DBT). This paper reports on the efforts that have been carried out, in the last decade, worldwide, to the end of making DBT competitive with more consolidated and accurate methodologies, such as acoustic gas thermometry and dielectric constant gas thermometry. The main requirements for low-uncertainty DBT, of both theoretical and technical nature, will be discussed, with a special focus on those related to the line shape model and to the frequency scale. A deep comparison among the different molecules that have been selected in successful DBT implementations is also reported. Finally, for the first time, to the best of my knowledge, the influence of refractive index effects is discussed. PMID:26903093

  10. Spectral-Kinetic Coupling and Effect of Microfield Rotation on Stark Broadening in Plasmas

    Directory of Open Access Journals (Sweden)

    Alexander V. Demura

    2014-07-01

    Full Text Available The study deals with two conceptual problems in the theory of Stark broadening by plasmas. One problem is the assumption of the density matrix diagonality in the calculation of spectral line profiles. This assumption is closely related to the definition of zero wave functions basis within which the density matrix is assumed to be diagonal, and obviously violated under the basis change. A consistent use of density matrix in the theoretical scheme inevitably leads to interdependence of atomic kinetics, describing the population of atomic states with the Stark profiles of spectral lines, i.e., to spectral-kinetic coupling. The other problem is connected with the study of the influence of microfield fluctuations on Stark profiles. Here the main results of the perturbative approach to ion dynamics, called the theory of thermal corrections (TTC, are presented, within which the main contribution to effects of ion dynamics is due to microfield fluctuations caused by rotations. In the present study the qualitative behavior of the Stark profiles in the line center within predictions of TTC is confirmed, using non-perturbative computer simulations.

  11. Linking the thermodynamic temperature to an optical frequency: recent advances in Doppler broadening thermometry.

    Science.gov (United States)

    Gianfrani, Livio

    2016-03-28

    Laser spectroscopy in the linear regime of radiation-matter interaction is a powerful tool for measuring thermodynamic quantities in a gas at thermodynamic equilibrium. In particular, the Doppler effect can be considered a gift of nature, linking the thermal energy to an optical frequency, namely the line centre frequency of an atomic or molecular spectral line. This is the basis of a relatively new method of primary gas thermometry, known as Doppler broadening thermometry (DBT). This paper reports on the efforts that have been carried out, in the last decade, worldwide, to the end of making DBT competitive with more consolidated and accurate methodologies, such as acoustic gas thermometry and dielectric constant gas thermometry. The main requirements for low-uncertainty DBT, of both theoretical and technical nature, will be discussed, with a special focus on those related to the line shape model and to the frequency scale. A deep comparison among the different molecules that have been selected in successful DBT implementations is also reported. Finally, for the first time, to the best of my knowledge, the influence of refractive index effects is discussed. PMID:26903093

  12. Determining europium compositional fluctuations in partially stabilized zirconia nanopowders: a non-line-broadening-based method.

    Science.gov (United States)

    Marin, Riccardo; Sponchia, Gabriele; Back, Michele; Riello, Pietro

    2016-02-01

    A method is reported for assessing the compositional fluctuations in a ceramic sample, based only on the determination of the crystalline lattice parameters. Pure tetragonal phase partially stabilized zirconia powders are synthesized through the co-precipitation method by incorporating 4% Eu(3+). The powder is subjected to compression cycles to promote the tetragonal-to-monoclinic transformation. The Rietveld analysis of the X-ray powder diffraction patterns, recorded after each compression cycle, gives information about the lattice parameters and monoclinic phase content. The determination of europium content in the residual tetragonal phase is accomplished considering the unit cell volume of t-ZrO2 using Vegard's law. Using this information the compositional fluctuations over the sample were determined by considering two possible distributions of lanthanide ion content in the powders: a Gaussian and a Log-normal one. It was found that the Gaussian distribution better fits the experimental data. It was eventually demonstrated that these results are physically meaningful. PMID:26830794

  13. Improving Program Design and Assessment with Broadening Participation Resources

    Science.gov (United States)

    Siegfried, D.; Johnson, A.; Thomas, S. H.; Fauver, A.; Detrick, L.

    2012-12-01

    Many theoretical and research-based approaches suggest how to best use mentoring to enhance an undergraduate research program. The Institute for Broadening Participation's Pathways to Engineering and Pathways to Ocean Sciences projects synthesized a set of mentoring studies, theoretical sources, and other texts pertinent to undergraduate research program design into a suite of practical tools that includes an online mentoring manual, an online reference library of mentoring and diversity literature, and practical guides such as Using Social Media to Build Diversity in Your REU. The overall goal is to provide easy-to-access resources that can assist faculty and program directors in implementing or honing the mentoring elements in their research programs for undergraduates. IBP's Online Mentoring Manual addresses common themes, such as modeling, student self-efficacy, career development, retention and evaluation. The Online Diversity Reference Library provides a comprehensive, annotated selection of key policy documents, research studies, intervention studies, and other texts on broadening participation in science, technology, engineering and mathematics. IBP's suite of tools provides the theoretical underpinnings and research findings that can help leaders in education integrate site-appropriate mentoring elements into their educational programs. Program directors and faculty from a variety of program types and disciplines have benefitted from using the Manual and other resources. IBP continues the work of translating and synthesizing theory to practice and welcomes your participation and partnership in that effort.

  14. Multiple scattering and $p_t$-broadening at RHIC energies

    CERN Document Server

    Papp, G; Fái, G; Lévai, Peter; Zhang, Y

    2002-01-01

    In ultrarelativistic heavy-ion collisions, in the 2 GeV$broadening of the expected hadronic (e.g. pion) $p_\\perp$ spectra relative to proton-proton ($pp$) collisions. Thus, higher transverse-momentum regions are populated than in $pp$ collisions. In a perturbative QCD based calculation we include the intrinsic transverse momentum ($k_\\perp$) of the partons in the nucleon (determined from $pp$ collisions), augmented by the extra broadening obtained via a systematic analysis of proton-nucleus ($pA$) collisions in the energy range 17$<\\sqrt{s}<$ 39 AGeV. The original polynomial spectra are modified, and a nearly exponential spectrum appears in the region 2$\\lesssim p_\\perp\\lesssim 3.5$ GeV. At present RHIC energies ($\\sqrt{s}=$130 AGeV), the slope of the calculated spectra is reminiscent of that of fluid-dynamical descriptions, but lacks any thermal ori...

  15. Uranium dioxide crystalline binding effect on Doppler broadening

    International Nuclear Information System (INIS)

    When the crystalline bindings are weak, the Doppler broadening of resonances can be obtained with the same formula as for the free gas. But the physical temperature must be replaced by an effective temperature which is higher. The effective temperature depends on the physical temperature and on a parameter theta which is called the Debye temperature. For uranium dioxide, the value of theta seems top be high and not well known. This fact can infer important consequences in reactor physics. For a light water reactor, the reactivity effect of a theta value increasing from 0 K to 620 K can reach -215.10-5 at room temperature and affect the temperature coefficient of the reactor for 15%. For knowing the Debye temperature with a good accuracy we deduced a theta value from Doppler experiments which were performed in a critical facility. We obtained a value of 615 K which is in good agreement with theoretical computations using several crystal vibration models. This high value imposes to take into account the crystalline bindings in Doppler broadening calculations

  16. N2 and O2 pressure broadening and pressure shift in the 4ν2 band of 16O12C32S

    Science.gov (United States)

    Galalou, S.; Ben Mabrouk, K.; Aroui, H.; Kwabia Tchana, F.; Willaert, F.; Flaud, J.-M.

    2011-12-01

    To measure accurately OCS concentrations in planetary atmospheres, it is important to know precisely nitrogen and oxygen pressure broadening and pressure-induced shift coefficients for the lines used in the retrievals. We present in this study the corresponding coefficients for lines of the P and R branches of the 4ν2 band of the primary isotopologue of carbonyl sulfide (16O12C32S).For this purpose, infrared absorption spectra of a natural carbonyl sulfide (OCS) gas sample were recorded at an unapodized resolution of 0.004 cm-1, at room temperature for different pressures of N2 and O2, using a Bruker IFS125HR spectrometer at the LISA Laboratory in France. The line parameters were derived using the multispectrum fitting method applied to the measured shapes of the lines, including the interference effects caused by the line overlaps.The results are compared with earlier measurements and with values calculated using a semi-classical model based upon the Robert and Bonamy formalism that reproduces rather well the experimental m (m=-J for P(J) lines and m=J+1 for R(J) lines) quantum number dependence of the N2 and O2 broadening coefficients. On the other hand most of the lines studied here have positive shift coefficients, which do not show any systematic dependence on m. However, in previous studies of the ν3, 2ν3 and ν2 bands, these coefficients were negative for all lines.

  17. Multispectrum analysis of the ν4 band of CH3CN: Positions, intensities, self- and N2-broadening, and pressure-induced shifts

    International Nuclear Information System (INIS)

    A multispectrum nonlinear least-squares fitting technique was applied to measure accurate zero-pressure line center positions, Lorentz self- and nitrogen (N2)-broadened half-width coefficients, and self- and N2-pressure-induced shift coefficients for over 700 transitions in the parallel ν4 band of CH3CN near 920 cm-1. Fifteen high-resolution (0.0016 cm-1) laboratory absorption spectra of pure and N2-broadened CH3CN recorded at room temperature using the Bruker IFS 125HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington, USA, were analyzed simultaneously assuming standard Voigt line shapes. Short spectral intervals containing manifolds of transitions from the same value of J were fitted together. In all, high-precision line parameters were obtained for P(44)-P(3) and R(0)-R(46) manifolds. As part of the analysis, quantum assignments were extended, and the total internal partition function sum was calculated for four isotopologs: 12CH312CN, 13CH312CN, 12CH313CN, and 13CH313CN. Measurements of N2 broadening, self-broadening, N2-shift, and self-shift coefficients for transitions with J up to 48 and K up to 12 were measured for the first time in the mid-infrared. Self-broadened half-width coefficients were found to be very large (up to ∼2 cm-1 atm-1 at 296 K). Ratios of self-broadened half-width coefficients to N2-broadened half-width coefficients show a compact distribution with rotational quantum number in both the P and R branches that range from ∼4.5 to 14 with maxima near vertical bar m vertical bar =24, where m=-J'', J'', and J''+1 for P, Q, and R lines, respectively. Pressure-induced shifts for N2 are small (few exceed ±0.006 cm-1 atm-1 at 294 K) and are both positive and negative. In contrast, self-shift coefficients are large (maxima of about ±0.08 cm-1 atm-1 at 294 K) and are both positive and negative as a function of rotational quantum numbers. The present measured half-widths and

  18. Optical properties of an inhomogeneously broadened multilevel V-system in the weak and strong probe regimes

    CERN Document Server

    Kaur, Paramjit; Wasan, Ajay

    2015-01-01

    We present a theoretical model, using density matrix approach, to study the effect of weak as well as strong probe field on the optical properties of an inhomogeneously broadened multilevel V-system of the $^{87}$Rb D2 line. We consider the case of stationary as well as moving atoms and perform thermal averaging at room temperature. The presence of multiple excited states results in asymmetric absorption and dispersion profiles. In the weak probe regime, we observe the partial transparency window due to the constructive interference occurs between transition pathways at the line center. In a room temperature vapour, we obtain an increased linewidth of the transparency window and steep positive dispersion. For a strong probe regime, the transparency window with normal dispersion switches to enhanced absorption with anomalous dispersion at the line center. Here, we show how the electromagnetically induced transparency (EIT) depends on the polarizations of the applied fields. We also discuss the transient behavi...

  19. Tunable diode laser measurement of self broadening versus temperature of five close ammonia transitions of the v2 band

    International Nuclear Information System (INIS)

    Self broadening coefficients have been measured as a functional of temperature form 192 to 377 K for five transition lines of the band of ammonia. The results have been compared with theoretical calculations performed in the semiclassical impact approximation, and although one hot transition does not fit well in this scheme, there is in general a fairly good agreement. Moreover there is also an experimental and theoretical evidence against the commonly assumed power law for the temperature dependence. More measurements are needed to clarify the position of the hot transitions in this respect and to verify the extent of validity of the power law in general

  20. A neutron resonance spin echo (NRSE) spectrometer for high resolution measurement of phonon linewidths. Observation of Pitaevskii broadening in superfluid Helium

    International Nuclear Information System (INIS)

    Complete text of publication follows. We report on the performance and results of the Resonance Spin Echo Spectrometer (NRSE), which was developed at the TU Muenchen and installed at the triple axis spectrometer FLEX at BENSC Berlin. This NRSE instrument allows to measure phonon line widths with sub-μeV resolution by focusing the spin-echo resolution function to the slope of the dispersion curve. Recent NRSE measurements on superfluid Helium show a broadening of the roton linewidths in the wavevector region 2.2 A-1 -1. This broadening (Pitaevskii broadening) is expected to result from the emission of low energy phonons, which is kinematically allowed only in those regions of the dispersion curve, where the group velocity vg is higher than the velocity of sound c. In the roton region the available dispersion data are not accurate enough to decide if vg > c. A precise measurement was performed of the excitation energies using the NRSE technique. The results show vg -1 -1, which implies that the roton should be stable with respect to the simple decay mechanism assumed above. An explanation for the observed line broadening is still missing. (author)

  1. Phonon Properties of Materials from Neutron Resonance Doppler Broadening Measurements

    Science.gov (United States)

    Eric Lynn, J.

    2002-12-01

    At low temperatures the Doppler broadened widths of neutron resonances are strongly affected by the phonon characteristics of the material used for making the cross-section measurement. The Doppler width can be expressed in terms of the moments of the phonon spectrum carried by the atomic species with the resonant cross-section. Cross-section measurements made with tungsten and tantalum metals are reviewed here and compared with phonon information obtained by other methods. Applications of the method to a plutonium-gallium alloy and to some lanthanum barium cuprates are described briefly. We discuss possible extensions of the technique and how an epithermal flight path at the SNS may be advantageous.

  2. Coincidence Doppler Broadening of Positron Annihilation Radiation in Fe

    Science.gov (United States)

    do Nascimento, E.; Vanin, V. R.; Maidana, N. L.; Helene, O.

    2013-06-01

    We measured the Doppler broadening annihilation radiation spectrum in Fe, using 22NaCl as a positron source, and two Ge detectors in coincidence arrangement. The two-dimensional coincidence energy spectrum was fitted using a model function that included positron annihilation with the conduction band and 3d electrons, 3s and 3p electrons, and in-flight positron annihilation. Detectors response functions included backscattering and a combination of Compton and pulse pileup, ballistic deficit and shaping effects. The core electrons annihilation intensity was measured as 16.4(3) %, with almost all the remainder assigned to the less bound electrons. The obtained results are in agreement with published theoretical values.

  3. Novel data evaluation algorithm for Coincident Doppler Broadening Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pikart, Philip, E-mail: philip@pikart.de [Technische Universität München, Physics Department E21, Lichtenbergstr. 1, 85747 Garching (Germany); Hugenschmidt, Christoph [Forschungsneutronenquelle Heinz Maier-Leibnitz (FRM II), Lichtenbergstr. 1, 85747 Garching (Germany)

    2014-06-01

    In Coincident Doppler Broadening Spectroscopy (CDBS) the sum energy of the annihilation photons is checked to be 1022 keV, to validate the measurement of an undisturbed two-gamma electron–positron decay event. The events are stored in a two-dimensional acquisition matrix. A new algorithm is presented, which optimizes the extraction of the one-dimensional CDBS spectrum from this matrix by enhanced background suppression by the use of variable size bins. - Highlights: • A more efficient data evaluation algorithm for CDBS is presented. • The SNR in parts of the CDB spectrum is improved by one order of magnitude. • Variable binning combines good resolution with lowest measurement error. • The mean detector resolution is extracted from the CDBS data.

  4. Brillouin resonance broadening due to structural variations in nanoscale waveguides

    CERN Document Server

    Wolff, Christian; Steel, Michael J; Eggleton, Benjamin J; Poulton, Christopher G

    2015-01-01

    We study the impact of structural variations (that is slowly varying geometry aberrations and internal strain fields) on the resonance width and shape of stimulated Brillouin scattering (SBS) in nanoscale waveguides. We find that they lead to an inhomogeneous resonance broadening through two distinct mechanisms: firstly, the acoustic frequency is directly influenced via mechanical nonlinearities; secondly, the optical wave numbers are influenced via the opto-mechanical nonlinearity leading to an additional acoustic frequency shift via the phase-matching condition. We find that this second mechanism is proportional to the opto-mechanical coupling and, hence, related to the SBS-gain itself. It is absent in intra-mode forward SBS, while it plays a significant role in backward scattering. In backward SBS increasing the opto-acoustic overlap beyond a threshold defined by the fabrication tolerances will therefore no longer yield the expected quadratic increase in overall Stokes amplification. Our results can be tra...

  5. GOSAT-2014 methane spectral line list

    International Nuclear Information System (INIS)

    The updated methane spectral line list GOSAT-2014 for the 5550–6240 cm−1 region with the intensity cutoff of 5×10–25 cm/molecule at 296 K is presented. The line list is based on the extensive measurements of the methane spectral line parameters performed at different temperatures and pressures of methane without and with buffer gases N2, O2 and air. It contains the following spectral line parameters of about 12150 transitions: line position, line intensity, energy of lower state, air-induced and self-pressure-induced broadening and shift coefficients and temperature exponent of air-broadening coefficient. The accuracy of the line positions and intensities are considerably improved in comparison with the previous version GOSAT-2009. The improvement of the line list is done mainly due to the involving to the line position and intensity retrieval of six new spectra recorded with short path way (8.75 cm). The air-broadening and air-shift coefficients for the J-manifolds of the 2ν3(F2) band are refitted using the new more precise values of the line positions and intensities. The line assignment is considerably extended. The lower state J-value was assigned to 6397 lines representing 94.4% of integrated intensity of the considering wavenumber region. The complete assignment was done for 2750 lines. - Highlights: • The upgrade of the GOSAT methane line list in the 5550–6240 cm−1 region is done. • 12,146 experimental methane line positions and intensities are retrieved. • 6376 lower energy levels for methane lines are determined

  6. Broadening soybean genetic basis in the northeast of China

    Institute of Scientific and Technical Information of China (English)

    WangJinling

    1994-01-01

    The bottle neek of advancement of soybean breeding inthe Northeast of China is the lack of genetic diversity of the parents used in cross breeding.In order to overcome this constrained condition,under the sponsorship of China National Committe of Natural Science Fundation,a network project with the topic"Broadening and Improving of the Genetic Basis of the Northeast Soybeans" was established in 1990,and the Northeast agricultural University was apointed to take charge of the project.The project included the following four items:I.Breeding high yield and improved quality Northeast Soybeans,directed by Hcilongjiang Academy of Agricultural Sciencee .II.Development of new soybean gerplasms highly resistant to diseases epidemic in Northeast China directed by Northeast Agricultural University.Ⅲ.Exploitation of the potential of wild and semicultivated soybeans for broadening and improving the genetic basis of Northeast soybeans,directed by Jilin Academy of Agricultural Science.Ⅳ.Improving methods and technique for development of new soybean genetic resources.directed by Nanjing Agricultural University .Each item contained several research subjects conducted by research workers of different institutes of agricultural sicences.During the period 1991-1992.considerable promising new germplasms had been discovered or developed.The new germplasms not only possessed specific improved characters but also behaved with appropriate ecological types adapted to different conditions of Northeast.Among the numerous new germplasms developed.Gong Jio 8757-3 had a protein content of 49.41%,100 seed weight 16-17g,and acceptable agronomic characters,which was considered a very valuable new high protein content germplasm.Such developed new germplasma with enforced and imprved genetic basis will be used primarily as parents in soybean cross breeding.

  7. Broadening of nuclear engineering programs: An engineering physics approach at Rensselaer

    International Nuclear Information System (INIS)

    With the maturing of nuclear engineering as an academic discipline and the uncertainty surrounding the nuclear industry, attention is being increasingly turned to ways in which the base of traditional nuclear engineering programs in universities can be broadened to make them more attractively useful to a wider class of potential students and employers while maintaining the strengths in mainstream areas of nuclear technology. An approach that seems to provide a natural evolution combining the existing programmatic strengths, infrastructure, and resources with the trending needs of a broad segment of diversified industries is the development and initiation of an engineering physics degree program as an adjunct to an established nuclear engineering curriculum. In line with these developments, a new comprehensive academic program offering baccalaureate, master's, and doctoral degrees in engineering physics has been developed and formally instituted at Rensselaer Polytechnic Institute (RPI). It provides a valuable opportunity for students to pursue education and research that cuts across traditional disciplinary lines, leading to a wide variety of career opportunities in industry, government, national research and defense laboratories, and academia

  8. The rotational broadening and the mass of the donor star of GRS 1915+105

    CERN Document Server

    Harlaftis, E T

    2004-01-01

    The binary parameters of the microquasar GRS 1915+105 have been determined by the detection of Doppler-shifted 12CO and 13CO lines in its K-band spectrum (Greiner et al., 2001, Nature, 414, 522). Here, we present further analysis of the same K-band VLT spectra and we derive a rotational broadening of the donor star of V sin i=26+-3 km/s from the 12CO/13CO lines. Assuming that the K-type star is tidally locked to the black hole and is filling its Roche-lobe surface, then the implied mass ratio is q = M_d/M_x = 0.058+-0.033. This result, combined with (P, K, i)=(33.5 d, 140 km/s, 66 deg) gives a more refined mass estimate for the black hole, $M_x=14.0+-4.4 M_{\\odot}$, than previously estimated, using an inclination of i=66+-2 deg (Fender et al. 1999) as derived from the orientation of the radio jets and a more accurate distance. The mass for the early K-type giant star is $M_d=0.81\\pm0.53 M_{\\odot}$, consistent with a more evolved stripped-giant donor star in GRS 1915+105 than, for example, the donor star of th...

  9. Measurement Of Magnetic Fields In Magnetized Plasmas Using Zeeman Broadening Diagnostics

    Science.gov (United States)

    Haque, Showera; Wallace, Matthew S.; Neill, Paul; Presura, Radu

    2015-11-01

    The Zeeman effect has been used to measure the magnetic field in high energy density plasmas. The measurements are difficult in this regime because the line broadening due to the high plasma density and temperature surpasses the Zeeman splitting. Using an idea proposed by Tessarin et al. (2011), we have measured the field in magnetized laser plasmas and the magnetized precursor of wire array z-pinches. Time-gated spectra with one-dimensional space-resolution were obtained at the Nevada Terawatt Facility for laser plasmas created by 20 J, 1 ns Leopard laser pulses, and expanding in the azimuthal magnetic field produced by the 0.6 MA Zebra pulsed power generator, and for wire array plasmas driven by the 1 MA configuration of the Zebra generator. We explore the response of the Al III 4s 2S1/2- 4p 2P1 / 2 , 3 / 2 doublet components and the C IV 3s 2S1/2- 3p 2P1 / 2 , 3 / 2 doublet components to the external magnetic field spatially along the plasma. In these measurements the Zeeman splitting was not resolved, but the magnetic field strength was measured from the difference between the widths of the line profiles. This work was supported by the DOE/OFES grant DE-SC0008829 and DOE/NNSA contract DE-FC52-06NA27616.

  10. Temperature Dependences of Air-Broadening and Shift Parameters in the ν_3 Band of Ozone

    Science.gov (United States)

    Smith, Mary Ann H.; Devi, V. Malathy; Benner, D. Chris

    2015-06-01

    Line parameter errors can contribute significantly to the total errors in retrievals of terrestrial atmospheric ozone concentration profiles using the strong 9.6-μm band, particularly for nadir-viewing experiments Detailed knowledge of the interfering ozone signal is also needed for retrievals of other atmospheric species in this spectral region. We have determined Lorentz air-broadening and pressure-induced shift coefficients along with their temperature dependences for a number of transitions in the ν_3 fundamental band of 16O_3. These results were obtained by applying the multispectrum nonlinear least-squares fitting technique to a set of 31 high-resolution infrared absorption spectra of O_3 recorded at temperatures between 160 and 300 K with several different room-temperature and coolable sample cells at the McMath-Pierce Fourier transform spectrometer at the National Solar Observatory on Kitt Peak. We compare our results with other available measurements and with the ozone line parameters in the HITRAN database. J.~Worden et al., J.~Geophys.~Res. 109 (2004) 9308-9319. R.~Beer et al., Geophys.~Res.~Lett. 35 (2008) L09801. D.~Chris Benner et al., JQSRT 53 (1995) 705-721. Rothman et al., J. Quant. Spectrosc. Radiat. Transfer 130 (2013) 4. JQSRT 130 (2013) 4-50.

  11. Line shape modeling in warm and dense hydrogen plasmas

    Science.gov (United States)

    Ferri, S.; Calisti, A.; Mossé, C.; Talin, B.; Gigosos, M. A.; González, M. A.

    2007-05-01

    A study of hydrogen lines emitted in warm ( T˜1eV) and dense ( N≥1018cm -3) plasmas is presented. Under such plasma conditions, the electronic and the ionic contributions to the line width are comparable, and the general question related to a transition from impact to quasi-static broadening arises not only for the far wings but also for the core of spectral lines. The transition from impact to quasi-static broadening for electrons is analyzed by means of Frequency Fluctuation Model (FFM). In parallel, direct integration of the semi-classical evolution equation is performed using electron electric fields calculated by Molecular Dynamics (MD) simulations that permit one to correctly describe the emitter environment. New cross comparisons between benchmark MD simulations and FFM are carried out for electron broadening of the Balmer series lines, and, especially, for the Hα line, for which a few experiments in the warm and dense plasma regimes are available.

  12. Measurements of pressure induced self-broadening and frequency shift coefficients of methane R9 manifold of 2v3 band

    Institute of Scientific and Technical Information of China (English)

    Weiguang Ma; Lei Dong; Wangbao Yin; Linfeng Li; Lei Zhang; Suotang Jia

    2005-01-01

    @@ An external-cavity diode laser (ECDL) has been used to investigate pressure-induced self-broadening as well as frequency shift of 2v3 band R9 manifold of methane. A phase sensitivity detection technology has been employed to determine the pressure induced frequency shift coefficient, however, which is obtained by line shape analyses of the recorded absorption spectrum. F1 and F2 unresolved double lines near 6105.626 cm-1 were measured as an object because they are often used to the high sensitivity detection of trace methane. The results show that the self-broadening and pressure induced frequency shift coefficients are 0.0232±0.003 and 0.0055±0.0007 MHz/Pa, respectively.

  13. Gamma-ray line transients

    International Nuclear Information System (INIS)

    Early interpretations of the variability of the narrow 0.511 MeV annihilation line from the Galactic center (GC) were confused by the unrecognized presence of a very extended component (mid 70s-mid 80s). Transient behavior was suggested by comparisons of measurements made by instruments with comparable fields of view, and by detection of other lines which could be interpreted as broadened and Doppler-shifted versions of the line. A new generation of instruments (late 80s-early 90s) provided more compelling evidence, by improved imaging capability (identifying a known transient high-energy candidate source, 1E 1740.7-2942), and by improved sensitivity. Additional broadened, shifted, and Compton-scattered derivatives of the annihilation line were detected from this and other sources. At the same time, theoretical developments suggested exciting new physics which might arise in the accretion regimes around black holes, of which these features would be important diagnostics. In the GRO era the existence of such transient lines has been brought into question by the failure of long-term monitoring to detect them. A seemingly critical observation of the GC by three different instruments simultaneously, in which transient emission was detected only by one, provides the strongest evidence that the earlier results were in error. Recent developments in accretion disk theory have weakened the theoretical case for the lines. I draw conclusions concerning the nature of scientific inquiry and public outreach efforts in science

  14. Broadening the Participation of Native Americans in Earth Science

    Science.gov (United States)

    Bueno Watts, Nievita

    Climate change is not a thing of the future. Indigenous people are being affected by climate changes now. Native American Earth scientists could help Native communities deal with both climate change and environmental pollution issues, but are noticeably lacking in Earth Science degree programs. The Earth Sciences produce the lowest percentage of minority scientists when compared with other science and engineering fields. Twenty semi-structured interviews were gathered from American Indian/ Alaska Native Earth Scientists and program directors who work directly with Native students to broaden participation in the field. Data was analyzed using qualitative methods and constant comparison analysis. Barriers Native students faced in this field are discussed, as well as supports which go the furthest in assisting achievement of higher education goals. Program directors give insight into building pathways and programs to encourage Native student participation and success in Earth Science degree programs. Factors which impede obtaining a college degree include financial barriers, pressures from familial obligations, and health issues. Factors which impede the decision to study Earth Science include unfamiliarity with geoscience as a field of study and career choice, the uninviting nature of Earth Science as a profession, and curriculum that is irrelevant to the practical needs of Native communities or courses which are inaccessible geographically. Factors which impede progress that are embedded in Earth Science programs include educational preparation, academic information and counseling and the prevalence of a Western scientific perspective to the exclusion of all other perspectives. Intradepartmental relationships also pose barriers to the success of some students, particularly those who are non-traditional students (53%) or women (80%). Factors which support degree completion include financial assistance, mentors and mentoring, and research experiences. Earth scientists

  15. The Role of Doppler Broadening in Electromagnetically Induced Transparency and Autler-Townes Splitting in Open Molecular Systems

    CERN Document Server

    Lazoudis, A; Hansson, A; Kirova, T; Li, L; Lyyra, A M; Magnes, J; Qi, P; Spano, F C

    2005-01-01

    We describe in this Letter how inhomogeneous line broadening affects the Autler-Townes (AT) splitting in a three level open molecular cascade system. For moderate Rabi frequencies in the range of 300 to 500 MHz the fluorescence line shape from the uppermost level |3> in this system depends strongly on the frequency ratio of the two laser fields. However, the fluorescence spectrum of the intermediate level |2> appears as expected. We provide a description of the conditions for optimally resolved AT splitting in terms of the probe laser/coupling field frequency ratio and laser propagation geometry based on our theoretical analysis of the Doppler integral. This is important for applications such as molecular angular momentum alignment as well as for the measurement of the transition dipole moment matrix element.

  16. Hyperfine structure effects in Doppler-broadening thermometry on water vapor at 1.4 μm

    Science.gov (United States)

    Domenica De Vizia, Maria; Odintsova, Tatyana; Gianfrani, Livio

    2016-04-01

    This article builds upon a previous work dealing with the budget of uncertainties associated to our recent determination of the Boltzmann constant by means of Doppler broadening thermometry. We report on the outcomes of theoretical calculations and numerical simulations aimed to precisely quantify the influence of the unresolved hyperfine structure of a given ortho component of the \\text{H}218 O spectrum at 1.4 μm on the measurement of the Doppler width of the line itself. We have found that, if the hyperfine structure of the {{4}4,1}\\to {{4}4,0} line of the {ν1}+{ν3} band was ignored, the spectroscopic measurement of the Boltzmann constant would be affected by a relative systematical deviation of 4\\cdot {{10}-8} .

  17. Momentum broadening in unstable quark-gluon plasma

    CERN Document Server

    Carrington, M E; Schenke, B

    2016-01-01

    Quark-gluon plasma produced at the early stage of ultrarelativistic heavy ion collisions is unstable, if weakly coupled, due to the anisotropy of its momentum distribution. Chromomagnetic fields are spontaneously generated and can reach magnitudes much exceeding typical values of the fields in equilibrated plasma. We consider a high energy test parton traversing an unstable plasma that is populated with strong fields. We study the momentum broadening parameter $\\hat q$ which determines the radiative energy loss of the test parton. We develop a formalism which gives $\\hat q$ as the solution of an initial value problem, and we focus on extremely oblate plasmas which are physically relevant for relativistic heavy ion collisions. The parameter $\\hat q$ is found to be strongly dependent on time. For short times it is of the order of the equilibrium value, but at later times $\\hat q$ grows exponentially due to the interaction of the test parton with unstable modes and becomes much bigger than the value in equilibri...

  18. Workshops Without Walls: broadening access to science around the world.

    Science.gov (United States)

    Arslan, Betül K; Boyd, Eric S; Dolci, Wendy W; Dodson, K Estelle; Boldt, Marco S; Pilcher, Carl B

    2011-08-01

    The National Aeronautics and Space Administration (NASA) Astrobiology Institute (NAI) conducted two "Workshops Without Walls" during 2010 that enabled global scientific exchange--with no travel required. The second of these was on the topic "Molecular Paleontology and Resurrection: Rewinding the Tape of Life." Scientists from diverse disciplines and locations around the world were joined through an integrated suite of collaborative technologies to exchange information on the latest developments in this area of origin of life research. Through social media outlets and popular science blogs, participation in the workshop was broadened to include educators, science writers, and members of the general public. In total, over 560 people from 31 US states and 30 other nations were registered. Among the scientific disciplines represented were geochemistry, biochemistry, molecular biology and evolution, and microbial ecology. We present this workshop as a case study in how interdisciplinary collaborative research may be fostered, with substantial public engagement, without sustaining the deleterious environmental and economic impacts of travel. PMID:21829326

  19. Broadening Participation: Mentoring Community College Students in a Geoscience REU

    Science.gov (United States)

    Smith, M.; Osborn, J.

    2015-12-01

    Increasingly, REUs are recruiting from community colleges as a means of broadening participation of underrepresented minorities, women, and low-income students in STEM. As inclusion of community college students becomes normalized, defining the role of science faculty and preparing them to serve as mentors to community college students is a key component of well-designed programs. This session will present empirical research regarding faculty mentoring in the first two years of an NSF-REU grant to support community college students in a university's earth and environmental science labs. Given the documented benefits of undergraduate research on students' integration into the scientific community and their career trajectory in STEM, the focus of the investigation has been on the processes and impact of mentoring community college STEM researchers at a university serving a more traditionally privileged population; the degree to which the mentoring relationships have addressed community college students needs including their emotional, cultural and resource needs; and gaps in mentor training and the mentoring relationship identified by mentors and students.

  20. Workshops Without Walls: broadening access to science around the world.

    Directory of Open Access Journals (Sweden)

    Betül K Arslan

    2011-08-01

    Full Text Available The National Aeronautics and Space Administration (NASA Astrobiology Institute (NAI conducted two "Workshops Without Walls" during 2010 that enabled global scientific exchange--with no travel required. The second of these was on the topic "Molecular Paleontology and Resurrection: Rewinding the Tape of Life." Scientists from diverse disciplines and locations around the world were joined through an integrated suite of collaborative technologies to exchange information on the latest developments in this area of origin of life research. Through social media outlets and popular science blogs, participation in the workshop was broadened to include educators, science writers, and members of the general public. In total, over 560 people from 31 US states and 30 other nations were registered. Among the scientific disciplines represented were geochemistry, biochemistry, molecular biology and evolution, and microbial ecology. We present this workshop as a case study in how interdisciplinary collaborative research may be fostered, with substantial public engagement, without sustaining the deleterious environmental and economic impacts of travel.

  1. Peak broadening in paper chromatography and related techniques : V. Conditions for minimum separation time

    NARCIS (Netherlands)

    Lygny, C.L. de; Kok, E.C.M.

    1968-01-01

    In paper and thin-layer chromatography peak broadening is a function of the mean flow rate of the eluent, which in turn is a function of the distances of the starting point and solvent front from the eluent in the tank. Starting from the relationship between peak broadening and the positions of sta

  2. Characteristics of S-wave Envelope Broadening in the Changbaishan Tianchi Volcano

    Institute of Scientific and Technical Information of China (English)

    Fan Xiaoping; Li Qinghe; He Haibing; Yang Congjie; Jin Shumei

    2010-01-01

    High-frequency S-wave seismogram envelopes of microearthquakes broaden with increasing travel distance,a phenomenon known as S-wave envelope broadening.Multiple forward scattering and diffraction for the random inhomogeneities along the seismic ray path are the main causes of S-wave envelope broadening,so the phenomenon of S-wave envelope broadening is used to study the inhomogeneity of the medium.The peak delay time of an S-wave,which is defined as the time lag from the direct S-wave onset to the maximum amplitude arrival of its envelope.is accepted to quantify S-wave envelope broadening.204 small earthquake records in Changbaishan Tianchi volcano were analyzed by the S-wave envelope broadening algorithm.The results show that S-wave envelope broadening in the Changbaishan Tianchi volcano is obvious,and that the peak delay time of S-wave has a positive correlation with the hypocenter distance and frequency of the Swave.The relationships between the S-wave peak delay time and the hypocenter distance for different frequency bands were obtained using the statistics method.The results are beneficial to the understanding of the S-wave envelope broadening phenomena and the quantitative research on the inhomogeneities of the crust medium in the Changbaishan Tianchi volcano region.

  3. Power broadening effects on Electromagnetically Induced Transparency in $^{20}$Ne vapor

    CERN Document Server

    Lubotzky, Boaz; Kong, Tao; Katz, Nadav; Ron, Guy

    2014-01-01

    We report here the first observation of electromagnetically induced transparency (EIT) in $^{20}$Ne. The power broadening of the EIT linewidth is measured as a function of neon pressure and RF excitation power. Doppler effects on the EIT broadening are found even at low pressures and low intensities, where the linewidth should be governed only by homogeneous effects.

  4. An intercomparison of measured pressure-broadening, pressure shifting parameters of carbon dioxide and their temperature dependence

    International Nuclear Information System (INIS)

    An intercomparison of measured pressure-broadening and pressure-shifting coefficients for carbon dioxide absorption lines was done. The work focuses on collision systems where a significant number of data can be found (CO2–N2, CO2–O2, CO2–air, and CO2–CO2) and yield information important to applications related to Earth's atmosphere. The literature was searched for measured line shape parameter data for the collision systems mentioned above. Databases were created for each perturbing gas with the ro-vibrational transition as the key. Using these databases intercomparisons of the measurements of half-widths, their temperature dependence, and line shifts were made. The data allow the investigations of trends in the data with respect to the vibrational and the rotational quantum numbers, various line shape models, and isotopologue effects. The data were averaged and an estimated uncertainty determined. The averaged data sets are evaluated with respect to the need of the spectroscopic and remote sensing communities. In general many data points do not agree within the stated uncertainty estimate independent of the broadening species. Agreement between measurements of the temperature dependence of the half-width is in a poor state and the understanding of the temperature dependence of the line shift is in its infancy. The intercomparison data show more measurements are needed for the CO2–O2, CO2–N2 and CO2–CO2 systems. In addition to the half-width at 296 K, data are needed for the temperature dependence of the half-width and line shift. -- Highlights: • Literature search for half-width and line shift measurements for CO2 transitions. • N2–, O2–, air–, and CO2–CO2 collision systems studied. • Creation of databases of measured © and ™ for each collision system. • An intercomparison of the measured data. • Rot, vib, temp, isotopologue, and line shape model dependence of © and ™

  5. Analysis of pulse broadening induced by the second-order PMD

    Institute of Scientific and Technical Information of China (English)

    Fu Song-Nian; Wu Chong-Qing; Shum Ping

    2005-01-01

    We propose a new conception of depolarization vector to describe the effect of depolarization induced by the second-order polarization mode dispersion (PMD). Deriving the formula of pulse broadening induced by the secondorder PMD, we find that the polarization-dependent chromatic dispersion (PCD) always enhances the pulse broadening.However the depolarization vector decreases the pulse broadening. The pulse broadening is correlated with the bit-rate of a transmission system. By adjusting the directions of the Stokes vector of initial state of polarization, initial firstorder polarization dispersion vector and depolarization vector to be parallel to each other, one can obtain an optimum dispersion compensation.But when the PCD is not equal to zero, the optimum dispersion cannot achieve a complete compensation, and the minimum pulse broadening is equal to σ = ( 2/4) (DCF/T0).

  6. Theory of Self-Phase Modulation and Spectral Broadening

    Science.gov (United States)

    Shen, Y. R.; Yang, Guo-Zhen

    Self-phase modulation refers to the phenomenon in which a laser beam propagating in a medium interacts with the medium and imposes a phase modulation on itself. It is one of those very fascinating effects discovered in the early days of nonlinear optics (Bloembergen and Lallemand, 1966; Brewer, 1967; Cheung et al., 1968; Lallemand, 1966; Jones and Stoicheff, 1964; Shimizu, 1967; Stoicheff, 1963). The physical origin of the phenomenon lies in the fact that the strong field of a laser beam is capable of inducing an appreciable intensity-dependent refractive index change in the medium. The medium then reacts back and inflicts a phase change on the incoming wave, resulting in self-phase modulation (SPM). Since a laser beam has a finite cross section, and hence a transverse intensity profile, SPM on the beam should have a transverse spatial dependence, equivalent to a distortion of the wave front. Consequently, the beam will appear to have self-diffracted. Such a self-diffraction action, resulting from SPM in space, is responsible for the well-known nonlinear optical phenomena of self-focusing and self-defocusing (Marburger, 1975; Shen, 1975). It can give rise to a multiple ring structure in the diffracted beam if the SPM is sufficiently strong (Durbin et al., 1981; Santamato and Shen, 1984). In the case of a pulsed laser input, the temporal variation of the laser intensity leads to an SPM in time. Since the time derivative of the phase of a wave is simply the angular frequency of the wave, SPM also appears as a frequency modulation. Thus, the output beam appears with a self-induced spectral broadening (Cheung et al., 1968; Gustafson et al., 1969; Shimizu, 1967).

  7. Voigt Size-Strain Broadening Of Pd Thin Films

    Directory of Open Access Journals (Sweden)

    Vladimir Zucha

    2004-01-01

    Full Text Available Pd thin films were deposited onto Si (100 and glass/Pd/etching substrates by means of r.f. reactive sputtering under the same sputtering condition in order to appreciate the influence of substrate structure. The aim of this study was to appreciate the main X-ray diffraction line profile characteristic by the approximation method. As an approximation function was used the Voigt profile which was calculated by convolution of Gaussian and Cauchy profiles. As an instrumental standart was used ceramic Al2O3 from Nist. Results of size-strain analysis was obtained according to Langford method for one diffraction line and method suggested by Balzar and Ledbetter for two orders of the same diffraction line.

  8. Spectral line-shapes of oxygen B-band transitions measured with cavity ring-down spectroscopy

    International Nuclear Information System (INIS)

    Results of line-shape measurements of self- and N2-broadened P9 P9 transition of the oxygen B band are presented. Spectra were acquired using the optical frequency comb- assisted Pound-Drever-Hall-locked frequency-stabilized cavity ring-down spectrometer (PDH- locked FS-CRDS). In the line-shape analysis the line narrowing described by Dicke narrowing or/and the speed dependence of collisional broadening were taken into account. The multispectrum fitting technique was used to minimize numerical correlations between line-shape parameters. Collisional broadening and shifting coefficients are reported with sub-percent uncertainties. Influence of the spectral line-shape model used in data analysis on determined line intensities and collisional broadening is discussed

  9. Collisional line widths of autoperturbed N2: Measurements and quantum calculations

    International Nuclear Information System (INIS)

    In this work we present new experimental and theoretical values for the line broadening coefficients of the Q-branch Raman lines of autoperturbed N2. For the experimental determination of the coefficients, high resolution stimulated Raman spectra of the Q-branch of N2 at different pressures were obtained at 77, 194 and 298 K. Simultaneously, quantum dynamical calculations, performed on two potential energy surfaces, were carried out for the system between 77 and 298 K, rendering a set of theoretical line broadening coefficients that could be directly compared to those obtained from the present measurements and the previous ones. Within the limit of considering the colliding molecules distinguishable we discuss the ortho and para contributions to the pressure broadening cross-sections. Because such calculations are time consuming we indicate routes to circumvent this difficulty. We observe a reasonable agreement between theoretical and experimental values of the collisional line broadening coefficients at all the studied temperatures.

  10. Interferometric measurement of lines shift in flames in connection with interpretation of lined absorption method in atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    This paper is concerned with interferometric measuring of the line shift in flames in the view of interpretation of absorption lines in the atomic absorption spectroscopy. The newly measured line shifts were compared to the known data on Lorentz broadening of the same lines obtained by methods free of the systematic errors. The resonant lines of the alkaline earth elements (Sr, Ca, Ba) were investigated. To reduce self-absorption in the flame the solutions with minimum concentrations of the elements were used. The computation scheme includes the spectrometer apparatus width and line broadening due to the self-absorption. Formulae are given for computing the values studied. Good agreement was observed between the computed and experimental results. Error analysis was performed. It was concluded that any line shifts in the hydrocarbons were correctly taken into an account in the absolute computations of absorption

  11. Application of Energy Window Concept in Doppler Broadening of 238U Cross Section

    International Nuclear Information System (INIS)

    Currently, the NJOY code is used for construction and Doppler broadening of microscopic cross sections. There exist several methods or formalisms to produce microscopic cross sections and there are also different methods of Doppler broadening. In this paper, Multi-Level Breit-Wigner (MLBW) formalism and the Psi method are used for generation and Doppler broadening of the resonance cross section. Accuracy of the energy window concept applied MLBW (EW MLBW) Doppler broadened cross section was compared with that of the cross section generated by conventional MLBW (Con MLBW) formalism for 238U isotope using MATLAB. The conventional method requires Doppler broadening of all resonances, including resonances far from the target energy point, which do not change much with respect to the temperature change. The energy window concept makes Doppler broadening possible with a smaller number of resonances neighboring to the energy point we are interested in, and just adds up 0 K temperature cross sections of other resonances. Multi-level Breit-Wigner formalism and the Doppler broadening method were used to construct microscopic cross sections of 238U at different temperatures. The energy window concept was applied only for the 1st resonance energy region (4.5∼11.2 eV). The energy window concept demonstrates high competitiveness because the relative differences were less than 0.0016% for all types of cross sections. The advantage of the energy window concept is that the number of resonances broadened for every energy point is significantly reduced, which allows a reduction of computation time by almost 45 % of Doppler broadening time of the cross section generation at temperatures higher than 0 K

  12. Doppler Broadening Calculations of Compton Scattering for Molecules, Plastics, Tissues, and Few Biological Materials in the X-Ray Region: An Analysis in Terms of Compton Broadening and Geometrical Energy Broadening

    Science.gov (United States)

    Rao, D. V.; Cesareo, R.; Brunetti, A.; Gigante, G. E.; Akatsuka, T.; Takeda, T.; Itai, Y.

    2004-09-01

    Relativistic and nonrelativistic Compton profile cross sections for H, C, N, O, P, and Ca and for a few important biological materials such as water, polyethylene, lucite, polystyrene, nylon, polycarbonate, bakelite, fat, bone and calcium hydroxyapatite are estimated for a number of Kα x-ray energies and for 59.54 keV (Am-241) γ photons. Energy broadening and geometrical broadening (ΔG) is estimated by assuming θmin and θmax are symmetrically situated around θ=90°. FWHM of J(PZ) and FWHM of Compton energy broadening are evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 and 1.0 keV for 59.54 keV photons. Total Compton, individual shell, and Compton energy-absorption scattering cross sections are evaluated in the energy region from 0.005 to 0.5 MeV. It is an attempt to know the effect of Doppler broadening for single atoms, many of which constitute the biological materials.

  13. Doppler broadening calculations of Compton scattering for molecules, plastics, tissues, and few biological materials in the X-ray region: An analysis in terms of Compton broadening and geometrical energy broadening

    International Nuclear Information System (INIS)

    Relativistic and nonrelativistic Compton profile cross sections for H, C, N, O, P, and Ca and for a few important biological materials such as water, polyethylene, lucite, polystyrene, nylon, polycarbonate, bakelite, fat, bone and calcium hydroxyapatite are estimated for a number of Kα x-ray energies and for 59.54 keV (Am-241) γ photons. Energy broadening and geometrical broadening (ΔG) is estimated by assuming θmin and θmax are symmetrically situated around θ=90 deg. FWHM of J(PZ) and FWHM of Compton energy broadening are evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 and 1.0 keV for 59.54 keV photons. Total Compton, individual shell, and Compton energy-absorption scattering cross sections are evaluated in the energy region from 0.005 to 0.5 MeV. It is an attempt to know the effect of Doppler broadening for single atoms, many of which constitute the biological materials

  14. Anomalous spectral lines and relic quantum nonequilibrium

    CERN Document Server

    Underwood, Nicolas G

    2016-01-01

    We describe general features that might be observed in the line spectra of relic cosmological particles should quantum nonequilibrium be preserved in their statistics. According to our arguments, these features would represent a significant departure from those of a conventional origin. Among other features, we find a possible spectral broadening (for incident photons) that is proportional to the energy resolution of the recording telescope (and so could be orders of magnitude larger than any intrinsic broadening). Notably, for a range of possible initial conditions we find the possibility of spectral line `narrowing' whereby a telescope could observe a spectral line which is narrower than it should conventionally be able to resolve. We briefly discuss implications for the indirect search for dark matter.

  15. Interference effects and Stark broadening in XUV intrashell transitions in aluminum under conditions of intense XUV free-electron-laser irradiation

    Science.gov (United States)

    Galtier, E.; Rosmej, F. B.; Calisti, A.; Talin, B.; Mossé, C.; Ferri, S.; Lisitsa, V. S.

    2013-03-01

    Quantum mechanical interference effects in the line broadening of intrashell transitions are investigated for dense plasma conditions. Simulations that involved LSJ-split level structure and intermediate coupling discovered unexpected strong line narrowing for intrashell transitions L-L while M-L transitions remained practically unaffected by interference effects. This behavior allows a robust study of line narrowing in dense plasmas. Simulations are carried out for XUV transitions of aluminum that have recently been observed in experiments with the FLASH free-electron laser in Hamburg irradiating solid aluminum samples with intensities greater than 1016 W/cm2. We explore the advantageous case of Al that allows, first, simultaneous observation of M-L transitions and L-L intrashell transitions with high-resolution grating spectrometers and, second, has a convenient threshold to study interference effects at densities much below solid. Finally, we present simulations at near solid density where the line emission transforms into a quasicontinuum.

  16. Evolution of low-frequency features in the CMB spectrum due to stimulated Compton scattering and Doppler-broadening

    CERN Document Server

    Chluba, J

    2008-01-01

    We discuss a new solution of the Kompaneets-equation for physical situations in which low frequency photons, forming relatively narrow spectral details, are Compton scattered in an isotropic, infinite medium with an intense ambient blackbody field that is very close to full thermodynamic equilibrium with the free electrons. In this situation the background-induced stimulated Compton scattering slows down the motion of photons toward higher frequencies by a factor of 3 in comparison with the solution that only takes into account Doppler-broadening and boosting. This new solution is important for detailed computations of cosmic microwave background spectral distortions arising due to uncompensated atomic transitions of hydrogen and helium in the early Universe. In addition we derive another analytic solution that only includes the background-induced stimulated Compton scattering and is valid for power-law ambient radiation fields. This solution might have interesting applications for radio lines arising inside ...

  17. High-resolution spectroscopy for Doppler-broadening ion temperature measurements of implosions at the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J. A.; Stewart, R. E.; Beiersdorfer, P.; Shepherd, R.; Schneider, M. B.; Miles, A. R.; Scott, H. A.; Smalyuk, V. A.; Hsing, W. W. [Lawrence Livermore National Laboratory, P.O. Box 808, L-493, Livermore, California 94550 (United States)

    2012-10-15

    Future implosion experiments at the national ignition facility (NIF) will endeavor to simultaneously measure electron and ion temperatures with temporal and spatial resolution in order to explore non-equilibrium temperature distributions and their relaxation toward equilibrium. In anticipation of these experiments, and with understanding of the constraints of the NIF facility environment, we have explored the use of Doppler broadening of mid-Z dopant emission lines, such as krypton He-{alpha} at 13 keV, as a diagnostic of time- and potentially space-resolved ion temperature. We have investigated a number of options analytically and with numerical raytracing, and we have identified several promising candidate spectrometer designs that meet the expected requirements of spectral and temporal resolution and data signal-to-noise ratio for gas-filled exploding pusher implosions, while providing maximum flexibility for use on a variety of experiments that potentially include burning plasma.

  18. High-resolution spectroscopy for Doppler-broadening ion temperature measurements of implosions at the National Ignition Facilitya)

    Science.gov (United States)

    Koch, J. A.; Stewart, R. E.; Beiersdorfer, P.; Shepherd, R.; Schneider, M. B.; Miles, A. R.; Scott, H. A.; Smalyuk, V. A.; Hsing, W. W.

    2012-10-01

    Future implosion experiments at the national ignition facility (NIF) will endeavor to simultaneously measure electron and ion temperatures with temporal and spatial resolution in order to explore non-equilibrium temperature distributions and their relaxation toward equilibrium. In anticipation of these experiments, and with understanding of the constraints of the NIF facility environment, we have explored the use of Doppler broadening of mid-Z dopant emission lines, such as krypton He-α at 13 keV, as a diagnostic of time- and potentially space-resolved ion temperature. We have investigated a number of options analytically and with numerical raytracing, and we have identified several promising candidate spectrometer designs that meet the expected requirements of spectral and temporal resolution and data signal-to-noise ratio for gas-filled exploding pusher implosions, while providing maximum flexibility for use on a variety of experiments that potentially include burning plasma.

  19. High-resolution spectroscopy for Doppler-broadening ion temperature measurements of implosions at the National Ignition Facility.

    Science.gov (United States)

    Koch, J A; Stewart, R E; Beiersdorfer, P; Shepherd, R; Schneider, M B; Miles, A R; Scott, H A; Smalyuk, V A; Hsing, W W

    2012-10-01

    Future implosion experiments at the national ignition facility (NIF) will endeavor to simultaneously measure electron and ion temperatures with temporal and spatial resolution in order to explore non-equilibrium temperature distributions and their relaxation toward equilibrium. In anticipation of these experiments, and with understanding of the constraints of the NIF facility environment, we have explored the use of Doppler broadening of mid-Z dopant emission lines, such as krypton He-α at 13 keV, as a diagnostic of time- and potentially space-resolved ion temperature. We have investigated a number of options analytically and with numerical raytracing, and we have identified several promising candidate spectrometer designs that meet the expected requirements of spectral and temporal resolution and data signal-to-noise ratio for gas-filled exploding pusher implosions, while providing maximum flexibility for use on a variety of experiments that potentially include burning plasma. PMID:23126948

  20. Hydrogen cycling induced diffraction peak broadening in C14 and C15 Laves phases

    International Nuclear Information System (INIS)

    The diffraction peak broadening induced by hydrogen absorption-desorption cycling has been analyzed in four different Laves phase compounds with the C14 and C15 structures. The broadening is due to strain most probably originating from dislocations generated at the interface between the α and β hydride phases in connection with the cell volume difference between the two phases. It has been shown that it is strongly compound dependent. In the case of the C14 structure, the broadening is large and isotropic, and the latter can be related to the isotropy of the elastic constants of the metallic phase. The broadening is less for the compounds with the C15 structure, which can be related to a possibly softer lattice. Better ageing properties after long-term cycling are predicted for this crystal structure

  1. A universal equation for computing the beam broadening of incident electrons in thin films.

    Science.gov (United States)

    Gauvin, Raynald; Rudinsky, Samantha

    2016-08-01

    A universal equation for computing the beam broadening of incident electrons in thin films is presented. This equation is based on the concepts of anomalous diffusion with the Hurst exponent H. When the thickness to elastic mean free path ratio, t/λ, is greater than 1, the Hurst exponent goes to 0.5 and this random walk behavior leads to the Goldstein et al. [1] beam broadening equation when non-relativistic screened Rutherford elastic cross-sections are used. When t/λ≪1, the lack of elastic collisions for the electron trajectories gives an H exponent of 1 and a different beam broadening equation is obtained. A general equation to compute the beam broadening that takes into account the variation of H with t/λ is presented and this equation was fitted and validated with Monte Carlo simulations of electron trajectories in thin films. PMID:27161415

  2. Smile to see the forest: Facially expressed positive emotions broaden cognition.

    Science.gov (United States)

    Johnson, Kareem J; Waugh, Christian E; Fredrickson, Barbara L

    2010-02-19

    The broaden hypothesis, part of Fredrickson's (1998, 2001) broaden-and-build theory, proposes that positive emotions lead to broadened cognitive states. Here, we present evidence that cognitive broadening can be produced by frequent facial expressions of positive emotion. Additionally, we present a novel method of using facial electromyography (EMG) to discriminate between Duchenne (genuine) and non-Duchenne (non-genuine) smiles. Across experiments, Duchenne smiles occurred more frequently during positive emotion inductions than neutral or negative inductions. Across experiments, Duchenne smiles correlated with self-reports of specific positive emotions. In Experiment 1, high frequencies of Duchenne smiles predicted increased attentional breadth on a global-local visual processing task. In Experiment 2, high frequencies of Duchenne smiles predicted increased attentional flexibility on a covert attentional orienting task. These data underscore the value of using multiple methods to measure emotional experience in studies of emotion and cognition. PMID:23275681

  3. A unified numerical model of collisional depolarization and broadening rates due to hydrogen atom collisions

    CERN Document Server

    Derouich, M; Barklem, P S

    2015-01-01

    Interpretation of solar polarization spectra accounting for partial or complete frequency redistribution requires data on various collisional processes. Data for depolarization and polarization transfer are needed but often missing, while data for collisional broadening are usually more readily available. Recent work by Sahal-Br\\'echot and Bommier concluded that despite underlying similarities in the physics of collisional broadening and depolarization processes, relationships between them are not possible to derive purely analytically. We aim to derive accurate numerical relationships between the collisional broadening rates and the collisional depolarization and polarization transfer rates due to hydrogen atom collisions. Such relationships would enable accurate and efficient estimation of collisional data for solar applications. Using earlier results for broadening and depolarization processes based on general (i.e. not specific to a given atom), semi-classical calculations employing interaction potentials...

  4. Effects of positive mood on attention broadening for self-related information

    OpenAIRE

    Grol, Maud; Koster, Ernst; Bruyneel, Lynn; Raedt, Rudi

    2014-01-01

    Studies on cognitive effects of positive emotions have associated positive emotions to broadened attention. Given the widely investigated relationship between self-focused attention and mood, it is important to investigate the effect of positive mood on visuospatial attention for self-related information. We used a performance-based measure to assess fluctuations in attentional broadening from self-related contrasted to not-self-related information. In Experiment 1, we checked that the self-r...

  5. Positive emotions broaden the scope of attention and thought-action repertoires

    OpenAIRE

    Fredrickson, Barbara L; Branigan, Christine

    2005-01-01

    The broaden-and-build theory (Fredrickson, 1998, 2001) hypothesises that positive emotions broaden the scope of attention and thought-action repertoires. Two experiments with 104 college students tested these hypotheses. In each, participants viewed a film that elicited (a) amusement, (b) contentment, (c) neutrality, (d) anger, or (e) anxiety. Scope of attention was assessed using a global-local visual processing task (Experiment 1) and thought-action repertoires were assessed using a Twenty ...

  6. Experimental measurements of Doppler broadening of escape peaks in HPGe detectors

    International Nuclear Information System (INIS)

    Single-escape, double-escape, and annihilation peak widths from eleven spectra taken with differing HPGe coaxial detectors and differing primary gamma sources were measured. For each of these, the Doppler broadening component of the peak width was derived. Significant Doppler broadening was observed only in the single escape peak and in the annihilation peak width. Averaged values and their uncertainties useful for modeling each type of peak width in nuclear radiation spectra are presented. (author)

  7. Reducing the impact of inhomogeneous broadening on quantum dot based electromagnetically induced transparency

    DEFF Research Database (Denmark)

    Hansen, Per Lunnemann; Mørk, Jesper

    2009-01-01

    Slow light based on electromagnetically induced transparency in an inhomogeneously broadened quantum dot medium is investigated theoretically. Three schemes, , V, and Λ, are compared and it is shown that the V-scheme gives a group velocity that is more than three orders of magnitude smaller compa...... compared to the - and Λ-schemes. The physical mechanisms that make the V-scheme less vulnerable to inhomogeneous broadening are analyzed and discussed...

  8. Network Broadening and Reinforcing for Facilitating Innovation: Value creation networks in the Japanese music industry (Japanese)

    OpenAIRE

    INOUE Tatsuhiko; NAGAYAMA Susumu

    2012-01-01

    This study shows empirical research regarding the value creation network as it relates to facilitating product innovation. What kind of influence does "network broadening" with new players or "network reinforcing" with existing players have on value creation and innovation generation? Furthermore, what kind of environmental change causes network reinforcing and network broadening? This paper attempts a network analysis of the Japanese music industry; a case considered to be at the forefront e...

  9. Analysis of compressive failure of layered materials by kink band broadening

    DEFF Research Database (Denmark)

    Jensen, Henrik Myhre

    1999-01-01

    Failure by steady state kink band broadening in uni-directional fibre composites or layered materials is analysed. An incremental scheme for calculation of kink band broadening stresses and lock-up conditions in the band for arbitrary material behaviour is presented. The method is illustrated by...... material data which are representative for polymer matrix composites for which experimental work exists. (C) 1999 Elsevier Science Ltd. All rights reserved....

  10. Molecular weight distribution broadening of polypropylene by periodic switching of hydrogen and catalyst additions

    OpenAIRE

    Ali, M. Al-Haj; Stroomer, J.; Betlem, B.; Weickert, G.; Roffel, B.

    2008-01-01

    This study presents a feasibility study of the broadening of the polypropylene molecular weight distribution produced using a multisite Ziegler-Natta catalyst in a continuous liquid-pool polymerization reactor. The broadening is achieved by operating the reactor under periodic forcing of both hydrogen and catalyst feed flows. Model-based dynamic optimization is used to determine the cycle period and peak width for these inputs. Through simulation it is shown that limited widening (similar to ...

  11. Effects of broadening on BCS theory in the presence of Van Hove singularities

    International Nuclear Information System (INIS)

    There have been recent suggestions that high-Tc superconductivity can be understood in terms of conventional BCS theory if there is a logarithmic Van Hove singularity in the electron density of states near the Fermi energy as suggested by band theory. We consider the effects of broadening of the singularity on theories of this type. The broadening may be caused by inhomogeneities arising from doping or structural defects, electron inelastic scattering, and three-dimensional dispersion

  12. Photon storage in Λ-type optically dense atomic media. III. Effects of inhomogeneous broadening

    International Nuclear Information System (INIS)

    In a recent paper [Gorshkov et al., Phys. Rev. Lett. 98, 123601 (2007)] and in the two preceding papers [Gorshkov et al., this issue, Phys. Rev. A 76, 033804 (2006); 76, 033805 (2006)], we used a universal physical picture to optimize and demonstrate equivalence between a wide range of techniques for storage and retrieval of photon wave packets in homogeneously broadened Λ-type atomic media, including the adiabatic reduction of the photon group velocity, pulse-propagation control via off-resonant Raman techniques, and photon-echo-based techniques. In the present paper, we generalize this treatment to include inhomogeneous broadening. In particular, we consider the case of Doppler-broadened atoms and assume that there is a negligible difference between the Doppler shifts of the two optical transitions. In this situation, we show that, at high enough optical depth, all atoms contribute coherently to the storage process as if the medium were homogeneously broadened. We also discuss the effects of inhomogeneous broadening in solid state samples. In this context, we discuss the advantages and limitations of reversing the inhomogeneous broadening during the storage time, as well as suggest a way for achieving high efficiencies with a nonreversible inhomogeneous profile

  13. Analysis of pressure-broadened ozone spectra in the 3 micron region

    Science.gov (United States)

    Prochaska, Eleanor S.

    1990-01-01

    The Molecular Spectroscopy Lab at NASA-Langley has been involved in a long term effort to carefully characterize the infrared spectra of small molecules of atmospheric interest, including methane, water vapor, ozone, and their isotopic counterparts. High resolution gas phase infrared spectra are obtained using both a tunable diode laser system, and the McMath Fourier transform spectrometer at the Kitt Peak Solar Observatory. Spectra are obtained at various pressures and temperatures for pure gas samples, and for samples containing mixtures of the species of interest in nitrogen, oxygen, or air. From these spectra, using a nonlinear least squares fitting technique, spectral parameters of position, intensity, and half-width were determined for varying laboratory conditions that approximate atmospheric conditions experienced in remote sensing situations. These parameters are of interest in theoretical studies of these species, as well as in allowing more accurate interpretation of remote sensing data. The current work involves the analysis of a series of McMath FTIR spectra of ozone broadened by mixing with air, nitrogen, or oxygen. Each spectrum covers the region from 2396 to 4057/cm. Each vibrational band is analyzed by first diving its region into small intervals containing a few well isolated absorption lines of reasonable intensity. Each of these small intervals is fit by multiple iterations of the nonlinear least square program until residuals are minimized to a reasonable value which corresponds to the noise level of the measured spectrum. Intervals for the 3 nu(sub 3) ozone band in the region from 3000 to 3060 wavenumbers are being examined.

  14. A broad-standard technique for correcting for band broadening in size-exclusion chromatography.

    Science.gov (United States)

    Zhang, Peng; Mazoyer, Paul; Gilbert, Robert G

    2016-04-22

    Band broadening in size-exclusion chromatography (SEC) is always present to some extent. Broadening effects on averages such as the weight- and number average molecular weights (MW¯ and Mn¯ respectively) are minimal with modern SEC systems. However, broadening distorts the shape of the true molecular weight distribution (MWD), which causes problems if one wants to compare the detailed form of the MWD to a model. An addition to current methods for overcoming this problem is presented. One starts with a sufficiently wide range of samples whose exact values of Mn¯ andMW¯ have been measured by non-SEC methods (e.g. by fluorimetry and light scattering, respectively, of the sample without size separation). A true (unbroadened) molecular weight distribution for a sample can be obtained by deconvolution (here using a maximum-entropy algorithm) by fitting SEC data for these samples to these exact Mn¯ and MW¯ values to find the values of the parameters in a sufficiently flexible assumed broadening function. This was modelled using simulated band broadening and subsequent deconvolution, with the broadening parameters least-squares fitted to the "exact" sets of values of Mn¯ and MW¯. The results show that if these Mn¯ and MW¯ values are for a series of broad (not narrow) standards covering a sufficient range of molecular weight, then after deconvolution, a good representation of the original molecular weight distribution used in the simulation is obtained. The method should prove useful for water-soluble polymers, for which it is often difficult to obtain narrow standards of a wide range of molecular weight, as required in a number of well-established methods for correcting for band broadening. PMID:27016112

  15. Multispectrum analysis of the ν9 band of 12C2H6: Positions, intensities, self- and N2-broadened half-width coefficients

    International Nuclear Information System (INIS)

    Line positions, intensities, Lorentz self- and N2-broadened half-width coefficients have been measured for PQ3, PQ2, PQ1, RQ0, RQ1, RQ2, and RQ3 sub-band transitions in the ν9 fundamental band of 12C2H6. A multispectrum nonlinear least-squares fitting technique was used to fit up to 17 high-resolution (∼0.00156 cm-1), room temperature absorption spectra of pure (99.99% chemical purity) natural sample of ethane and lean mixtures of the high-purity ethane diluted with N2. A Bruker IFS 120HR Fourier transform spectrometer located at the Pacific Northwest National Laboratory (PNNL), in Richland, Washington was used to record the data. A standard Voigt line shape was assumed to fit all the data since no line mixing or other non Voigt line shapes were required to fit any of the spectra used in the analysis. Short spectral intervals (∼2-2.5 cm-1) of all 17 spectra covering a specific PQ or RQ sub-band were fit simultaneously. For the first time in an ethane band, pressure-broadened half-width coefficients were determined for the torsional-split components. However, for better reliability of the retrieved coefficients for the weaker components (transitions with large intensity ratios of 4:1 or 3:1 for most K levels between the strong and weak components), constraints were used such that the half-width coefficients of both torsional-split components for a given J were identical for a specific broadening gas. No pressure-induced shift coefficients were necessary to fit the spectra to their noise level. The present study revealed for the first time the dependence of self- and N2-broadened half-width coefficients upon the J, K quantum numbers of the transitions in ethane. A number of transitions belonging to the ν9+ν4-ν4 and the ν9+2ν4-2ν4 hot bands were also observed in the fitted regions and measurements were made when possible.

  16. Effect of Surface Adsorption on Temporal and Spatial Broadening in Micro Free Flow Electrophoresis.

    Science.gov (United States)

    Geiger, Matthew; Harstad, Rachel K; Bowser, Michael T

    2015-12-01

    Analyte adsorption onto surfaces presents a challenge for many separations, often becoming a significant source of peak broadening and asymmetry. We have shown that surface adsorption has no effect on peak position or spatial broadening in micro free flow electrophoresis (μFFE) separations. Surface adsorption does affect the time it takes an analyte to travel through the μFFE separation channel and therefore contributes to temporal broadening. These results were confirmed using μFFE separations of fluorescein, rhodamine 110, and rhodamine 123 in a low ionic strength buffer to promote surface adsorption. Peak widths and asymmetries were measured in both the temporal and spatial dimensions. Under these conditions rhodamine 123 exhibited significant interactions with the separation channel surface, causing increased peak broadening and asymmetry in the temporal dimension. Broadening or asymmetry in the spatial dimension was not significantly different than that of fluorescein, which did not interact with the capillary surface. The effect of strong surface interactions was assessed using μFFE separations of Chromeo P503 labeled myoglobin and cytochrome c. Myoglobin and cytochrome c were well resolved and gave rise to symmetrical peaks in the spatial dimension even under conditions where permanent adsorption onto the separation channel surface occurred. PMID:26496470

  17. Implementation of On-the-Fly Doppler Broadening in MCNP5 for Multiphysics Simulation of Nuclear Reactors

    Energy Technology Data Exchange (ETDEWEB)

    William Martin

    2012-11-16

    A new method to obtain Doppler broadened cross sections has been implemented into MCNP, removing the need to generate cross sections for isotopes at problem temperatures. Previous work had established the scientific feasibility of obtaining Doppler-broadened cross sections "on-the-fly" (OTF) during the random walk of the neutron. Thus, when a neutron of energy E enters a material region that is at some temperature T, the cross sections for that material at the exact temperature T are immediately obtained by interpolation using a high order functional expansion for the temperature dependence of the Doppler-broadened cross section for that isotope at the neutron energy E. A standalone Fortran code has been developed that generates the OTF library for any isotope that can be processed by NJOY. The OTF cross sections agree with the NJOY-based cross sections for all neutron energies and all temperatures in the range specified by the user, e.g., 250K - 3200K. The OTF methodology has been successfully implemented into the MCNP Monte Carlo code and has been tested on several test problems by comparing MCNP with conventional ACE cross sections versus MCNP with OTF cross sections. The test problems include the Doppler defect reactivity benchmark suite and two full-core VHTR configurations, including one with multiphysics coupling using RELAP5-3D/ATHENA for the thermal-hydraulic analysis. The comparison has been excellent, verifying that the OTF libraries can be used in place of the conventional ACE libraries generated at problem temperatures. In addition, it has been found that using OTF cross sections greatly reduces the complexity of the input for MCNP, especially for full-core temperature feedback calculations with many temperature regions. This results in an order of magnitude decrease in the number of input lines for full-core configurations, thus simplifying input preparation and reducing the potential for input errors. Finally, for full-core problems with multiphysics

  18. Self-referencing of an on-chip soliton Kerr frequency comb without external broadening

    CERN Document Server

    Brasch, Victor; Jost, John D; Geiselmann, Michael; Kippenberg, Tobias J

    2016-01-01

    Self-referencing turns pulsed laser systems into self-referenced frequency combs. Such frequency combs allow counting of optical frequencies and have a wide range of applications. The required optical bandwidth to implement self-referencing is typically obtained via nonlinear broadening in optical fibers. Recent advances in the field of Kerr frequency combs have provided a path towards the development of compact frequency comb sources that provide broadband frequency combs, exhibit microwave repetition rates and that are compatible with on-chip photonic integration. These devices have the potential to significantly expand the use of frequency combs. Yet to date self-referencing of such Kerr frequency combs has only been attained by applying conventional, fiber based broadening techniques. Here we demonstrate external broadening-free self-referencing of a Kerr frequency comb. An optical spectrum that spans two-thirds of an octave is directly synthesized from a continuous wave laser-driven silicon nitride micro...

  19. Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials

    International Nuclear Information System (INIS)

    Neutron diffraction is an essential tool in the study of internal stresses in composite materials. In most work only the peak shifts caused by the related elastic strains are considered, but other valuable information exists in the form of peak shape changes. The conditions under which the pure diffraction profile of the composite (i.e. the profile when all sources of broadening not caused by the residual stresses are removed) represents the probability distribution of the peak shifts corresponding to the strains are examined. It is shown that in these conditions, the pure diffraction profile has no attributes of particle size broadening (and vice versa), thereby providing a test for the validity of results interpreted in this way. The experimental derivation of measured strain distributions in Al2O3/SiCp composites using neutron diffraction is described. No apparent particle size broadening was detected, demonstrating the validity of the results, which also satisfied other tests for consistency

  20. The effect of Kerr nonlinearity and Doppler broadening on slow light propagation

    International Nuclear Information System (INIS)

    The influence of Kerr nonlinearity and Doppler broadening on the slow light propagation of a dispersive atomic medium is revisited using a four-level Λ-type (87Rb) atomic system under the condition of electromagnetically induced transparency (EIT). The medium exhibits an EIT process which is accompanied by normal dispersion, i.e., sub-luminal (slow light) pulse propagation. In the presence of Kerr nonlinearity and the Doppler broadening effect the dispersion property of the proposed atomic medium is modified, which leads to enhancement of the positive group index of the medium. The combined effect of Kerr nonlinearity and Doppler broadening on slow light propagation inside the medium is the major motivation for this work. (paper)

  1. Gamma-ray emission spectrum from thermonuclear fusion reactions without intrinsic broadening

    DEFF Research Database (Denmark)

    Nocente, M.; Källne, J.; Salewski, Mirko;

    2015-01-01

    First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution instrume......First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution...... information that can be extracted from the gamma-ray emission spectrum of fusion reactions without intrinsic broadening and are of relevance for applications to high performance plasmas of present and next generation devices....

  2. Ghost features in Doppler-broadened spectra of rovibrational transitions in trapped HD$^+$ ions

    CERN Document Server

    Patra, Sayan

    2016-01-01

    Doppler broadening plays an important role in laser rovibrational spectroscopy of trapped deuterated molecular hydrogen ions (HD$^+$), even at the millikelvin temperatures achieved through sympathetic cooling by laser-cooled beryllium ions. Recently, Biesheuvel \\textit{et al.} \\cite{Biesheuvel2016} presented a theoretical lineshape model for such transitions which not only considers linestrengths and Doppler broadening, but also the finite sample size and population redistribution by blackbody radiation, which are important in view of the long storage and probe times achievable in ion traps. Here, we employ the rate equation model developed by Biesheuvel \\textit{et al.} to theoretically study the Doppler-broadened hyperfine structure of the $(v,L):(0,3)\\rightarrow(4,2)$ rovibrational transition in HD$^+$ at 1442~nm. We observe prominent yet hitherto unrecognized ghost features in the simulated spectrum, whose positions depend on the Doppler width, transition rates, and saturation levels of the hyperfine compo...

  3. Influence of gamma rays colimation on Mosbauer lines

    International Nuclear Information System (INIS)

    The effect of gamma rays collimation in Mossbauer absorption spectra was investigated when thin absorbers are used. A simple model is proposed to study shift and broadening of spectral lines. This model along with some approximations, makes the calculations easily done. The results are in good agreement with those in the literature. (author)

  4. The Second Workshop on Lineshape Code Comparison: Isolated Lines

    Directory of Open Access Journals (Sweden)

    Spiros Alexiou

    2014-05-01

    Full Text Available In this work, we briefly summarize the theoretical aspects of isolated line broadening. We present and discuss test run comparisons from different participating lineshape codes for the 2s-2p transition for LiI, B III and NV.

  5. Single photon quantum non-demolition measurements in the presence of inhomogeneous broadening

    International Nuclear Information System (INIS)

    Electromagnetically induced transparency (EIT) has often been proposed for generating nonlinear optical effects at the single photon level; in particular, as a means to effect a quantum non-demolition measurement of a single-photon field. Previous treatments have usually considered homogeneously broadened samples, but realizations in any medium will have to contend with inhomogeneous broadening. Here we reappraise an earlier scheme (Munro et al 2005 Phys. Rev. A 71 033819) with respect to inhomogeneities and show an alternative mode of operation that is preferred in an inhomogeneous environment. We further show the implications of these results on a potential implementation in diamond-containing nitrogen-vacancy colour centres.

  6. Acousto-optics bandwidth broadening in a Bragg cell based on arbitrary synthesized signal methods.

    Science.gov (United States)

    Peled, Itay; Kaminsky, Ron; Kotler, Zvi

    2015-06-01

    In this work, we present the advantages of driving a multichannel acousto-optical deflector (AOD) with a digitally synthesized multifrequency RF signal. We demonstrate a significant bandwidth broadening of ∼40% by providing well-tuned phase control of the array transducers. Moreover, using a multifrequency, complex signal, we manage to suppress the harmonic deflections and return most of the spurious energy to the main beam. This method allows us to operate the AOD with more than an octave of bandwidth with negligible spurious energy going to the harmonic beams and a total bandwidth broadening of over 70%. PMID:26192666

  7. Effect of PMD-induced Pulse Broadening on Sensitivity and Frequency Spectrum

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The PMD-induced pulse broadening may cause the degradation of receiver sensitivity and has negative effects on the power spectrum of received signals. The expressions of PMD-induced pulse broadening effects on receiver sensitivity are derived based on the concept of mean square pulse width. The effects of PMD on the spectrum of received power are analyzed in detail. Finally, the scheme is discussed with which the power of a certain frequency component is extracted as a feedback control signal in a PMD compensation system.

  8. The density broadening in a sodium F=2 condensate detected by a pulse train

    Directory of Open Access Journals (Sweden)

    Jianing Han

    2011-09-01

    Full Text Available The dipole-blockaded sodium clock transition has been detected by high resolution microwave spectroscopy, the multiple-pulse spectroscopy. This spectroscopic technique has been first used to detect the density broadening and shifting in a Sodium Bose Einstein Condensate (BEC by probing the sodium clock-transition. Moreover, by narrowing the pulse-width of the pulses, some of the broadening mechanisms can be partially reduced. The results reported here are essential steps toward the ground-state quantum computing, few-body spectroscopy, spin squeezing and quantum metrology.

  9. Enhancement of self-phase modulation induced spectral broadening in silicon suspended membrane waveguides

    Science.gov (United States)

    Zhang, Yaojing; Cheng, Zhenzhou; Liu, Linghai; Zhu, Bingqing; Wang, Jiaqi; Zhou, Wen; Wu, Xinru; Tsang, Hon Ki

    2016-05-01

    We experimentally observed a possibly enhanced self-phase modulation (SPM) in silicon suspended membrane waveguides (SMWs) by measuring the spectral broadening of optical pulses. The nonlinear coefficient n 2 and the two-photon absorption coefficient β 2 of silicon SMWs were measured to be (4.6 ± 0.9) × 10-18 m2 W-1 and 0.46 cm GW-1 at 1555 nm wavelength. We also proposed a method of using SPM-induced spectral broadening to obtain the coupling loss of a single grating coupler and experimentally compared the spectra of two grating couplers in silicon SMWs and in silicon-on-insulator waveguides.

  10. Broadening of ICRH produced fast ion profiles due to orbit effects

    International Nuclear Information System (INIS)

    In the JET tokamak, minority ions accelerated by ICRH reach energies in the MeV range. Near the plasma magnetic axis, the standard trapped particle ''banana'' orbit is distorted into a ''potato'' or ''fat banana'' orbit. The zero banana width approximation which is used in most Fokker-Planck calculations of velocity distributions of resonating ions is often not valid in JET. The inclusion of finite banana width effects will, in general, lead to a lowering of the averaged tail energy and a broadening of pressure profiles, power transfer profiles etc. A model for calculating orbit broadened profiles is presented. (Author)

  11. Saturation broadening effect in an InP photonic-crystal nanocavity switch

    DEFF Research Database (Denmark)

    Yu, Yi; Palushani, Evarist; Heuck, Mikkel;

    2014-01-01

    Pump-probe measurements on InP photonic-crystal nanocavities show large-contrast fast switching at low pulse energy. For large pulse energies, large resonance shifts passing across the probe lead to switching contrast saturation and switching time-window broadening. © 2014 OSA.......Pump-probe measurements on InP photonic-crystal nanocavities show large-contrast fast switching at low pulse energy. For large pulse energies, large resonance shifts passing across the probe lead to switching contrast saturation and switching time-window broadening. © 2014 OSA....

  12. Photonic superdiffusive motion in resonance line radiation trapping - partial frequency redistribution effects

    CERN Document Server

    Alves-Pereira, A R; Martinho, J M G; Berberan-Santos, M N

    2007-01-01

    The relation between the jump length probability distribution function and the spectral line profile in resonance atomic radiation trapping is considered for Partial Frequency Redistribution (PFR) between absorbed and reemitted radiation. The single line Opacity Distribution Function [M.N. Berberan-Santos et.al. J.Chem.Phys. 125, 174308 (2006)] is generalized for PFR and used to discuss several possible redistribution mechanisms (pure Doppler broadening, combined natural and Doppler broadening and combined Doppler, natural and collisional broadening). It is shown that there are two coexisting scales with a different behavior: the small scale is controlled by the intricate PFR details while the large scale is essentially given by the atom rest frame redistribution asymptotic. The pure Doppler and combined natural, Doppler and collisional broadening are characterized by both small and large scale superdiffusive Levy flight behaviors while the combined natural and Doppler case has an anomalous small scale behavi...

  13. X-ray diffraction line shapes from bent crystals with linear strain

    International Nuclear Information System (INIS)

    This paper provides an exact solution for the X-ray diffraction line shape from a bent crystal with linear strain. Such crystals may be found along concentration gradients in a diffusion or ion-implanted zone, thin films and cold-worked materials. The solution simplifies into a sum of squares of two pairs of Fresnel integrals which can be evaluated with very little computer time. The limiting cases of both pure particle-size broadening and pure strain broadening are also considered. Instrumental broadening is introduced by a numerical convolution with a Pearson VII function. A method of determining the linear strain and crystal size from experimental data is discussed. (orig.)

  14. Uncovering Tacit Knowledge: A Pilot Study to Broaden the Concept of Knowledge in Knowledge Translation

    Directory of Open Access Journals (Sweden)

    Edwards Nancy

    2011-08-01

    Full Text Available Abstract Background All sectors in health care are being asked to focus on the knowledge-to-practice gap, or knowledge translation, to increase service effectiveness. A social interaction approach to knowledge translation assumes that research evidence becomes integrated with previously held knowledge, and practitioners build on and co-create knowledge through mutual interactions. Knowledge translation strategies for public health have not provided anticipated positive changes in evidence-based practice, possibly due in part to a narrow conceptualization of knowledge. More work is needed to understand the role of tacit knowledge in decision-making and practice. This pilot study examined how health practitioners applied tacit knowledge in public health program planning and implementation. Methods This study used a narrative approach, where teams from two public health units in Ontario, Canada were conveniently selected. Respondents participated in individual interviews and focus groups at each site. Questions were designed to understand the role of tacit knowledge as it related to the program planning process. Data were analyzed through a combination of content analysis and thematic comparison. Results The findings highlighted two major aspects of knowledge that arose: the use of tacit knowledge and the integration of tacit and explicit knowledge. Tacit knowledge included: past experiences, organization-specific knowledge, community contextual knowledge, and the recognition of the tacit knowledge of others. Explicit knowledge included: research literature, the Internet, popular magazines, formal assessments (surveys and interviews, legislation and regulations. Participants sometimes deliberately combined tacit and explicit knowledge sources in planning. Conclusions This pilot demonstrated that front-line public health workers draw upon both tacit knowledge and explicit knowledge in their everyday lived reality. Further, tacit knowledge plays an

  15. Line radiative transfer and statistical equilibrium*

    Directory of Open Access Journals (Sweden)

    Kamp Inga

    2015-01-01

    Full Text Available Atomic and molecular line emission from protoplanetary disks contains key information of their detailed physical and chemical structures. To unravel those structures, we need to understand line radiative transfer in dusty media and the statistical equilibrium, especially of molecules. I describe here the basic principles of statistical equilibrium and illustrate them through the two-level atom. In a second part, the fundamentals of line radiative transfer are introduced along with the various broadening mechanisms. I explain general solution methods with their drawbacks and also specific difficulties encountered in solving the line radiative transfer equation in disks (e.g. velocity gradients. I am closing with a few special cases of line emission from disks: Radiative pumping, masers and resonance scattering.

  16. Broad iron lines in Active Galactic Nuclei

    CERN Document Server

    Fabian, A C; Reynolds, C S; Young, A J

    2000-01-01

    An intrinsically narrow line emitted by an accretion disk around a black hole appears broadened and skewed as a result of the Doppler effect and gravitational redshift. The fluorescent iron line in the X-ray band at 6.4-6.9keV is the strongest such line and is seen in the X-ray spectrum of many active galactic nuclei and, in particular, Seyfert galaxies. It is an important diagnostic with which to study the geometry and other properties of the accretion flow very close to the central black hole. The broad iron line indicates the presence of a standard thin accretion disk in those objects, often seen at low inclination. The broad iron line has opened up strong gravitational effects around black holes to observational study with wide-reaching consequences for both astrophysics and physics.

  17. Submillimeter-wave measurements of N2 and O2 pressure broadening for HO2 radical generated by Hg-photosensitized reaction

    International Nuclear Information System (INIS)

    The N2 and O2 pressure broadening coefficients of the pure rotational transitions at 625.66 GHz (NKaKc=101-9-100-10, J=10.5-10.5) and 649.70 GHz (NKaKc=102-9-92-8, J=9.5-8.5) in the vibronic ground state X2A′ of the perhydroxyl (HO2) radical have been determined by precise laboratory measurements. For the production of HO2, the mercury-photosensitized reaction of the H2 and O2 precursors was used to provide an optimum condition for measurement of the pressure broadening coefficient. The Superconducting Submillimeter-wave Limb Emission Sounder (SMILES) was designed to monitor the volume mixing ratio of trace gases including HO2 in the Earth's upper atmosphere using these transitions. The precise measurement of pressure broadening coefficient γ in terms of the half width at half maximum is required in order to retrieve the atmospheric volume mixing ratio. In this work, γ coefficients of the 625.66 GHz transition were determined for N2 and O2 at room temperature as γ(N2)=4.085±0.049 MHz/Torr and γ(O2)=2.578±0.047 MHz/Torr with 3σ uncertainty. Similarly, the coefficients of the 649.70 GHz transition were determined as γ(N2)=3.489±0.094 MHz/Torr and γ(O2)=2.615±0.099 MHz/Torr. The air broadening coefficients for the 625.66 GHz and 649.70 GHz lines were estimated at γ(air)=3.769±0.067 MHz and 3.298±0.099 MHz respectively, where the uncertainty includes possible systematic errors. The newly determined coefficients are compared with previous results and we discuss the advantage of the mercury-photosensitized reaction for HO2 generation. In comparison with those of other singlet molecules, the pressure broadening coefficients of the HO2 radical are not much affected by the existence of an unpaired electron.

  18. Coupling and ionization effects on hydrogen spectral line shapes in dense plasmas

    Science.gov (United States)

    Calisti, A.; Bureyeva, L. A.; Lisitsa, V. S.; Shuvaev, D.; Talin, B.

    2007-06-01

    A study of hydrogen lines emitted in dense and low temperature plasmas is presented. Coupling and ionization effects in a transition from impact to quasi-static broadening for electrons are analyzed with the help of the Frequency Fluctuation Model (FFM). Electron broadening of Balmer series lines is studied for different densities and temperatures spanning a wide domain from impact to quasi-static limit. It is shown that electronic broadening makes a transition from impact to quasi-static limit depending on plasma conditions and principal quantum number. Even for the Balmer alpha line, at a density equals 1018 cm-3 and a temperature equals 1 eV, this transition occurs both in the wings and the core of the line.

  19. Spectrally resolved four-wave mixing in semiconductors: Influence of inhomogeneous broadening

    DEFF Research Database (Denmark)

    Erland, J.; Pantke, K.-H.; Mizeikis, V.;

    1994-01-01

    We study the influence of inhomogeneous broadening on results obtained from spectrally resolved transient four-wave mixing. In particular, we study the case where more resonances are coherently excited, leading to polarization interference or quantum beats, depending on the microscopic nature of...

  20. High-energy pulse compressor using self-defocusing spectral broadening in anomalously dispersive media

    DEFF Research Database (Denmark)

    Bache, Morten; Zhou, Binbin

    A new high-energy pulse compressor uses self-defocusing spectral broadening in anomalously dispersive quadratic nonlinear crystals, followed by positive group-delay-dispersion compensation. Compression to sub-50 fs is possible from Joule-class 1.03 µm femtosecond amplifiers in large-aperture KDP....

  1. Broadening the definition of resilience and "reappraising" the use of appetitive motivation.

    Science.gov (United States)

    Soenke, Melissa; O'Connor, Mary-Frances; Greenberg, Jeff

    2015-01-01

    Kalisch et al.'s PASTOR model synthesizes current knowledge of resilience, focusing on mechanisms as a common pathway to outcomes and highlighting neuroscience as a method for exploring this. We propose the model broaden its definition of resiliency to include positive indices of recovery, include positive affect as a mechanism, and approach motivation as distinct from overcoming aversive motivation. PMID:26785906

  2. Doppler radar spectral width broadening due to beamwidth and wind shear

    Directory of Open Access Journals (Sweden)

    G. D. Nastrom

    Full Text Available The spectral width observed by Doppler radars can be due to several effects including the atmospheric turbulence within the radar sample volume plus effects associated with the background flow and the radar geometry and configuration. This study re-examines simple models for the effects due to finite beamwidth and vertical shear of the horizontal wind. Analytic solutions of 1- and 2-dimensional models are presented. Comparisons of the simple 2-dimensional model with numerical integrations of a 3-dimensional model with a symmetrical Gaussian beam show that the 2-dimensional model is usually adequate. The solution of the 2-dimensional model gives a formula that can be applied easily to large data sets. Analysis of the analytic solutions of the 2-dimensional model for off-vertical beams reveals a term that has not been included in mathematical formulas for spectral broadening in the past. This term arises from the simultaneous effects of the changing geometry due to curvature within a finite beamwidth and the vertical wind shear. The magnitude of this effect can be comparable to that of the well-known effects of beam-broadening and wind shear, and since it can have either algebraic sign, it can significantly reduce (or increase the expected spectral broadening, although under typical conditions it is smaller than the beam-broadening effect. The predictions of this simple model are found to be consistent with observations from the VHF radar at White Sands Missile Range, NM.

  3. Improving Enzyme Activity and Broadening Selectivity for Biological Desulfurization and Upgrading of Petroleum Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Abhijeet P. Borole; Choo Y. Hamilton; Karen Miller; Brian Davison; Matthew Grossman; Robert Shong

    2003-05-12

    The objective of this project was to develop improved biocatalysts for desulfurization and upgrading of petroleum feedstocks. The goal was to improve the activity and broaden the selectivity of desulfurization enzymes using directed evolution as a tool as well as to explore the impact of ring-opening on biological desulfurization

  4. Pulse Broadening Measurements from the Galactic Center Pulsar J1745--2900

    CERN Document Server

    Spitler, L G; Eatough, R P; Kramer, M; Karuppusamy, R; Bassa, C G; Cognard, I; Desvignes, G; Lyne, A G; Stappers, B W; Bower, G C; Cordes, J M; Champion, D J; Falcke, H

    2013-01-01

    We present temporal scattering measurements of single pulses and average profiles of PSR J1745--2900, a magnetar recently discovered only 3 arcsec away from Sagittarius A* (Sgr A*), from 1.2 - 18.95 GHz using the Effelsberg 100-m Radio Telescope, the Nan\\c{c}ay Decimetric Radio Telescope, and the Jodrell Bank Lovell Telescope. Single pulse analysis shows that the integrated pulse profile above 2 GHz is dominated by pulse jitter, while below 2 GHz the pulse profile shape is dominated by scattering. The high dispersion measure and rotation measure of the magnetar suggest that it is close to Sgr A* (within ~0.1 pc). This is the first object in the GC with both pulse broadening and angular broadening measurements. We measure a pulse broadening spectral index of alpha = -3.8 +/- 0.2 and a pulse broadening time scale at 1 GHz of tau_GHz = 1.3 +/- 0.2 s, which is several orders of magnitude lower than the scattering predicted by the NE2001 model (Cordes and Lazio 2002). If this scattering timescale is representative...

  5. Influence of multiple small-angle neutron scattering on diffraction peak broadening in ferritic steel

    Czech Academy of Sciences Publication Activity Database

    Woo, W.; Em, V.; Shin, E.; Mikula, Pavol; Ryukhtin, Vasyl

    2015-01-01

    Roč. 48, APR (2015), s. 350-356. ISSN 0021-8898 R&D Projects: GA ČR GB14-36566G; GA MŠk(CZ) LM2011019 Institutional support: RVO:61389005 Keywords : peak broadening * small-angle neutron scattering * neutron diffraction * magnetic domain Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.720, year: 2014

  6. Broadening of Plasmonic Resonance Due to Electron Collisions with Nanoparticle Boundary: а Quantum Mechanical Consideration

    DEFF Research Database (Denmark)

    Uskov, Alexander; Protsenko, Igor E.; Mortensen, N. Asger;

    2014-01-01

    We present a quantum mechanical approach to calculate broadening of plasmonic resonances in metallic nanostructures due to collisions of electrons with the surface of the structure. The approach is applicable if the characteristic size of the structure is much larger than the de Broglie electron...

  7. Quantum Memory for Microwave Photons in an Inhomogeneously Broadened Spin Ensemble

    DEFF Research Database (Denmark)

    Julsgaard, Brian; Grezes, Cécile; Bertet, Patrice; Mølmer, Klaus

    2013-01-01

    We propose a multi-mode quantum memory protocol able to store the quantum state of the field in a microwave resonator into an ensemble of electronic spins. The stored information is protected against inhomogeneous broadening of the spin ensemble by spin-echo techniques resulting in memory times...

  8. PROBLEM DEPENDENT DOPPLER BROADENING OF CONTINUOUS ENERGY CROSS SECTIONS IN THE KENO MONTE CARLO COMPUTER CODE

    Energy Technology Data Exchange (ETDEWEB)

    Hart, S. W. D. [University of Tennessee, Knoxville (UTK); Maldonado, G. Ivan [University of Tennessee, Knoxville (UTK); Celik, Cihangir [ORNL; Leal, Luiz C [ORNL

    2014-01-01

    For many Monte Carlo codes cross sections are generally only created at a set of predetermined temperatures. This causes an increase in error as one moves further and further away from these temperatures in the Monte Carlo model. This paper discusses recent progress in the Scale Monte Carlo module KENO to create problem dependent, Doppler broadened, cross sections. Currently only broadening the 1D cross sections and probability tables is addressed. The approach uses a finite difference method to calculate the temperature dependent cross-sections for the 1D data, and a simple linear-logarithmic interpolation in the square root of temperature for the probability tables. Work is also ongoing to address broadening theS (alpha , beta) tables. With the current approach the temperature dependent cross sections are Doppler broadened before transport starts, and, for all but a few isotopes, the impact on cross section loading is negligible. Results can be compared with those obtained by using multigroup libraries, as KENO currently does interpolation on the multigroup cross sections to determine temperature dependent cross-sections. Current results compare favorably with these expected results.

  9. Broaden Engineering Technology students' knowledge through hands-on with motion robotics

    Science.gov (United States)

    The skills and knowledge that employers value most are not always well-aligned with undergraduate engineering technology programs. With the support of a federal grant, we identify and propose to broaden the undergraduate student experience to include training in transferable skills with agricultura...

  10. Attitudes and Motivation of Poor and Good Spellers: Broadening Planned Behavior Theory

    Science.gov (United States)

    Sideridis, Georgios D.

    2005-01-01

    The purpose of the present study was to broaden planned behavior theory and examine its applicability to predict the academic achievement of students of low and high spelling ability. Two hundred fifty seven students, 54 low spellers and 203 high spellers from thirty elementary schools in northern Greece, participated in the study. Between groups…

  11. Mixed Weyl Symbol Calculus and Spectral Line Shape Theory

    OpenAIRE

    Osborn, T. A.; Kondrat'eva, M. F.; Tabisz, G. C.; McQuarrie, B. R.

    1998-01-01

    A new and computationally viable full quantum version of line shape theory is obtained in terms of a mixed Weyl symbol calculus. The basic ingredient in the collision--broadened line shape theory is the time dependent dipole autocorrelation function of the radiator-perturber system. The observed spectral intensity is the Fourier transform of this correlation function. A modified form of the Wigner--Weyl isomorphism between quantum operators and phase space functions (Weyl symbols) is introduc...

  12. Evidence for speed-dependent effects in NH3 self-broadened spectra: towards a new determination of the Boltzmann constant

    CERN Document Server

    Triki, Meriam; Darquié, Benoît; Sow, Papa Lat Tabara; Roncin, Vincent; Chardonnet, Christian; Daussy, Christophe

    2012-01-01

    In this paper we present an accurate analysis of the shape of an isolated rovibrational ammonia line from the strong nu2 band around 10 $\\mu$m, recorded by laser absorption spectroscopy. Experimental spectra obtained under controlled temperature and pressure, are confronted to various models that take into account Dicke narrowing or speed-dependent effects. Our results show clear evidence for speed-dependent broadening and shifting, which had never been demonstrated so far in NH3. Accurate lineshape parameters of the nu2 saQ(6,3) line are obtained. Our current project aiming at measuring the Boltzmann constant, kB, by laser spectroscopy will straight away benefit from such knowledge. We anticipate that a first optical determination of kB with a competitive uncertainty of a few ppm is now reachable.

  13. Stark Broadening of Carbon and Oxygen Lines in Hot DQ White Dwarf Stars: Recent Results and Applications

    OpenAIRE

    Dufour, P.; Nessib, N. Ben; Sahal-Bréchot, S.; Dimitrijević, M. S.

    2011-01-01

    White dwarf stars are traditionally found to have surface compositions made primarily of hydrogen or helium. However, a new family has recently been uncovered, the so-called Hot DQ white dwarfs, which have surface compositions dominated by carbon and oxygen with little or no trace of hydrogen and helium (Dufour et al. 2007, 2008, 2010). Deriving precise atmospheric parameters for these objects (such as the effective temperature and the surface gravity) requires detailed modeling of spectral l...

  14. Measurement of Plasma Ion Temperature and Flow Velocity from Chord-Averaged Emission Line Profile

    Indian Academy of Sciences (India)

    Xu Wei

    2011-03-01

    The distinction between Doppler broadening and Doppler shift has been analysed, the differences between Gaussian fitting and the distribution of chord-integral line shape have also been discussed. Local ion temperature and flow velocity have been derived from the chord-averaged emission line profile by a chosen-point Gaussian fitting technique.

  15. Broadening the Study of Participation in the Life Sciences: How Critical Theoretical and Mixed-Methodological Approaches Can Enhance Efforts to Broaden Participation.

    Science.gov (United States)

    Metcalf, Heather

    2016-01-01

    This research methods Essay details the usefulness of critical theoretical frameworks and critical mixed-methodological approaches for life sciences education research on broadening participation in the life sciences. First, I draw on multidisciplinary research to discuss critical theory and methodologies. Then, I demonstrate the benefits of these approaches for researchers who study diversity and inclusion issues in the life sciences through examples from two critical mixed-methods studies of prominent issues in science, technology, engineering, and mathematics (STEM) participation and recognition. The first study pairs critical discourse analysis of the STEM workforce literature, data, and underlying surveys with quantitative analyses of STEM pathways into the workforce. This example illustrates the necessity of questioning popular models of retention. It also demonstrates the importance of intersecting demographic categories to reveal patterns of experience both within and between groups whose access to and participation in STEM we aim to improve. The second study's critical approach applies research on inequities in prizes awarded by STEM professional societies toward organizational change. This example uses data from the life sciences professional societies to show the importance of placing data within context to broaden participation and understand challenges in creating sustainable change. PMID:27521238

  16. Monte Carlo simulation and gaussian broaden techniques for full energy peak of characteristic X-ray in EDXRF

    International Nuclear Information System (INIS)

    Background: Non-standard analysis (NSA) technique is one of the most important development directions of energy dispersive X-ray fluorescence (EDXRF). Purpose: This NSA technique is mainly based on Monte Carlo (MC) simulation and full energy peak broadening, which were studied preliminarily in this paper. Methods: A kind of MC model was established for Si-PIN based EDXRF setup, and the flux spectra were obtained for iron ore sample. Finally, the flux spectra were broadened by Gaussian broaden parameters calculated by a new method proposed in this paper, and the broadened spectra were compared with measured energy spectra. Results: MC method can be used to simulate EDXRF measurement, and can correct the matrix effects among elements automatically. Peak intensities can be obtained accurately by using the proposed Gaussian broaden technique. Conclusions: This study provided a key technique for EDXRF to achieve advanced NSA technology. (authors)

  17. Turbulence in Clusters of Galaxies and X-Ray Line Profiles

    CERN Document Server

    Inogamov, N A

    2003-01-01

    Large-scale bulk motions and hydrodynamic turbulence in the intergalactic gas inside clusters of galaxies significantly broaden X-ray emission lines. For lines of heavy ions (primarily helium-like and hydrogen-like iron ions), the hydrodynamic broadening is significantly larger than the thermal broadening. Since cluster of galaxies have a negligible optical depth for resonant scattering in forbidden and intercombination lines of these ions, these lines are not additionally broadened. At the same time, they are very intense, which allows deviations of the spectrum from the Gaussian spectrum in the line wings to be investigated. The line shape becomes an important indicator of bulk hydrodynamic processes because the cryogenic detectors of new generation of X-ray observatories will have a high energy resolution (from 5 eV for ASTRO-E2 to 1-2 eV for Constellation-X and XEUS). We use the spectral representation of a Kolmogorov cascade in the inertial range to calculate the characteristic shapes of X-ray lines. Sig...

  18. Dispersion-managed electrical transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Koon, K. Tse Ve [Institut Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Av. A. Savary, B.P. 47870, 21078 Dijon Cedex (France)], E-mail: kevin@u-bourgogne.fr; Dinda, P. Tchofo [Institut Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Av. A. Savary, B.P. 47870, 21078 Dijon Cedex (France)], E-mail: tchofo@u-bourgogne.fr; Marquie, P. [Laboratoire LEII, UMR CNRS No. 5158, Universite de Bourgogne, Aile de l' Ingenieur, B.P. 47870, 21078 Dijon Cedex (France)], E-mail: patrick.marquie@u-bourgogne.fr

    2009-05-30

    We examine the ability of electrical pulses to execute a highly stable propagation in a special electrical network made of concatenated pieces of discrete electrical lines with alternately positive and negative signs of the second-order dispersion. We show that such networks, called dispersion-managed electrical lines, induce a pulse breathing phenomenon, that is a dynamical behaviour with alternate regimes of pulse broadening and compression. This breathing phenomenon, which prevents the pulse from broadening without bounds during propagation in the network is the most appealing feature of the technique of dispersion management developed in the last decade in the area of optical communications. Meanwhile, we show that the benefit of using dispersion management in ETLs is strongly mitigated by the third-order dispersion and the losses at the junction points between adjacent pieces of line. These come into play as major factors of impairment for the pulse robustness with a much stronger impact than in dispersion-managed optical transmission lines.

  19. Dispersion-managed electrical transmission lines

    International Nuclear Information System (INIS)

    We examine the ability of electrical pulses to execute a highly stable propagation in a special electrical network made of concatenated pieces of discrete electrical lines with alternately positive and negative signs of the second-order dispersion. We show that such networks, called dispersion-managed electrical lines, induce a pulse breathing phenomenon, that is a dynamical behaviour with alternate regimes of pulse broadening and compression. This breathing phenomenon, which prevents the pulse from broadening without bounds during propagation in the network is the most appealing feature of the technique of dispersion management developed in the last decade in the area of optical communications. Meanwhile, we show that the benefit of using dispersion management in ETLs is strongly mitigated by the third-order dispersion and the losses at the junction points between adjacent pieces of line. These come into play as major factors of impairment for the pulse robustness with a much stronger impact than in dispersion-managed optical transmission lines.

  20. Water vapor line parameters from 6450 to 9400 cm−1

    International Nuclear Information System (INIS)

    The spectra of natural water vapor were recorded in the spectral range 6450–9400 cm−1 with a step-by-step Fourier transform spectrometer at room temperature with absorption path lengths up to 1200 m. Positions, intensities and self-broadening coefficients of about 11,000 lines were determined. This paper focuses on the intensity parameters: the lines of four isotopologues H216O, H218O, H217O and HD16O were observed and assigned; it presents a new experimental dataset in the 6450–9400 cm−1 spectral range. Obtained results were compared to the literature data. Fifty-nine new and corrected energy levels of H216O and H217O were determined from the vibration–rotation analysis of the observed lines. A brief discussion is added for self-broadening coefficients at the end of this paper. - Highlights: • New water vapor spectra recorded by FT Spectroscopy from 6450 to 9400 cm-1. • Retrieval of line parameters by multispectrum fitting procedure at room temperature. • Comparison of the line intensity measurements with data found in the literature. • Preliminary study of measured self-broadening coefficients

  1. Universal Representation of the H-like Spectral Line Shapes

    Science.gov (United States)

    Bureyeva, L.

    2009-05-01

    A universal approach for the calculation of Rydberg atom line shapes in plasmas is developed. It is based on analytical formulas for the intensity distribution in radiation transitions n→n' between highly excited atomic states with large values of principal quantum numbers n, n'≫1, with Δ n = n-n'≪n, and on the Frequency Fluctuation Model (FFM) to account of electron and ion thermal motion effects. The theory allows to describe a transition from the static to the impact broadening domains for every hydrogen spectral line. A new approach to extremely fast line shape calculations with account of charged particle dynamic effect was proposed. The approach is based on the close analogy between the static-impact broadening transition in the spectral line shape theory and the Doppler-Lorentz broadening in the Dicke narrowing effect theory. The precision of the new approach was tested by the comparison of hydrogen-alpha and beta line shapes calculations with the FFM results. The excellent agreement was discovered, the computer time decreased two orders of magnitudes as compared with the FFM.

  2. Pressure effects on water vapour lines: beyond the Voigt profile.

    Science.gov (United States)

    Ngo, N H; Tran, H; Gamache, R R; Hartmann, J M

    2012-06-13

    A short overview of recent results on the effects of pressure (collisions) regarding the shape of isolated infrared lines of water vapour is presented. The first part of this study considers the basic collisional quantities, which are the pressure-broadening and -shifting coefficients, central parameters of the Lorentzian (and Voigt) profile and thus of any sophisticated line-shape model. Through comparisons of measured values with semi-classical calculations, the influences of the molecular states (both rotational and vibrational) involved and of the temperature are analysed. This shows the relatively unusual behaviour of H(2)O broadening, with evidence of a significant vibrational dependence and the fact that the broadening coefficient (in cm(-1) atm(-1)) of some lines increases with temperature. In the second part of this study, line shapes beyond the Voigt model are considered, thus now taking 'velocity effects' into account. These include both the influence of collisionally induced velocity changes that lead to the so-called Dicke narrowing and the influence of the dependence of collisional parameters on the speed of the radiating molecule. Experimental evidence of deviations from the Voigt shape is presented and analysed. The interest of classical molecular dynamics simulations, to model velocity changes, together with semi-classical calculations of the speed-dependent collisional parameters for line-shape predictions from 'first principles', are discussed. PMID:22547229

  3. Broadening participation in Natural Sciences and Mathematics at the University of Maryland Baltimore County

    Science.gov (United States)

    Rous, Philip

    2013-03-01

    Over the past two decades, UMBC has undertaken a series of efforts to broaden participation in the natural sciences and mathematics, beginning with the establishment of the Meyerhoff program. Using as examples the multiple initiatives that followed, and with a focus on the challenge of increasing access and success of all students who enter as both freshmen and transfer students, I will describe a model of culture change that we have employed repeatedly to understand and guide our efforts in broadening participation. Particular attention will be paid to the concept of cultural capital, the role of innovators and the challenge of scaling small-scale innovations towards institutional change. Supported by the National Science Foundation and the Bill and Melinda Gates Foundation.

  4. In-medium jet evolution: interplay between broadening and decoherence effects

    CERN Document Server

    Apolinário, Liliana; Milhano, Guilherme; Salgado, Carlos A

    2015-01-01

    The description of the modifications of the coherence pattern in a parton shower, in the presence of a QGP, has been actively addressed in recent studies. Among the several achievements, finite energy corrections, transverse momentum broadening due to medium interactions and interference effects between successive emissions have been extensively improved as they seem to be essential features for a correct description of the results obtained in heavy-ion collisions. In this work, based on the insights of our previous work [1], we explore the physical interplay between broadening and decoherence, by generalising previous studies of medium-modifications of the antenna spectrum [2, 3, 4] - so far restricted to the case where transverse motion is neglected. The result allow us to identify two quantities controlling the decoherence of a medium modified shower that can be used as building blocks for a successful future generation of jet quenching Monte Carlo simulators: a generalisation of the $\\Delta_{med}$ paramet...

  5. Effect of nuclear motion on spectral broadening of high-order harmonic generation.

    Science.gov (United States)

    Yuan, Xiaolong; Wei, Pengfei; Liu, Candong; Ge, Xiaochun; Zheng, Yinghui; Zeng, Zhinan; Li, Ruxin

    2016-04-18

    High-order harmonic generation (HHG) in molecular targets is experimentally investigated in order to reveal the role of the nuclear motion played in the harmonic generation process. An obvious broadening in the harmonic spectrum from the H2 molecule is observed in comparison with the harmonic spectrum generated from other molecules with relatively heavy nuclei. We also find that the harmonic yield from the H2 molecule is much weaker than the yield from those gas targets with the similar ionization potentials, such as Ar atom and N2 molecule. The yield suppression and the spectrum broadening of HHG can be attributed to the vibrational motion of nuclear induced by the driving laser pulse. Moreover, the one-dimensional (1D) time-dependent Schrödinger equation (TDSE) with the non-Born-Oppenheimer (NBO) treatment is numerically solved to provide a theoretical support to our explanation. PMID:27137258

  6. Dielectric spectra broadening as the signature of dipole-matrix interaction. II. Water in ionic solutions.

    Science.gov (United States)

    Levy, Evgeniya; Puzenko, Alexander; Kaatze, Udo; Ben Ishai, Paul; Feldman, Yuri

    2012-03-21

    In this, the second part of our series on the dielectric spectrum symmetrical broadening of water, we consider ionic aqueous solutions. If in Part I, dipole-dipole interaction was the dominant feature, now ion-dipole interplay is shown to be the critical element in the dipole-matrix interaction. We present the results of high-frequency dielectric measurements of different concentrations of NaCl/KCl aqueous solutions. We observed Cole-Cole broadening of the main relaxation peak of the solvent in the both electrolytes. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the dynamics and structure of solutions of salts on one hand and dipolar solutes on the other hand. PMID:22443773

  7. From discrete to continuous the broadening of number concepts in early modern England

    CERN Document Server

    Neal, Katherine

    2002-01-01

    In the early modern period, a crucial transformation occurred in the classical conception of number and magnitude. Traditionally, numbers were merely collections of discrete units that measured some multiple. Magnitude, on the other hand, was usually described as being continuous, or being divisible into parts that are infinitely divisible. This traditional idea of discrete number versus continuous magnitude was challenged in the early modern period in several ways. This detailed study explores how the development of algebraic symbolism, logarithms, and the growing practical demands for an expanded number concept all contributed to a broadening of the number concept in early modern England. An interest in solving practical problems was not, in itself, enough to cause a generalisation of the number concept. It was the combined impact of novel practical applications together with the concomitant development of such mathematical advances as algebraic notation and logarithms that produced a broadened number conce...

  8. Spectral broadening effects of spontaneous emission and density of state on plasmonic enhancement in cermet waveguides.

    Science.gov (United States)

    Chen, Keyong; Feng, Xue; Zhang, Chao; Cui, Kaiyu; Huang, Yidong

    2013-01-14

    Based on the full integration formula of Purcell factor (PF) deduced from Fermi's Golden Rule, the plasmonic enhancement in Au(1-α)S3N4(α) cermet waveguides is evaluated with the joint impact of finite emission linewidth and the broadening of PF spectrum. The calculation results indicate that the PF would be significantly degraded by the two broadening effects though the SPP resonance frequency can be tuned with different volume fractions (α) of Si3N4. It is also found that the critical emission linewidth is approximately linear to the PF spectrum linewidth. Thus in order to achieve strong plasmonic enhancement, both the emission and PF spectrum linewidths should be dramatically reduced. PMID:23388935

  9. ABSORPTION PROPERTIES OF A DRIVEN FOUR-LEVEL DOPPLER-BROADENED SYSTEM

    Institute of Scientific and Technical Information of China (English)

    YUAN SHI; WU JIN-HUI; GAO JIN-YUE

    2001-01-01

    This paper deals with the absorption spectra of a weak probe in a four-level Doppler-broadened system driven by three coherent fields. The main aim is to extend earlier studies of the spontaneous emission spectrum and to present a comprehensive survey of the spectral features of this system. In addition to a derivation of exact formulae for the spectra, we give an explanation with the help of an appropriate set of dressed atomic states. We also get a deeper insight into the physical origin of gain in view of the existence of a population inversion between the levels of the lasing transition. Finally, we explore the effect of Doppler broadening on the absorption profile of the weak probe.

  10. Time sequence spectroscopy of AW UMa. The 518 nm Mg I triplet region analyzed with broadening functions

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, Slavek M., E-mail: rucinski@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street., Toronto, Ontario, M5S 3H4 (Canada)

    2015-02-01

    High-resolution spectroscopic observations of AW UMa, obtained on three consecutive nights with a median time resolution of 2.1 minutes, have been analyzed using the broadening function method in the spectral window of 22.75 nm around the 518 nm Mg i triplet region. Doppler images of the system reveal the presence of vigorous mass motions within the binary system; their presence puts into question the solid-body rotation assumption of the contact binary model. AW UMa appears to be a very tight, semi-detached binary; the mass transfer takes place from the more massive to the less massive component. The primary, a fast-rotating star with Vsini=181.4±2.5 km s{sup −1}, is covered with inhomogeneities: very slowly drifting spots and a dense network of ripples more closely participating in its rotation. The spectral lines of the primary show an additional broadening component (called the “pedestal”) that originates either in the equatorial regions, which rotate faster than the rest of the star by about 50 km s{sup −1}, or in an external disk-like structure. The secondary component appears to be smaller than predicted by the contact model. The radial velocity field around the secondary is dominated by accretion of matter transferred from (and possibly partly returned to) the primary component. The parameters of the binary are Asini=2.73±0.11 R{sub ⊙} and M{sub 1}sin{sup 3}i=1.29±0.15 M{sub ⊙}, M{sub 2}sin{sup 3}i=0.128±0.016 M{sub ⊙}. The mass ratio, q{sub sp}=M{sub 2}/M{sub 1}=0.099±0.003, while still the most uncertain among the spectroscopic elements, is substantially different from the previous numerous and mutually consistent photometric investigations which were based on the contact model. It should be studied why photometry and spectroscopy give such discrepant results and whether AW UMa is an unusual object or if only very high-quality spectroscopy can reveal the true nature of W UMa-type binaries.

  11. Angular Broadening of Intraday Variable AGN. II. Interstellar and Intergalactic Scattering

    OpenAIRE

    Lazio, T. J. W.; Ojha, R; Fey, A. L.; Kedziora-Chudczer, L.; Cordes, J.M.; Jauncey, D. L.; Lovell, J. E. J.

    2007-01-01

    We analyze a sample of 58 multi-wavelength, Very Long Baseline Array observations of active galactic nuclei (AGN) to determine their scattering properties. Approximately 75% of the sample consists of AGN that exhibit centimeter-wavelength intraday variability (interstellar scintillation) while the other 25% do not show intraday variability. We find that interstellar scattering is measurable for most of these AGN, and the typical broadening diameter is 2 mas at 1 GHz. We find that the scintill...

  12. Power broadening and Doppler effects of coherent dark resonances in Rb

    Science.gov (United States)

    Erhard, Michael; Nußmann, Stefan; Helm, Hanspeter

    2000-12-01

    Using a phase-locked laser pair we have observed dark resonances with linewidths below 30 Hz in a rubidium cell filled with neon as buffer gas. A model allowing for pressure broadening correctly reproduces the dependence of the width on the laser intensity. Consideration of velocity changing collisions reveals the absence of Doppler effects in the position and width of the dark resonance at high buffer-gas pressure.

  13. Pressure broadening of the ((dt. mu. )dee)/sup */ formation resonances

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, J.S.; Leon, M.; Padial, N.T.

    1988-01-01

    The treatment of ((dt..mu..)dee)/sup */ formation at high densities as a pressure broadening process is discussed. The quasistatic approximation is shown to satisfy the usual conditions of muon-catalyzed fusion better than does the impact approximation. Complete accurate results are shown for the impact approximation, and a preliminary rough treatment is presented to illustrate the quasistatic approximation. 13 refs., 8 figs.

  14. Broadening the scope of Open Innovation: Introduction to the special issue

    OpenAIRE

    Van de Vrande, Vraeska; Vanhaverbeke,Wim; Gassmann, Oliver

    2010-01-01

    In this first paper of the special issue, we identify some trends in open innovation research by analysing how the literature on this topics has evolved since the introduction of the concept in 2003. Research on open innovation has been mushrooming ever since and the scope has been broadened in different directions. Researchers also started to analyse open innovation at different level of analysis from the individual actors in organisations to ecosystems and national innovation systems. Despi...

  15. Broadening the scope of open innovation : past research, current state and future directions

    OpenAIRE

    Van de Vrande, Vareska; Vanhaverbeke,Wim; Gassmann, Oliver

    2010-01-01

    In this first paper of the special issue, we identify some trends in open innovation research by analysing how the literature on this topics has evolved since the introduction of the concept in 2003. Research on open innovation has been mushrooming ever since and the scope has been broadened in different directions. Researchers also started to analyse open innovation at different level of analysis from the individual actors in organisations to ecosystems and national innovation systems. Despi...

  16. Pressure broadening of the [(dtμ)dee]/sup */ formation resonances

    International Nuclear Information System (INIS)

    The treatment of [(dtμ)dee]/sup */ formation at high densities as a pressure broadening process is discussed. The quasistatic approximation is shown to satisfy the usual conditions of muon-catalyzed fusion better than does the impact approximation. Complete accurate results are shown for the impact approximation, and a preliminary rough treatment is presented to illustrate the quasistatic approximation. 13 refs., 8 figs

  17. Doppler broadening effect on collision cross section functions - Deconvolution of the thermal averaging

    Science.gov (United States)

    Bernstein, R. B.

    1973-01-01

    The surprising feature of the Doppler problem in threshold determination is the 'amplification effect' of the target's thermal energy spread. The small thermal energy spread of the target molecules results in a large dispersion in relative kinetic energy. The Doppler broadening effect in connection with thermal energy beam experiments is discussed, and a procedure is recommended for the deconvolution of molecular scattering cross-section functions whose dominant dependence upon relative velocity is approximately that of the standard low-energy form.

  18. The broadening spectrum of reputation risk in organizations: banking on risk and trust relationships

    OpenAIRE

    Scott, Susan V.; Walsham, Geoff

    2004-01-01

    Globalizing knowledge economies foster conditions that intensify the role and value of organizational reputation risk. In a holistic, enterprise focused era reputation is a key strategic construct that can act as a boundary object linking communities within and between organizations. Yet approaches to its management tend to be reactive and remain under the hold of industrial society principles. In this paper we examine the influences fuelling a broadening in the spectrum of organizational ...

  19. High Line

    OpenAIRE

    Jagielska, Anna

    2015-01-01

    This project examines The High Line in New York City and what is due to its success. The park, which runs through the meatpacking district in Manhattan, is on an old rail line that was abandoned from the 1980s. Two private locals, Joshua and Hammond, founded the non-profit organization “Friends of The High Line” and established the rail line into a public park. The aesthetics of the park is the wildness of the nature and the modern architecture in the middle of Manhattan mixed with a sustaina...

  20. Band broadening of DNA fragments isolated by polyacrylamide gel electrophoresis in capillary electrophoresis.

    Science.gov (United States)

    Kaneta, Takashi; Ogura, Takehito; Yamato, Shuhei; Imasaka, Totaro

    2012-02-01

    Polyacrylamide gel electrophoresis (PAGE) is used frequently for isolation and purification of DNA fragments. In the present study, DNA fragments extracted from polyacrylamide gels showed significant band broadening in capillary electrophoresis (CE). A pHY300PLK (a shuttle vector functioning in Escherichia coli and Bacillus subtilis) marker, which contained nine fragments ranging from 80 to 4870 bp, was separated by PAGE, and each fragment was isolated by phenol/chloroform extraction and ethanol precipitation. After extraction from the polyacrylamide gel, the peaks of the isolated DNA fragments exhibited band broadening in CE, where a linear poly(ethylene oxide) was used as a sieving matrix. The theoretical plate numbers of the DNA fragments contained in the pHY300PLK marker were >10(6) for all the fragments before extraction. However, the DNA fragments extracted from the polyacrylamide gel showed decreased theoretical plate numbers (5-20 times smaller). The degradation of the theoretical plate number was significant for middle sizes of the DNA fragments ranging from 489 to 1360 bp, whereas the largest and smallest fragments (80 and 4870 bp) had no obvious influence. The band broadening was attributed to contamination of the DNA fragments by polyacrylamide fibers during the separation and extraction process. PMID:22258810

  1. Overcoming Experimental and Intrinsic Broadening in Excited State Spectroscopies using Richardson-Lucy Deconvolution

    Science.gov (United States)

    Elam, W. T.; Fister, T. T.; Seidler, G. T.; Nagle, K. P.; Kas, J. J.; Cross, J. O.

    2007-03-01

    The oscillatory signature of the photoelectron interference phenomenon central to core shell spectroscopies is frequently broadened by experimental or intrinsic (i.e., core-hole lifetime) energy resolutions, limiting the interpretation of the measurement. For example, this problem occurs in x-ray absorption fine structure (XAFS) measurements of heavy elements where the core-hole lifetime is very short (/τcore-hole>=5,eV), and also in non-resonant x-ray Raman scattering measurements where the instrumental resolution (typically ˜1 eV) can be nearly an order of magnitude larger than the intrinsic energy resolution. Given the small statistical uncertainties in typical XAFS data and in recent XRS measurements using dedicated multielement spectrometers, the question naturally arises as to deconvolving the data with respect to the known instrumental or intrinsic resolutions. Here, we demonstrate that the Richardson-Lucy iterative algorithm provides a robust maximum likelihood method for addressing this issue in both XAFS and XRS. We demonstrate this method on core-hole broadened Ag XAFS data and experimentally broadened diamond and graphite XRS data.

  2. On the origin of the scatter broadening of fast radio burst pulses and astrophysical implications

    CERN Document Server

    Xu, Siyao

    2016-01-01

    Fast radio bursts (FRBs) have been identified as extragalactic sources which can make a probe of turbulence in the intergalactic medium (IGM) and their host galaxies. To account for the observed millisecond pulses caused by scatter broadening, we examine a variety of possible models of electron density fluctuations in both the IGM and the host galaxy medium. We find that a shallow power-law spectrum of density, which may arise in highly supersonic turbulence with pronounced local dense structures of shock-compressed gas in the host interstellar medium (ISM), can produce the required density enhancements at sufficiently small scales to interpret the scattering timescale of FRBs. It implies that an FRB residing in a galaxy with efficient star formation in action tends to have a broadened pulse. The scaling of the scattering time with dispersion measure (DM) in the host galaxy varies in different turbulence and scattering regimes. The host galaxy can be the major origin of scatter broadening, but contribute to a...

  3. Spectral broadening induced by intense ultra-short pulse in 4H–SiC crystals

    Science.gov (United States)

    Chun-hua, Xu; Teng-fei, Yan; Gang, Wang; Wen-jun, Wang; Jing-kui, Liang; Xiao-long, Chen

    2016-06-01

    We report the observation of spectral broadening induced by 200 femtosecond laser pulses with the repetition rate of 1 kHz at the wavelength of 532 nm in semi-insulating 4H–SiC single crystals. It is demonstrated that the full width at half maximum of output spectrum increases linearly with the light propagation length and the peak power density, reaching a maximum 870 cm‑1 on a crystal of 19 mm long under an incident laser with a peak power density of 60.1 GW/cm2. Such spectral broadening can be well explained by the self-phase modulation model which correlates time-dependent phase change of pulses to intensity-dependent refractive index. The nonlinear refractive index n 2 is estimated to be 1.88×10‑15 cm2/W. The intensity-dependent refractive index is probably due to both the nonlinear optical polarizability of the bound electrons and the increase of free electrons induced by the two-photon absorption process. Super continuum spectra could arise as crystals are long enough to induce the self-focusing effect. The results show that SiC crystals may find applications in spectral broadening of high power lasers. Project supported by the National High Technology Research and Development Program of China (Grant No. 2014AA041402) and the National Natural Science Foundation of China (Grant Nos. 51272276 and 51322211).

  4. Proton Lateral Broadening Distribution Comparisons Between GRNTRN, MCNPX, and Laboratory Beam Measurements

    Science.gov (United States)

    Mertens, Christopher J.; Moyers, Michael F.; Walker, Steven A.; Tweed, John

    2010-01-01

    Recent developments in NASA s deterministic High charge (Z) and Energy TRaNsport (HZETRN) code have included lateral broadening of primary ion beams due to small-angle multiple Coulomb scattering, and coupling of the ion-nuclear scattering interactions with energy loss and straggling. This new version of HZETRN is based on Green function methods, called GRNTRN, and is suitable for modeling transport with both space environment and laboratory boundary conditions. Multiple scattering processes are a necessary extension to GRNTRN in order to accurately model ion beam experiments, to simulate the physical and biological-effective radiation dose, and to develop new methods and strategies for light ion radiation therapy. In this paper we compare GRNTRN simulations of proton lateral broadening distributions with beam measurements taken at Loma Linda University Proton Therapy Facility. The simulated and measured lateral broadening distributions are compared for a 250 MeV proton beam on aluminum, polyethylene, polystyrene, bone substitute, iron, and lead target materials. The GRNTRN results are also compared to simulations from the Monte Carlo MCNPX code for the same projectile-target combinations described above.

  5. N2- and (H2+He)-broadened cross sections of benzene (C6H6) in the 7-15 μm region for the Titan and jovian atmospheres

    Science.gov (United States)

    Sung, Keeyoon; Toon, Geoffrey C.; Crawford, Timothy J.

    2016-06-01

    In support of atmospheric remote sensing of Titan and jovian planets, we measured absorption cross sections of benzene (C6H6) in the 7-15 μm region at temperatures between 235 K and 297 K. For this, high-resolution laboratory spectra of C6H6 were obtained using two cold cells (80 cm and 2.07 cm path length) configured to a high resolution Fourier-transform infrared (FT-IR) spectrometer, Bruker IFS-125HR, at the Jet Propulsion Laboratory (JPL). The spectrum sets include 15 pure and 15 N2-broadened benzene spectra in the 630-1534 cm-1 region, along with four additional spectra broadened by an H2(85%) and He(15%) gas mixture for the 630-740 cm-1 region. From these spectra, temperature dependent benzene cross sections were obtained for gas phase benzene in the presence of N2 and (H2+He) at ambient pressures and temperatures down to 235 K. In addition, we generated two independent sets of pseudolines: one of N2-broadened benzene for Titan and the other of (H2+He)-broadened benzene for jovian planets. It is shown that the benzene pseudolines can reproduce the observed features to ˜ 5% in transmittance, including the continuum-like absorption formed by numerous overlapping weak and hot band transitions. Based on the pseudoline parameters, the integrated band intensities at 296 K for the three strongest bands in the region were measured to be 177.0(73), 14.0(10), 27.2(9)×10-17 cm-1/(molecule·cm-2) in the region of v4 at 674 cm-1, v14 at 1038.267, and v13 at 1483.985 cm-1, respectively, from the combined set of pure and N2-broadened benzene spectra. For the (H2+He) mixture-broadened benzene spectra, the integrated band intensity for v4 band in the 630-735 cm-1 region was measured to be 168.8(17)×10-17 cm-1/(molecule·cm-2) at 296 K, which is in agreement with the intensity derived from the N2-broadened benzene spectra within the combined measurement uncertainties. The results from this work show an excellent agreement (2%) with one of the latest experimental studies by

  6. Measurements of NH3 linestrengths and collisional broadening coefficients in N2, O2, CO2, and H2O near 1103.46cm-1

    KAUST Repository

    Owen, Kyle

    2013-05-01

    Laser-based ammonia gas sensors have useful applications in many fields including combustion, atmospheric monitoring, and medical diagnostics. Calibration-free trace gas sensors require the spectroscopic parameters including linestrengths and collisional broadening coefficients to be known. Ammonia\\'s strong ν2 vibrational band between 9 - 12 μm has the high absorption strength needed for sensing small concentrations. Within this band, the 1103.46cm-1 feature is one of the strongest and has minimal interference from CO2 and H2O. However, the six rotational transitions that make up this feature have not been studied previously with absorption spectroscopy due to their small line spacing ranging from 0.004 to 0.029cm-1. A tunable quantum cascade laser was used to accurately study these six transitions. A retrieval program was used to determine the linestrengths and collisional broadening coefficients based on Voigt and Galatry profiles. The experiments were performed with ammonia mixtures in nitrogen, oxygen, water vapor, and carbon dioxide at room temperature in an optical cell. These data are going to aid in the development of quantitative ammonia sensors utilizing this strong absorption feature. © 2013 Elsevier Ltd.

  7. The IACOB project: IV. New predictions for high-degree non-radial mode instability domains in massive stars and connection with macroturbulent broadening

    CERN Document Server

    Godart, M; Herrero, A; Dupret, M A; Grötsch-Noels, A; Salmon, S J A J; Ventura, P

    2016-01-01

    Asteroseismology is a powerful tool to access the internal structure of stars. Apart from the important impact of theoretical developments, progress in this field has been commonly associated with the analysis of time-resolved observations. Recently, the so-called macroturbulent broadening has been proposed to be a complementary and less expensive way -- in terms of observational time -- to investigate pulsations in massive stars. We assess to what extent this ubiquitous non-rotational broadening component shaping the line profiles of O stars and B supergiants is a spectroscopic signature of pulsation modes driven by a heat mechanism. We compute stellar main sequence and post-main sequence models from 3 to 70Msun with the ATON stellar evolution code and determine the instability domains for heat-driven modes for degrees l=1-20 using the adiabatic and non-adiabatic codes LOSC and MAD. We use the observational material presented in Sim\\'on-D\\'iaz et al. (2016) to investigate possible correlations between the si...

  8. Blurring lines

    OpenAIRE

    Howard, Heidi C; Knoppers, Bartha Maria; Borry, Pascal

    2010-01-01

    Companies that offer direct-to-consumer genetic testing and conduct research are blurring the line between customers and research subjects. Should these companies adhere to the same ethical regulations as academic researchers?

  9. High Line

    DEFF Research Database (Denmark)

    Kiib, Hans

    2015-01-01

    . The High Line project has been carried out as part of an open conversion strategy. The result is a remarkable urban architectural project, which works as a catalyst for the urban development of Western Manhattan. The greater project includes the restoration and reuse of many old industrial buildings......At just over 10 meters above street level, the High Line extends three kilometers through three districts of Southwestern Manhattan in New York. It consists of simple steel construction, and previously served as an elevated rail line connection between Penn Station on 34th Street and the many...... in close proximity to the park bridge and new projects being added to fit the context. The outcome is a conglomeration of non-contemporary urban activities along the High Line, where mechanical workshops, small wholesale stores. etc. mix with new exclusive residential buildings, eminent cafés, and...

  10. Collisional shifts and broadenings of the 4sns {sup 1}S{sub 0} and 4snd {sup 1}D{sub 2} Rydberg series of calcium perturbed by inert gases

    Energy Technology Data Exchange (ETDEWEB)

    Marafi, M; Afrousheh, K; Makdisi, Y; Suji, Z; Mathew, J [Department of Physics, Kuwait University, PO Box 5969, 13060 Safat (Kuwait)], E-mail: marafim@kuc01.kuniv.edu.kw

    2009-07-28

    An excimer pumped dye laser was used to measure collisional shift and broadening rates of the nd {sup 1}D{sub 2} (n = 4-50) and ns {sup 1}S{sub 0} series (n = 5-30) of calcium Rydberg states. Two-photon absorption techniques were used to populate the Rydberg states. High-resolution Ca excitation spectra were measured using a diode detector while scanning the frequency of the dye laser. Inert gases Ar, Kr and Xe were used as perturbers at pressures of 100 mbar. Shifts and broadenings of spectral lines were measured as functions of the principal quantum number n. The pressure-dependence behaviour of the 4s63d {sup 1}D{sub 2} Rydberg state as well as its configuration interactions is discussed.

  11. Phenomenological model for spectral broadening of incoherent light in fibers via self-phase modulation and dispersion

    CERN Document Server

    Li, Qinghua; Shen, Xinglai; Hao, He; Gong, Mali

    2016-01-01

    A phenomenological model for spectral broadening of incoherent light in silica fibers via self-phase modulation and dispersion is presented, aiming at providing a qualitative and readily accessible description of incoherent light spectral broadening. In this model, the incoherent light is approximated by a cosine power-modulated light with modulation parameters depending on the coherent time and the dispersion in fibers. A simple and practical method for spectral broadening predictions is given and demonstrated by both the straightforward NLSE-based numerical modeling and series of experiments including narrowband and broadband incoherent light in passive fibers and fiber amplifiers.

  12. Seyfert 2 galaxies with unusually wide nebular lines

    CERN Document Server

    Winkler, Hartmut

    2014-01-01

    We report on a set of AGN that match the Seyfert 2 galaxy classification criteria, but display unusually wide "narrow" lines, with the 4959 {\\AA} and 5007 {\\AA} nebular lines overlapping with each other. This spectral line broadening is in most cases evidence of a complex profile with multiple components. It indicates an unusual narrow line region with diverse gas clouds and a range of velocity systems. We list 14 such objects with these characteristics identified in a set of Sloan Digital Sky Survey spectra. We measure the strengths of all lines visible in the spectrum, and attempt to fit multiple Gaussian profiles to the nebular lines. We quantify the line parameters of all multiple velocity systems discovered. We compare the spectral characteristics of our sample with those of other, 'conventional' type 2 Seyferts and attempt to determine whether other systematic spectral differences exist. We consider whether the investigated sample constitutes a clear sub-class of the Seyfert 2 population. In conclusion ...

  13. PUMPING UP THE [N I] NEBULAR LINES

    International Nuclear Information System (INIS)

    The optical [N I] doublet near 5200 Å is anomalously strong in a variety of emission-line objects. We compute a detailed photoionization model and use it to show that pumping by far-ultraviolet (FUV) stellar radiation previously posited as a general explanation applies to the Orion Nebula (M42) and its companion M43; but, it is unlikely to explain planetary nebulae and supernova remnants. Our models establish that the observed nearly constant equivalent width of [N I] with respect to the dust-scattered stellar continuum depends primarily on three factors: the FUV to visual-band flux ratio of the stellar population, the optical properties of the dust, and the line broadening where the pumping occurs. In contrast, the intensity ratio [N I]/Hβ depends primarily on the FUV to extreme-ultraviolet ratio, which varies strongly with the spectral type of the exciting star. This is consistent with the observed difference of a factor of five between M42 and M43, which are excited by an O7 and B0.5 star, respectively. We derive a non-thermal broadening of order 5 km s–1 for the [N I] pumping zone and show that the broadening mechanism must be different from the large-scale turbulent motions that have been suggested to explain the line widths in this H II region. A mechanism is required that operates at scales of a few astronomical units, which may be driven by thermal instabilities of neutral gas in the range 1000-3000 K. In an Appendix A, we describe how collisional and radiative processes are treated in the detailed model N I atom now included in the CLOUDY plasma code.

  14. Measurement of atomic Stark parameters of many Mn I and Fe I spectral lines using GMAW process

    International Nuclear Information System (INIS)

    The particular character of the welding arc working in pure argon, whose emission spectrum consists of many spectral lines strongly broadened by the Stark effect, has allowed measurement, sometimes for the first time, of the Stark parameters of 15 Mn I and 10 Fe I atomic spectral lines, and determination of the dependence on temperature of normalized Stark broadening in Ne = 1023 m-3 of the 542.4 nm atomic iron line. These results show that special properties of the MIG plasma may be useful in this domain because composition of the wire-electrode may be easily adapted to the needs of an experiment.

  15. Measurement of atomic Stark parameters of many Mn I and Fe I spectral lines using GMAW process

    Energy Technology Data Exchange (ETDEWEB)

    Zielinska, S; Pellerin, S; Valensi, F [GREMI, Universite d' Orleans (Site de Bourges)/CNRS, BP 4043, 18028 Bourges cedex (France); Dzierzega, K; Musiol, K [Marian Smoluchowski Institute of Physics, Jagellonian University, Krakow (Poland); Briand, F, E-mail: sylwia.zielinska@airliquide.co, E-mail: stephane.pellerin@univ-orleans.f, E-mail: krzycho@netmail.if.uj.edu.p, E-mail: flavien.valensi@laplace.univ-tsle.f, E-mail: ufmusiol@cyf-kr.edu.p, E-mail: francis.briand@airliquide.co [CTAS-Air Liquide Welding, Saint Ouen l' Aunone, 95315 Cergy-Pontoise cedex (France)

    2010-11-03

    The particular character of the welding arc working in pure argon, whose emission spectrum consists of many spectral lines strongly broadened by the Stark effect, has allowed measurement, sometimes for the first time, of the Stark parameters of 15 Mn I and 10 Fe I atomic spectral lines, and determination of the dependence on temperature of normalized Stark broadening in N{sub e} = 10{sup 23} m{sup -3} of the 542.4 nm atomic iron line. These results show that special properties of the MIG plasma may be useful in this domain because composition of the wire-electrode may be easily adapted to the needs of an experiment.

  16. Iron line variability of discoseismic corrugation modes

    Science.gov (United States)

    Tsang, David; Butsky, Iryna

    2013-10-01

    Using a fast semi-analytic raytracing code, we study the variability of relativistically broadened Fe-Kα lines due to discoseismic oscillations concentrated in the innermost regions of accretion discs around black holes. The corrugation mode, or c-mode, is of particular interest as its natural frequency corresponds well to the ˜0.1-15 Hz range observed for low-frequency quasi-periodic oscillations (LFQPOs) for lower spins. Comparison of the oscillation phase dependent variability and quasi-periodic oscillation-phase stacked Fe-Kα line observations will allow such discoseismic models to be confirmed or ruled out as a source of particular LFQPOs. The spectral range and frequency of the variability of the Fe-Kα line due to c-modes can also potentially be used to constrain the black hole spin if observed with sufficient temporal and spectral resolution.

  17. Iron Line Variability of Discoseismic Corrugation Modes

    CERN Document Server

    Tsang, David

    2013-01-01

    Using a fast semi-analytic raytracing code, we study the variability of relativistically broadened iron lines due to discoseismic oscillations concentrated in the inner-most regions of accretion discs around black holes. The corrugation mode, or c-mode, is of particular interest as its natural frequency corresponds well to the ~0.1-15Hz range observed for low-frequency quasi-periodic oscillations (LFQPOs) for lower spins. Comparison of the oscillation phase dependent variability and QPO-phase stacked iron line observations will allow such discoseismic models to be confirmed or ruled out as a source of particular LFQPOs. The spectral range and frequency of the variability of the iron line due to corrugation modes can also potentially be used to constrain the black hole spin if observed with sufficient temporal and spectral resolution.

  18. Study of Doppler broadening of positrons annihilation radiation in (Smsub(0.8)Gdsub(0.2))S across valence transition

    International Nuclear Information System (INIS)

    Doppler broadening of positron annihilation radiation was measured as a function of temperature in (Smsub(0.8)Gdsub(0.2))S. A hyperpure Ge spectrometer system having a resolution, FWHM = 0.97 keV for the 514 keV gamma ray of 85Sr has been used for the measurements. The assembly of the 22Na source and sample was mounted on the cold-finger of a variable temperature cryostat. Measurements were made at various temperatures from 71 K to 300 K. The spectra were analyzed to extract a line-shape parameter S, which is defined as the ratio of the total counts under a small segment of the photo-peak to the sum of counts under a segment on either wing of the spectrum. (author)

  19. Detection of Voigt Spectral Line Profiles of Hydrogen Radio Recombination Lines toward Sagittarius B2(N)

    CERN Document Server

    von Prochazka, Azrael A; Balser, Dana S; Ryans, Robert S I; Marshall, Adele H; Schwab, Fredric R; Hollis, Jan M; Jewell, Philip R; Lovas, Frank J

    2010-01-01

    We report the detection of Voigt spectral line profiles of radio recombination lines (RRLs) toward Sagittarius B2(N) with the 100-m Green Bank Telescope (GBT). At radio wavelengths, astronomical spectra are highly populated with RRLs, which serve as ideal probes of the physical conditions in molecular cloud complexes. An analysis of the Hn(alpha) lines presented herein shows that RRLs of higher principal quantum number (n>90) are generally divergent from their expected Gaussian profiles and, moreover, are well described by their respective Voigt profiles. This is in agreement with the theory that spectral lines experience pressure broadening as a result of electron collisions at lower radio frequencies. Given the inherent technical difficulties regarding the detection and profiling of true RRL wing spans and shapes, it is crucial that the observing instrumentation produce flat baselines as well as high sensitivity, high resolution data. The GBT has demonstrated its capabilities regarding all of these aspects,...

  20. Voigt-function modeling in Fourier analysis of size- and strain-broadened X-ray diffraction peaks

    Energy Technology Data Exchange (ETDEWEB)

    Balzar, D.; Ledbetter, H. (Materials Science and Engineering Lab., National Inst. of Standards and Technology, Boulder, CO (United States))

    1993-02-01

    With the assumption that both size- and strain-broadened profiles of the pure-specimen function are described with a Voigt function, it is shown that the analysis of Fourier coefficients leads to the Warren-Averbach method of separation of size and strain contributions. The analysis of size coefficients shows that the 'hook' effect occurs when the Cauchy content of the size-broadened profile is underestimated. The ratio of volume-weighted and surface-weighted domain sizes can change from [proportional to]1.31, for the minimum allowed Cauchy content, to 2, when the size-broadened profile is given solely by a Cauchy function. If the distortion coefficient is approximated by a harmonic term, mean-square strains decrease linearly with increasing the averaging distance. The local strain is finite only in the case of purely Gaussian strain broadening, because strains are then independent of averaging distance. (orig.).

  1. 77 FR 2031 - Proposed Information Collection; Comment Request; Market Research To Broaden and Deepen U.S...

    Science.gov (United States)

    2012-01-13

    ... International Trade Administration Proposed Information Collection; Comment Request; Market Research To Broaden...) have formed a project team to conduct market segmentation research and analysis. The market... return of investment. The purpose of this initiative is to gain market knowledge and...

  2. Determination of spectral parameters for lines targeted by the Tunable Laser Spectrometer (TLS) on the Mars Curiosity rover

    Science.gov (United States)

    Manne, Jagadeeshwari; Webster, Christopher R.

    2016-03-01

    Molecular line parameters of line strengths, self- and foreign-broadening by nitrogen, carbon dioxide and helium gas have been experimentally determined for infrared ro-vibrational spectral lines of water and carbon dioxide at 2.78 μm targeted by the Tunable Laser Spectrometer (TLS) in the Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity rover. Good agreement is found by comparison with the line parameters reported in the HITRAN-2012 database.

  3. First measurements of nitrous oxide self-broadening and self-shift coefficients in the 0002-0000 band at 2.26 μm using high resolution Fourier transform spectroscopy

    Science.gov (United States)

    Werwein, Viktor; Brunzendorf, Jens; Serdyukov, Anton; Werhahn, Olav; Ebert, Volker

    2016-05-01

    Nitrous oxide (N2O) is one of the most important greenhouse gases in the terrestrial atmosphere and is routinely measured with ground-based FTIR networks like the Total Carbon Column Observing Network (TCCON). A spectral window for the TCCON retrievals is the 14N216O 0002-0000-band region from 4375 to 4445 cm-1 (2.250-2.285 μm). In our study, we present the first high-resolution Fourier transform spectrometer measurements of self-broadening and self-shift coefficients in the range of 53-1019 hPa for the lines R0e-R40e of this band. The line parameters were determined at 296 K using metrologically validated temperature, and pressure values, which were traced back to the SI-units. The averaged estimated relative uncertainties for the coverage factor of k = 2 (two times the standard deviation) are 0.3% and 9.5% with a standard deviation of 0.1% and 5.3% for the self-broadening and the self-shift coefficients, respectively. Vacuum line positions, determined for the first time by taking the self-shift coefficients into account are also reported with an estimated averaged relative uncertainty of 1.1 ∗ 10-8 for k = 2 and a standard deviation of 3 ∗ 10-9. A well-defined uncertainty assessment for the measured line parameters is given.

  4. Elastic LO-phonon scattering as an efficient mechanism of dephasing and homogeneous broadening in quantum dots

    DEFF Research Database (Denmark)

    Uskov, Alexander V.; Tromborg, Bjarne; Jauho, Antti-Pekka;

    2000-01-01

    The spectral linewidth of optical transitions in quantum dots is shown to be strongly broadened by elastic scattering of LO phonons on the confined carriers. The scattering does not excite the carriers but results in a large dephasing rate.......The spectral linewidth of optical transitions in quantum dots is shown to be strongly broadened by elastic scattering of LO phonons on the confined carriers. The scattering does not excite the carriers but results in a large dephasing rate....

  5. Spectral broadening and temporal compression of 100 fs pulses in air-filled hollow core capillary fibers,

    OpenAIRE

    C. Li; Rishad, K.P.M.; Horak, P.; Matsuura, Y.; Faccio, D

    2014-01-01

    We experimentally study the spectral broadening of intense, ~100 femtosecond laser pulses at 785 nm coupled into different kinds of hollow core capillary fibers, all filled with air at ambient pressure. Differently from observations in other gases, the spectra are broadened with a strong red-shift due to highly efficient intrapulse Raman scattering. Numerical simulations show that such spectra can be explained only by increasing the Raman fraction of the third order nonlinearity close to 100%...

  6. Broadening engineering education: bringing the community in : commentary on "social responsibility in French engineering education: a historical and sociological analysis".

    Science.gov (United States)

    Conlon, Eddie

    2013-12-01

    Two issues of particular interest in the Irish context are (1) the motivation for broadening engineering education to include the humanities, and an emphasis on social responsibility and (2) the process by which broadening can take place. Greater community engagement, arising from a socially-driven model of engineering education, is necessary if engineering practice is to move beyond its present captivity by corporate interests. PMID:24072611

  7. Laboratory measurement of H2O2 pressure broadening parameter for JEM/SMILES Observation from International Space Station

    Science.gov (United States)

    Sato, T.; Mizoguchi, A.; Kasai, Y.; Kanamori, H.

    2009-12-01

    A new generation of sub-millimeter-wave receivers employing sensitive SIS (Superconductor Insulator Superconductor) detector technology will provide new opportunities for precise remote sensing measurements of minor constituents in the earth and planetary atmosphere.Superconducting Sub-Millimeter-Wave Limb-Emission Sounder (SMILES) was designed to be onboard the Japanese Experiment Module (JEM) on the International Space Station (ISS) as a collaboration project of National Institute of Information and Communications Technology (NICT) and Japan Aerospace Exploration Agency (JAXA).SMILES in Transfer Vehicle (HTV) plan to launch in September 11 2009 by Japanese H-IIB rocket. JEM/SMILES will allow to observe the atmospheric species such as O3, H35Cl, H37Cl, ClO, BrO, HOCl, HO2, H2O2, HNO3 and CH3CN, Ozone isotope species, and water vapor with the precisions in a few to several tens percents [1] in the altitude region upper troposphere (about 8km in mid-latitude) and the mesosphere (about 90km in mid-latitude). In this paper, laboratory measurement of the pressure broadening parameter (γ) of Hydrogen peroxide (H2O2) at JKa,Kc = 201,19 - 192,17 rotational transition (625.044 GHz) will be presented. This is one of the target transitions of JEM/SMILES observation. γ of H2O2 in sub-millimeter-wave region was measured for the first time. The measurement was carried out using a sub-millimeter-wave absorption spectrometric system in Tokyo Institute of Technology.The radiation source from a backward wave oscillator (BWO) was phase-locked to the harmonics of a synthesized sweeper with two-step phase lock loop. The BWO source frequency was modulated with the modulation frequency of 51 kHz. H2O2 sample was prerpared by distillation of commercial available 30% solution. The pressures of sample and buffer gas (N2 and O2) were controlled by a mass flow meter and monitored by two Baratron monitors in the cell. From the observed profiles of the spectrum, the pressure broadening line

  8. Measurement of pressure-broadening parameters for the CO-He system at 4 K

    International Nuclear Information System (INIS)

    A technique has been developed to observe collisions in a regime where the rotational energy-level separation is greater than the thermal energy. Pressure-broadening parameters of trace quantities of CO, thermalized by collisions with helium at 4 K, were measured and found to be 10.1 and 11.2 MHz/Torr half width at half maximum for the J = 0-1 and J = 1-2 transitions, respectively. At 4 K only a small number of collision channels are energetically available and comparisons between experiment and theory are facilitated

  9. A revised uncertainty budget for measuring the Boltzmann constant using the Doppler Broadening Technique on ammonia

    CERN Document Server

    Lemarchand, Cyril; Sow, Papa Lat Tabara; Triki, Meriam; Tokunaga, Sean K; Briaudeau, Stephan; Chardonnet, Christian; Darquié, Benoît; Daussy, Christophe

    2013-01-01

    We report on our on-going effort to measure the Boltzmann constant, kB, using the Doppler Broadening Technique. The main systematic effects affecting the measurement are discussed. A revised error budget is presented in which the global uncertainty on systematic effects is reduced to 2.3 ppm. This corresponds to a reduction of more than one order of magnitude compared to our previous Boltzmann constant measurement. Means to reach a determination of kB at the part per million accuracy level are outlined.

  10. The variable temperature pressure broadening and pressure shift of CO in collision with helium

    International Nuclear Information System (INIS)

    Pressure broadening and pressure shift parameters have been measured for CO in collision with helium over a wide range of temperatures. This temperature range includes the high temperature semiclassical regime in which the physics of the collision is properly described by Anderson-like theories as well as the low temperature regime in which new phenomena associated with quasibound states require a more complete quantum mechanical description. Experimental results will be compared to theoretical predictions generated from a variety of CO-He potential energy surfaces. The discrepancy between experiment and the best available potential energy surface will be discussed

  11. The Need for a National Alliance for Broadening Participation of Native Americans in the Geosciences.

    Science.gov (United States)

    Dalbotten, D. M.

    2008-12-01

    The continuing underrepresentation of Native Americans in the Geosciences can only mean that Native voices go unheard in setting research agendas and priorities. This is particularly significant where issues such as global climate change impact the land and livelihood of Native American communities. This talk will outline the need for a national alliance for broadening participation of Native Americans in the Geosciences. Our focus will be on defining goals for this alliance, i.e., new research in Geoscience education, defining best practices, inclusion of Native voices in Geoscience research, the potential for new collaborations, and promotion of opportunities for Native students and communities.

  12. [Determination of electron density in atmospheric pressure radio frequency dielectric barrier discharges by Stark broadening].

    Science.gov (United States)

    Li, Sen; Liu, Zhong-wei; Chen, Qiang; Liu, Fu-ping; Wang, Zheng-duo; Yang, Li-zhen

    2012-01-01

    The use of high frequency power to generate plasma at atmospheric pressure is a relatively new development. An apparatus of atmospheric pressure radio frequency dielectric barrier discharge was constructed. Plasma emission based measurement of electron density in discharge columns from Stark broadening Ar is discribed. The spacial profile of electron density was studied. In the middle of the discharge column, as the input power increases from 138 to 248 W, the electron density rises from 4.038 x 10(21) m(-3) to 4.75 x 10(21) m(-3). PMID:22497121

  13. Broadening of axial neutron flux difference operating band in Angra I

    International Nuclear Information System (INIS)

    ANGRA I Technical Specifications requires the axial flux difference to remain within ± 5 percent band, relative to a reference value, for any power level. The reference value is the axial flux difference at a 100% power, all rods (almost) out and equilibrium Xenon distribution. This paper presents the results of several Simulations, performed by FURNAS staff aiming the validation of calculation results against the reload designer's ones. It was also proved that the Axial Flux Difference Operating band can be broadened to ''Ref. +- 6.9% ) without exce eding the limit imposed by the ''envelope-curve''. (author)

  14. Photon-echo quantum memories in inhomogeneously broadened two-level atoms

    International Nuclear Information System (INIS)

    Here, we propose a solid-state quantum memory that does not require spectral holeburning, instead using strong rephasing pulses like traditional photon-echo techniques. The memory uses external broadening fields to reduce the optical depth and so switch off the collective atom-light interaction when desired. The proposed memory should allow operation with reasonable efficiency in a much broader range of material systems, for instance Er3+ doped crystals which have a transition at 1.5 μm. We present analytic theory supported by numerical calculations and initial experiments.

  15. Gauge invariant formulation of the intracollisional field effect including collisional broadening

    International Nuclear Information System (INIS)

    A gauge-invariant formalism is presented for describing nonperturbatively the effects of the electric field on electron-phonon scattering in a nondegenerate semiconductor. The Kadanoff-Bayn nonequilibrium formulation of many-body systems is employed to treat the intracollisional field effect and collisional broadening on equal footing. We derive an analytic, gauge-invariant model for the spectral density function and for the density of energy states which accounts for both effects simultaneously in a relatively simple and rigorous way. (orig.)

  16. Broadening the Service Offering for Customers of University Properties of Finland

    OpenAIRE

    Rinne, Anita

    2013-01-01

    The background of this thesis is the commissioner’s, University Properties of Finland Ltd, who aim to find out the service needs of the University campus users. The company is developing and letting the campuses for Universities and their customers to use. It has a vision to make campuses lively UniverCities. This goal demands new services and service providers to come to the campuses. The aim of this thesis is to find out if there are possibilities to broaden the service offering in Uni...

  17. A technique to study the mechanisms of pressure broadening of spectral holes

    International Nuclear Information System (INIS)

    An experimental procedure to distinguish between the two possible mechanisms (dispersive and diffusive) of pressure broadening of spectral holes in nonisobaric experiments is proposed. The method makes use of nonlinear saturation properties of the hole burning process. The proposed four-step procedure consists of burning a hole, applying hydrostatic pressure to the system, additional burning at the hole minimum at this second pressure, and then applying more pressure. By model calculations it is demonstrated that, under certain conditions, the dispersive mechanism yields a double-minimum hole, while the diffusive mechanism does not. Experimental observability of such an effect is discussed. (author)

  18. Convergence of Legendre Expansion of Doppler-Broadened Double Differential Elastic Scattering Cross Section

    International Nuclear Information System (INIS)

    Convergence properties of Legendre expansion of a Doppler-broadened double-differential elastic neutron scattering cross section of 238U near the 6.67 eV resonance at temperature 103 K are studied. A variance of Legendre expansion from a reference Monte Carlo computation is used as a measure of convergence and is computed for as many as 15 terms in the Legendre expansion. When the outgoing energy equals the incoming energy, it is found that the Legendre expansion converges very slowly. Therefore, a supplementary method of computing many higher-order terms is suggested and employed for this special case.

  19. Correlation effects in the theory of combined Doppler and pressure broadening. I - Classical theory

    Science.gov (United States)

    Ward, J.; Cooper, J.; Smith, E. W.

    1974-01-01

    An investigation is conducted of the combined effects of radiator-perturber collisions and radiator translational motion in the context of foreign gas broadening of optical transitions in neutral radiators. Questions concerning the speed-dependent collision frequency are considered and aspects of general theory are explored, taking into account the correlation function, the ensemble average, and the kinetic equation formalism. An elementary solution is discussed along with a one-perturber approximation, inverse power law model calculations, and a comparison with the Voigt profile.

  20. Macroscopic effects in electromagnetically-induced transparency in a Doppler-broadened system

    International Nuclear Information System (INIS)

    We study the electromagnetically-induced transparency (EIT) in a Doppler-broadened cascaded three-level system. We decompose the susceptibility responsible for the EIT resonance into a linear and a nonlinear part, and the EIT resonance reflects mainly the characteristics of the nonlinear susceptibility. It is found that the macroscopic polarization interference effect plays a crucial role in determining the EIT resonance spectrum. To obtain a Doppler-free spectrum there must be polarization interference between atoms of different velocities. A dressed-state model, which analyzes the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting, is employed to explain the results. (paper)

  1. Vacancy type defect formation in irradiated α-iron investigated by positron beam Doppler broadening technique

    International Nuclear Information System (INIS)

    Vacancy type defects formations have been investigated in virgin and irradiated a-iron samples using slow positron beam Doppler broadening technique. Mono-vacancies and vacancy clusters are observed in 1.5 MeV 4He ions irradiated Fe samples at varying fluences from 1×1013 to 1×1017 cm−2. In the 1.2 MeV Yttrium ions implantation at low fluence 1×1014 cm−2 vacancy clusters with higher concentration and larger size are formed. In this sample, vacancy defects are detected deeper than predicted by SRIM calculation due to channelling.

  2. CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf

    Science.gov (United States)

    Wende, S.; Reiners, A.; Seifahrt, A.; Bernath, P. F.

    2010-11-01

    Molecular FeH provides a large number of sharp and isolated absorption lines that can be used to measure radial velocity, rotation, or magnetic field strength with high accuracy. Our aim is to provide an FeH atlas for M-type stars in the spectral region from 986 nm to 1077 nm (Wing-Ford band). To identify these lines in CRIRES spectra of the magnetically inactive, slowly rotating, M5.5 dwarf GJ1002, we calculated model spectra for the selected spectral region with theoretical FeH line data. In general this line list agrees with the observed data, but several individual lines differ significantly in position or in line strength. After identification of as many as possible FeH lines, we corrected the line data for position and line strength to provide an accurate atlas of FeH absorption lines for use in high precision spectroscopy of low mass stars. For all lines, we used a Voigt function to obtain their positions and equivalent widths. Identification with theoretical lines was done by hand. For confirmation of the identified lines, we used statistical methods, cross-correlation techniques, and line intensities. Eventually, we were able to identify FeH lines from the (0,0), (1,0), (1,1), (2,1), (2,2), (3,2), and (4,3) vibrational bands in the observed spectra and correct the positions of the lines if necessary. The deviations between theoretical and observed positions follow a normal distribution approximately around zero. In order to empirically correct the line strength, we determined Teff, instrumental broadening (rotational broadening) and a van der Waals enhancement factor for the FeH lines in GJ1002. We also give the scaling factors for the Einstein A values to correct the line strengths. With the identified lines, we derived rotational temperatures from the line intensities for GJ1002. We conclude that FeH lines can be used for a wide variety of applications in astrophysics. With the identified lines it will be possible for example to characterize magnetically

  3. Influence of the multiple scattering of relativistic electrons on the line width of backward Parametric X-ray Radiation in the absence of photo absorption

    CERN Document Server

    Tabrizi, Mehdi

    2015-01-01

    The multiple scattering effect on the line width of backward Parametric X-ray Radiation (PXR) in the extremely Bragg geometry, produced by low energy relativistic electrons traversing a single crystal, is discussed. It is shown that there exist conditions, when the influence of photo absorption on the line width can be neglected, and the only multiple scattering process of relativistic electrons in crystal leads to the broadening of backward PXR lines. Based on the obtained theoretical results, the line width broadening of backward PXR, caused by the multiple scattering of 30 MeV and 50 MeV relativistic electrons in a Si crystal of varying thicknesses, is numerically obtained.

  4. The effects of numerical resolution on hydrodynamical surface convection simulations and spectral line formation

    CERN Document Server

    Asplund, M; Nordlund, A A; Stein, R F; Nordlund, AA.

    2000-01-01

    The computationally demanding nature of radiative-hydrodynamical simulations of stellar surface convection warrants an investigation of the sensitivity of the convective structure and spectral synthesis to the numerical resolution and dimension of the simulations, which is presented here. With too coarse a resolution the predicted spectral lines tend to be too narrow, reflecting insufficient Doppler broadening from the convective motions, while at the currently highest affordable resolution the line shapes have converged essentially perfectly to the observed profiles. Similar conclusions are drawn from the line asymmetries and shifts. In terms of abundances, weak FeI and FeII lines show a very small dependence (~0.02 dex) while for intermediate strong lines with significant non-thermal broadening the sensitivity increases (~0.10 dex). Problems arise when using 2D convection simulations to describe an inherent 3D phenomenon, which translates to inaccurate atmospheric velocity fields and temperature and pressur...

  5. Broadening Participation of Women and Underrepresented Minorities in STEM through a Hybrid Online Transfer Program.

    Science.gov (United States)

    Drew, Jennifer C; Galindo-Gonzalez, Sebastian; Ardissone, Alexandria N; Triplett, Eric W

    2016-01-01

    The Microbiology and Cell Science (MCS) Department at the University of Florida (UF) developed a new model of a 2 + 2 program that uses a hybrid online approach to bring its science, technology, engineering, and mathematics (STEM) curriculum to students. In this paradigm, 2-year graduates transfer as online students into the Distance Education in MCS (DE MCS) bachelor of science program. The program has broadened access to STEM with a steadily increasing enrollment that does not draw students away from existing on-campus programs. Notably, half of the DE MCS students are from underrepresented minority (URM) backgrounds and two-thirds are women, which represents a greater level of diversity than the corresponding on-campus cohort and the entire university. Additionally, the DE MCS cohort has comparable retention and academic performance compared with the on-campus transfer cohort. Of those who have earned a BS through the DE MCS program, 71% are women and 61% are URM. Overall, these data demonstrate that the hybrid online approach is successful in increasing diversity and provides another viable route in the myriad of STEM pathways. As the first of its kind in a STEM field, the DE MCS program serves as a model for programs seeking to broaden their reach. PMID:27587859

  6. DISCOVERY OF SUBSTRUCTURE IN THE SCATTER-BROADENED IMAGE OF SGR A*

    International Nuclear Information System (INIS)

    We have detected substructure within the smooth scattering disk of the celebrated Galactic center radio source Sagittarius A* (Sgr A*). We observed this structure at 1.3 cm wavelength with the Very Long Baseline Array together with the Green Bank Telescope, on baselines of up to 3000 km, long enough to completely resolve the average scattering disk. Such structure is predicted theoretically as a consequence of refraction by large-scale plasma fluctuations in the interstellar medium. Along with the much-studied θd∝λ2 scaling of angular broadening θd with observing wavelength λ, our observations indicate that the spectrum of interstellar turbulence is shallow with an inner scale larger than 300 km. The substructure is consistent with an intrinsic size of about 1 mas at 1.3 cm wavelength, as inferred from deconvolution of the average scattering. Further observations of the substructure can set stronger constraints on the properties of scattering material and on the intrinsic size of Sgr A*. These constraints will guide our understanding of the effects of scatter broadening and the emission physics near the black hole in images with the Event Horizon Telescope at millimeter wavelengths

  7. Gamma-ray emission spectrum from thermonuclear fusion reactions without intrinsic broadening

    Science.gov (United States)

    Nocente, M.; Källne, J.; Salewski, M.; Tardocchi, M.; Gorini, G.

    2015-11-01

    First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution instruments. An analytical formula for the spectrum from Maxwellian plasmas, which extends to higher temperatures than the results previously available in the literature, has been derived and used to discuss the assumptions and limitations of earlier models. In case of radio-frequency injection, numerical results based on a Monte Carlo method are provided, focusing in particular on improved relations between the peak shift and width from the \\text{d}{{≤ft(\\text{p},γ \\right)}3}\\text{He} reaction and the temperature of protons accelerated by radio-frequency heating. The results presented in this paper significantly improve the accuracy of diagnostic information that can be extracted from the gamma-ray emission spectrum of fusion reactions without intrinsic broadening and are of relevance for applications to high performance plasmas of present and next generation devices.

  8. Global wild annual Lens collection: a potential resource for lentil genetic base broadening and yield enhancement.

    Directory of Open Access Journals (Sweden)

    Mohar Singh

    Full Text Available Crop wild relatives (CWRs are invaluable gene sources for various traits of interest, yet these potential resources are themselves increasingly threatened by the impact of climate change as well as other anthropogenic and socio-economic factors. The prime goal of our research was to cover all aspects of wild Lens genetic resource management like species characterization, agro-morphological evaluation, diversity assessment, and development of representative sets for its enhanced utilization in lentil base broadening and yield improvement initiatives. We characterized and evaluated extensively, the global wild annual Lens taxa, originating from twenty seven counties under two agro-climatic conditions of India consecutively for three cropping seasons. Results on various qualitative and quantitative characters including two foliar diseases showed wide variations for almost all yield attributing traits including multiple disease resistance in the wild species, L. nigricans and L. ervoides accessions. The core set developed from the entire Lens taxa had maximum representation from Turkey and Syria, indicating rich diversity in accessions originating from these regions. Diversity analysis also indicated wide geographical variations across genepool as was reflected in the core set. Potential use of core set, as an initial starting material, for genetic base broadening of cultivated lentil was also suggested.

  9. Broadening Participation of Women and Underrepresented Minorities in STEM through a Hybrid Online Transfer Program

    Science.gov (United States)

    Drew, Jennifer C.; Galindo-Gonzalez, Sebastian; Ardissone, Alexandria N.; Triplett, Eric W.

    2016-01-01

    The Microbiology and Cell Science (MCS) Department at the University of Florida (UF) developed a new model of a 2 + 2 program that uses a hybrid online approach to bring its science, technology, engineering, and mathematics (STEM) curriculum to students. In this paradigm, 2-year graduates transfer as online students into the Distance Education in MCS (DE MCS) bachelor of science program. The program has broadened access to STEM with a steadily increasing enrollment that does not draw students away from existing on-campus programs. Notably, half of the DE MCS students are from underrepresented minority (URM) backgrounds and two-thirds are women, which represents a greater level of diversity than the corresponding on-campus cohort and the entire university. Additionally, the DE MCS cohort has comparable retention and academic performance compared with the on-campus transfer cohort. Of those who have earned a BS through the DE MCS program, 71% are women and 61% are URM. Overall, these data demonstrate that the hybrid online approach is successful in increasing diversity and provides another viable route in the myriad of STEM pathways. As the first of its kind in a STEM field, the DE MCS program serves as a model for programs seeking to broaden their reach. PMID:27587859

  10. Interactive effects of a quantitative and broadened interpretation of the double contingency principle

    International Nuclear Information System (INIS)

    Implementation of the Double Contingency Principle (DCP) for defense-in-depth depends upon measures taken to prevent single failure cause of a criticality accident. In previously published work, the Markov method was shown to be useful for analyzing concurrency, and the independence of changes in process conditions was shown to be expressible quantitatively in terms of a correlation coefficient. Also in previously published work, interpretation of the correlation coefficient was broadened to include the augmentations of negative-definite values and of non-commutativity. In addition, previously published work examined the precepts of reliability analysis and the precepts of correlation analysis to show that the well-trodden path of the former can lead to more perceptive implementation of the latter, while the broadening of the latter can introduce new pathways to the former. In this paper, interactive effects of quantitative assessments of the likelihood, independence, and concurrency aspects of the DCP are examined. When such interactive effects are considered, the quantitative approach becomes more complex, and the use of related approaches, such as reliability analysis, becomes more limited. An illustrative example of the augmentations introduced in previous work is shown with consideration of interactive effects. (authors)

  11. Line facilities outline

    International Nuclear Information System (INIS)

    This book deals with line facilities. The contents of this book are outline line of wire telecommunication ; development of line, classification of section of line and theory of transmission of line, cable line ; structure of line, line of cable in town, line out of town, domestic cable and other lines, Optical communication ; line of optical cable, transmission method, measurement of optical communication and cable of the sea bottom, Equipment of telecommunication line ; telecommunication line facilities and telecommunication of public works, construction of cable line and maintenance and Regulation of line equipment ; regulation on technique, construction and maintenance.

  12. production lines

    Directory of Open Access Journals (Sweden)

    Jingshan Li

    2000-01-01

    Full Text Available In this work, serial production lines with finished goods buffers operating in the pull regime are considered. The machines are assumed to obey Bernoulli reliability model. The problem of satisfying customers demand is addressed. The level of demand satisfaction is quantified by the due-time performance (DTP, which is defined as the probability to ship to the customer a required number of parts during a fixed time interval. Within this scenario, the definitions of DTP bottlenecks are introduced and a method for their identification is developed.

  13. Asymmetric Speed-Dependent Spectral Line Shapes in Cadmium-Foreign-Gas Systems

    International Nuclear Information System (INIS)

    Results of a series of experiments on collisional and speed-dependent effects caused by various foreign gases on the 326.1 nm Cd intercombination line are discussed in detail. Using a laser-induced fluorescence method precise measurements of pressure-broadened profiles of this line perturbed by all rare gases and some molecular gases (H2 , D2 , N2 and CH4 ) were performed in our lab oratory at pressures up to 400 Torr. The line shapes were analyzed in terms of a Speed-Dependent Asymmetric Voigt Profile (SDAVP) and the role of the correlation between pressure broadening rate and emitter velocity as well as of the finite duration of collisions were thoroughly investigated. These effects were found to be particularly important in the cases of perturbation by heavy , i.e. high-polarizability rare-gas atoms (Ar, Kr, Xe). Pressure-broadening and shift rates and the collision-time asymmetry factors as well as effective cross sections for the broadening and shifting of the 326.1 nm Cd line were determined and compared with those calculated on the basis of the van der Waals, Morse and Czuchaj-Stoll potentials. (author)

  14. Two-octave spectral broadening of subnanojoule Cr:forsterite femtosecond laser pulses in tapered fibers

    Science.gov (United States)

    Akimov, D. A.; Ivanov, A. A.; Alfimov, M. V.; Bagayev, S. N.; Birks, T. A.; Wadsworth, W. J.; Russell, P. St. J.; Fedotov, A. B.; Pivtsov, V. S.; Podshivalov, A. A.; Zheltikov, A. M.

    Spectral broadening of femtosecond Cr:forsterite laser pulses is enhanced due to the use of tapered fibers. Supercontinuum generation with unamplified subnanojoule femtosecond Cr:forsterite laser pulses is observed for the first time. With 40-fs 0.6-nJ pulses of 1.25-μm Cr:forsterite laser radiation coupled into a tapered fiber having a taper waist diameter of about 2 μm and a taper waist length of 90 mm, we observed the spectra spanning more than two octaves at the output of the fiber in the regime of anomalous group-velocity dispersion. This result opens the way for the creation of compact femtosecond Cr:forsterite laser plus tapered fiber systems for optical metrology and biomedical applications.

  15. Inhomogeneous broadening of optical transitions of 87Rb atoms in an optical nanofiber trap

    CERN Document Server

    Lee, J; Hoffman, J E; Orozco, L A; Rolston, S L

    2014-01-01

    We experimentally demonstrate optical trapping of 87Rb atoms using a two-color evanescent field around an optical nanofiber. In our trapping geometry, a blue-detuned traveling wave whose polarization is nearly parallel to the polarization of a red-detuned standing wave produce significant vector light shifts that lead to broadening of the absorption profile of a near-resonant beam at the trapping site. A model that includes scalar, vector, and tensor light shifts of the probe transition $5S_{1/2}$-$5P_{3/2}$ from the trapping beams; weighted by the temperature-dependent position of the atoms in the trap qualitatively describe the observed asymmetric profile, and explained differences with previous experiments that used Cs atoms. The model provides a consistent way to extract the number of atoms in the trap.

  16. Coincidence Doppler broadening study of Eurofer 97 irradiated in spallation environment

    Science.gov (United States)

    Sabelová, V.; Kršjak, V.; Kuriplach, J.; Dai, Y.; Slugeň, V.

    2015-03-01

    The behavior of transmutation helium during isochronal annealing of irradiated Eurofer 97 was investigated using coincidence Doppler broadening spectroscopy (CDBS). The investigated ferritic martensitic steel was irradiated in 2000 and 2001 in the frame of the STIP-II project at the Swiss neutron spallation source (SINQ) (irradiation with neutrons and protons) at the Paul Scherrer Institute (PSI). During isochronal annealing experiment, coarsening of vacancy clusters and/or growth of helium bubbles was observed at T ⩾ 500 °C. This process causes an increase of low-momentum annihilation events and related increase of the S parameter during thermal treatment of material. On the other hand, the maximum concentration of helium in small vacancy clusters (Vn) was observed after annealing at 400 °C, where an excellent correlation with the calculated CDBS profiles of Vn + Hem clusters was found.

  17. Diagnostic Technique of Neutron Doppler Broadening for Indirectly-Driven Implosions

    Institute of Scientific and Technical Information of China (English)

    熊勇; 丁永坤; 郑志坚; 陈铭

    2004-01-01

    The neutron Doppler broadening in inertial confinement fusion has been acquired from the time of flight for the neutron, from which the fuel ion temperature can be derived. An ultrafast-quenched plastic scintillation detector was used to measure the time of flight for the neutron at a low-imploded DT neutron yield (5×107 ~ 1 × l08) in the experiment performed on the Shenguang II laser facility. The typical temperatures of ablating targets for indirect drive were around 2.8 keV and the uncertainties were ± 30 % ~± 40%. The detection efficiency of the detector for DT neutrons was calibrated at a K-400 accelerator. The time response function of the detection system was calibrated by imploded neutrons from a DT-filled capsule, which can be regarded as a δ function pulsed neutron source due to its much narrower pulse width than that of the measured neutron time-of-flight spectrum.

  18. Surface hopping with a manifold of electronic states. III. Transients, broadening, and the Marcus picture

    International Nuclear Information System (INIS)

    In a previous paper [Dou et al., J. Chem. Phys. 142, 084110 (2015)], we have introduced a surface hopping (SH) approach to deal with the Anderson-Holstein model. Here, we address some interesting aspects that have not been discussed previously, including transient phenomena and extensions to arbitrary impurity-bath couplings. In particular, in this paper we show that the SH approach captures phonon coherence beyond the secular approximation, and that SH rates agree with Marcus theory at steady state. Finally, we show that, in cases where the electronic tunneling rate depends on nuclear position, a straightforward use of Marcus theory rates yields a useful starting point for capturing level broadening. For a simple such model, we find I-V curves that exhibit negative differential resistance

  19. Cross Functional Career Navigation: The Way to Broaden Your Career Options

    Science.gov (United States)

    Greenhalgh, Todd

    2000-03-01

    In today's rapid paced global environment, broadening career options for career development depends on successful cross-functional career navigation. For scientists and engineers, this means developing a diversity of skills in addition to a strong technical foundation. Fortunately, companies use cross-functional teams as one of the key tools for rapidly developing and commercializing products and services. Participation on these teams carries with it the additional benefit of allowing an individual to develop new skills, and to gain valuable expertise in areas that are critical to the growth of their company, their industry and, most importantly, their career. This talk will outline some of the important cross functional skills that can propel your career ahead and ways in which you can take charge of your career mapping and enhance your value and employability.

  20. Broadening and attenuation of UV laser ablation plumes in background gases

    DEFF Research Database (Denmark)

    Amoruso, S.; Toftmann, B.; Schou, Jørgen

    The expansion of a laser-induced silver plume in a background gas has been studied in a variety of gases ranging from helium, oxygen and argon to xenon. We have measured the angular distribution of the total deposit of silver on an array of quartz crystal microbalances as well as the time-of-flight...... distribution with a Langmuir probe. The angular distribution broadens for all gases except for a minor pressure range for the helium background gas, in which a distinct plume narrowing occurs. The behavior of the collected, ablated silver atoms integrated over the full hemisphere is similar for all gases. This...... integral decreases strongly above a characteristic pressure, which depends on the specific gas. The ion time-of-flight signal shows a clear plume splitting into a fast and a slow component except for the ablation plume in a helium gas. (c) 2005 Elsevier B.V. All rights reserved....

  1. Anisotropy in the angular broadening of Sagittarius A(*) at the galactic center

    Science.gov (United States)

    Yusef-Zadeh, Farhad; Cotton, William; Wardle, Mark; Melia, Fulvio; Roberts, Douglas A.

    1994-01-01

    We present the results of a lambda = 20 cm (VLA) squared observation of the compact Galactic center radio source Sgr A(*). The scatter-broadened image is elongated in the east-west direction, with an axial ratio of 0.56 +/- 0.22 and a position angle of 82 deg +/- 1.8 deg. A similar shape and orientation has been found previously at shorter wavelengths using Very Long Base Interferometry (VLBI) and Very Long Baseline Array (VLBA). Both the major and minor axes follow the lambda squared law appropriate for scattering by turbulence in the intervening medium. We argue that the scattering occurs in thin ionized surface layers of molecular clouds lying in the central 100 pc of the Galaxy. The ionized regions are characterized by electron densities of 10(exp 4)/cu cm and milligauss magnetic field strengths, and are responsible for the diffuse free-free emission and the Faraday rotation in the region.

  2. Amplifying modeling for broad bandwidth pulse in Nd:glass based on hybrid-broaden mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Sujingqin; Lanqin, L; Wenyi, W; Feng, J; Xiaofeng, W; Xiaomin, Z [Research Center of Laser Fusion, China Academy of Engineering Physics, P. O. Box 919-988, Mianyang, China, 621900 (China); Bin, L [School of Computer and Communication Engineering, Southwest Jiaotong University, Chengdu. China, 610031 (China)], E-mail: sujingqin@tom.com

    2008-05-15

    In this paper, the cross relaxation time is proposed to combine the homogeneous and inhomogeneous broaden mechanism for broad bandwidth pulse amplification model. The corresponding velocity equation, which can describe the response of inverse population on upper and low energy level of gain media to different frequency of pulse, is also put forward. The gain saturation and energy relaxation effect are also included in the velocity equation. Code named CPAP has been developed to simulate the amplifying process of broad bandwidth pulse in multi-pass laser system. The amplifying capability of multi-pass laser system is evaluated and gain narrowing and temporal shape distortion are also investigated when bandwidth of pulse and cross relaxation time of gain media are different. Results can benefit the design of high-energy PW laser system in LFRC, CAEP.

  3. Amplifying modeling for broad bandwidth pulse in Nd:glass based on hybrid-broaden mechanism

    Science.gov (United States)

    Su, J.; Liu, L.; Luo, B.; Wang, W.; Jing, F.; Wei, X.; Zhang, X.

    2008-05-01

    In this paper, the cross relaxation time is proposed to combine the homogeneous and inhomogeneous broaden mechanism for broad bandwidth pulse amplification model. The corresponding velocity equation, which can describe the response of inverse population on upper and low energy level of gain media to different frequency of pulse, is also put forward. The gain saturation and energy relaxation effect are also included in the velocity equation. Code named CPAP has been developed to simulate the amplifying process of broad bandwidth pulse in multi-pass laser system. The amplifying capability of multi-pass laser system is evaluated and gain narrowing and temporal shape distortion are also investigated when bandwidth of pulse and cross relaxation time of gain media are different. Results can benefit the design of high-energy PW laser system in LFRC, CAEP.

  4. Amplifying modeling for broad bandwidth pulse in Nd:glass based on hybrid-broaden mechanism

    International Nuclear Information System (INIS)

    In this paper, the cross relaxation time is proposed to combine the homogeneous and inhomogeneous broaden mechanism for broad bandwidth pulse amplification model. The corresponding velocity equation, which can describe the response of inverse population on upper and low energy level of gain media to different frequency of pulse, is also put forward. The gain saturation and energy relaxation effect are also included in the velocity equation. Code named CPAP has been developed to simulate the amplifying process of broad bandwidth pulse in multi-pass laser system. The amplifying capability of multi-pass laser system is evaluated and gain narrowing and temporal shape distortion are also investigated when bandwidth of pulse and cross relaxation time of gain media are different. Results can benefit the design of high-energy PW laser system in LFRC, CAEP

  5. Broadening of mesophase temperature range induced by doping calamitic mesogen with banana-shaped mesogen

    Science.gov (United States)

    Cvetinov, Miroslav; Stojanović, Maja; Obadović, Dušanka; Vajda, Aniko; Fodor-Csorba, Katalin; Eber, Nandor

    2016-03-01

    We have investigated three binary mixtures composed of selected banana-shaped dopant in low concentrations and calamitic mesogen in high. Banana-shaped dopant forms a B7 phase, while the calamitic mesogen exhibit nematic and smectic SmA and SmC phases. The occurring mesophases have been identified by their optical textures. At dopant concentrations of 2.2 and 3.1 mol%, there is evident broadening of nematic and smectic SmA temperature ranges in respect to the pure calamitic compound. Yet, the mixture with dopant concentration of 7 mol% exhibits narrower temperature ranges of mesophases. Increasing dopant concentration caused lowering of all phase transitions temperatures (TI-N, TN-SmA, TSmA-SmC) in all investigated mixtures. Therefore, mixing classic calamitic compounds with novel banana-shaped compound in low concentrations is viable way to attain useful mesophase range for application in industry.

  6. Radiative pT-broadening of high energy quarks and gluons in QCD matter

    CERN Document Server

    Liou, Tseh; Wu, Bin

    2013-01-01

    We study radiative $p_{\\perp}$-broadening of high energy quarks passing through hot and cold QCD matter. With $L$ the length of the matter and $l_{0}$ the size of constituents of the matter we find $\\avg{p_{\\perp}^{2}}$ has both double logarithmic terms, $\\ln^{2}(L/l_{0})$, and single logarithmic terms, $\\ln(L/l_{0})$, coming from gluon radiation induced by the matter. We use a (slight) extension of a formalism developed by B. Zakharov for studying energy loss, a formalism which, for much of our calculation, reduces to a simple dipole scattering analysis. We estimate the radiative contribution to be a sizable correction to the nonradiative value of $\\avg{p_{\\perp}^{2}}$. We also carry out a resummation of the double logarithmic terms that we find, and we briefly discuss running coupling effects which appear here in a rather unusual way.

  7. Coincidence Doppler broadening study of Eurofer 97 irradiated in spallation environment

    International Nuclear Information System (INIS)

    The behavior of transmutation helium during isochronal annealing of irradiated Eurofer 97 was investigated using coincidence Doppler broadening spectroscopy (CDBS). The investigated ferritic martensitic steel was irradiated in 2000 and 2001 in the frame of the STIP-II project at the Swiss neutron spallation source (SINQ) (irradiation with neutrons and protons) at the Paul Scherrer Institute (PSI). During isochronal annealing experiment, coarsening of vacancy clusters and/or growth of helium bubbles was observed at T ⩾ 500 °C. This process causes an increase of low-momentum annihilation events and related increase of the S parameter during thermal treatment of material. On the other hand, the maximum concentration of helium in small vacancy clusters (Vn) was observed after annealing at 400 °C, where an excellent correlation with the calculated CDBS profiles of Vn + Hem clusters was found

  8. Processing of doppler broadening spectra of positron annihilation radiation and its application

    International Nuclear Information System (INIS)

    An unfolding method to obtain intrinsic distributions of positron annihilation radiation from Doppler broadening spectra by means of an iterative method is described. The intrinsic distribution can be fitted into a Gaussian function and an invert parabola function. Electron momentum distribution and Fermi energy can be calculated. Positron annihilation spectra for 13 materials were analyzed. Their momentum distribution and Fermi energy were obtained. The results show that electron momentum distributions for various materials are different and experimental values of Fermi energy for various materials are consistent with theoretical ones. The study on amorphous and crystalline Fe-Si-B alloys indicates that momentum distributions are almost the same, while there is a small difference on Fermi energy

  9. Collision dynamical information from pressure broadening measurements: Application to carbon monoxide

    International Nuclear Information System (INIS)

    Self- and helium-broadened carbon monoxide linewidths have been inverted to obtain state-to-state rate constants using the energy corrected sudden scaling formalism. Selected rotation--rotation and rotation-translation rate constants are discussed as a function of vibrational and rotational levels for the CO--CO and He--CO systems. We find that there is no dependence of the collision dynamics upon the vibrational state of the collision partners up to v = 3. In addition, relaxation in both these systems is found to be dominated by rotation-translation collisions. However they are qualitatively different in their dynamical characteristics and result in signficantly varied state-to-state rate constants. An analysis of the effect of collision partners in the CO--X (X = CO, He, Ne, Ar, Xe, H2) system is presented. Comparisons are made with the available data in the literature

  10. Annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films

    International Nuclear Information System (INIS)

    We systematically investigate the annealing effects on the microwave linewidth broadening of FeCuNbSiB ferromagnetic films with thickness of 100 nm. We correlate the non-uniform residual stress obtained from grazing incidence x-ray diffraction measurements with the ferromagnetic resonance (FMR) linewidth due to effective field inhomogeneities measured from broadband ferromagnetic resonance absorption measurements. We also estimate the annealing temperature effect on the Gilbert and two-magnon scattering contributions to the total ferromagnetic resonance FMR linewidth. We show that the effective field inhomogeneities constitute the main contribution to the microwave linewidth, while this contribution is related to the non-uniform residual stress in the films which is reduced by thermal annealing

  11. Biexcitonic bound and continuum states of homogeneously and inhomogeneously broadened exciton resonances

    DEFF Research Database (Denmark)

    Langbein, W.; Hvam, Jørn Märcher

    2002-01-01

    We investigate the influence of excitonic localization on the corresponding biexcitonic states in GaAs quantum wells by spectrally resolved four-wave mixing. With increasing localization, the biexciton binding energy increases, while the biexciton continuum shifts to higher energies. The localiza......We investigate the influence of excitonic localization on the corresponding biexcitonic states in GaAs quantum wells by spectrally resolved four-wave mixing. With increasing localization, the biexciton binding energy increases, while the biexciton continuum shifts to higher energies. The...... localization leads to an inhomogeneous broadening of the biexciton binding energy and the biexciton continuum edge. Simultaneously, the oscillator strength of the biexciton continuum-edge is reduced. This is interpreted as a result of the different localization of biexcitonic and excitonic states by the random...

  12. Six-wave mixing spectroscopy in a Doppler-broadened cascade four-level system

    Energy Technology Data Exchange (ETDEWEB)

    Niu Jinyan; Wang Ruquan; Wang Bingbing; Wu Lingan; Fu Panming, E-mail: pmfu@aphy.iphy.ac.c [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2009-09-14

    We study six-wave mixing (SWM) spectroscopy based on electromagnetically induced transparency in a Doppler-broadened cascade four-level system. It is found that the SWM spectra are extremely sensitive to the configuration of the incident beams, where the linewidth can be either Doppler-free or very broad, due to the polarization interference of atoms of different velocities. This polarization interference can be controlled in the presence of a strong coupling field. Moreover, SWM can be employed as a new type of Doppler-free Autler-Townes (AT) spectroscopy, which has better spectral resolution than conventional AT spectroscopy. Finally, we also reveal the intrinsic connection between frequency-domain SWM spectroscopy and time-domain photon echoes through studying the time-domain correspondence of SWM.

  13. Effects of Doppler broadening on Autler-Townes splitting in six-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Niu Jinyan [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); School of Mathematics, Physics and Biological Engineering, Inner Mongolia University of Science and Technology, Baotou 014010 (China); Pei Liya; Lu Xiaogang; Wang Ruquan; Wu Lingan; Fu Panming [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-09-15

    The effects of Doppler broadening on Autler-Townes (AT) splitting in six-wave mixing (SWM) are investigated by the dressed-state model. We analyze the velocities at which the atoms are in resonance with the dressed states through Doppler frequency shifting and find that, depending on the wave-number ratio, there may be two resonant velocities which can originate from resonance with one of the dressed states or from resonance with two different dressed states. Based on this model, we discuss a novel type of AT doublet in the SWM spectrum, where macroscopic effects play an important role. Specifically, the existence of resonant peaks requires polarization interference between atoms of different velocities in addition to a change in the number of resonant atoms involved. Our model can also be employed to analyze electromagnetically induced transparency resonance and other types of Doppler-free high-resolution AT spectroscopy.

  14. Dislocation Effects on the Diffraction Line Profiles from Nanocrystalline Domains

    Science.gov (United States)

    Leonardi, Alberto; Scardi, Paolo

    2015-03-01

    A Pd nano-polycrystalline microstructure was simulated by molecular dynamics, including edge or screw dislocations in one of the 50 grains, so as to produce a realistic model of nanocrystalline domain with line defect. The same crystalline domain was also studied, with or without line defects, as a free-standing, isolated nanocrystal. Atomic coordinates of the selected domain were used to generate powder patterns by means of the Debye scattering equation, and these patterns were used as "experimental" data to test existing methods of line profile analysis in controlled condition, i.e., with known type and density of defects. Results show that the Krivolgaz-Wilkens theory of dislocation line broadening qualitatively agrees with the MD model, but errors can be larger than 50 pct. A critical issue arises from the instability of the Krivolgaz-Wilkens model when all line profile parameters are simultaneously refined: reasonable results can be obtained by fixing or restricting some parameters.

  15. Spectral broadening and temporal compression of ∼ 100 fs pulses in air-filled hollow core capillary fibers.

    Science.gov (United States)

    Li, C; Rishad, K P M; Horak, P; Matsuura, Y; Faccio, D

    2014-01-13

    We experimentally study the spectral broadening of intense, ∼ 100 femtosecond laser pulses at 785 nm coupled into different kinds of hollow core capillary fibers, all filled with air at ambient pressure. Differently from observations in other gases, the spectra are broadened with a strong red-shift due to highly efficient intrapulse Raman scattering. Numerical simulations show that such spectra can be explained only by increasing the Raman fraction of the third order nonlinearity close to 100%. Experimentally, these broadened and red-shifted pulses do not generally allow for straightforward compression using, for example, standard chirped mirrors. However, using special hollow fibers that are internally coated with silver and polymer we obtain pulse durations in the sub-20 fs regime with energies up to 300 μJ. PMID:24515074

  16. Experimental measurements of selenium x-ray laser spectral line profiles

    Energy Technology Data Exchange (ETDEWEB)

    Koch, J.A.; MacGowan, B.J.; Da Silva, L.B.; Matthews, D.L.; London, R.A.; Lee, R.W.; Mrowka, S. [Lawrence Livermore National Lab., CA (US); Underwood, J.H.; Batson, P.J. [Lawrence Berkeley Lab., CA (US)

    1993-03-01

    The authors discuss their recent measurements of the spectral width of the 206.38 {Angstrom} x-ray laser transition in Ne-like Se. These measurements used a high-resolution grating spectrometer and were performed over a wide range of laser amplifier lengths. The data have enabled them to extrapolate the intrinsic line width and to observe the effects of gain-narrowing and saturation on the line profile. They find an intrinsic width which is 1.4 times the Doppler width, they observe gain-narrowing in intermediate length amplifiers, and they observe no re-broadening in long, saturated amplifiers. These results suggest that collisional line-broadening has a significant effect on the line profile and saturation behavior of this laser.

  17. Line-of-sight geometrical and instrumental resolution effects on intensity perturbations by sausage modes

    CERN Document Server

    Antolin, Patrick

    2013-01-01

    Diagnostics of MHD waves in the solar atmosphere is a topic which often encounters problems of interpretation, due partly to the high complexity of the solar atmospheric medium. Forward modeling can significantly guide interpretation, bridging the gap between numerical simulations and observations, and increasing the reliability of mode identification for application of MHD seismology. In this work we aim at determining the characteristics of the fast MHD sausage mode in the corona on the modulation of observable quantities such as line intensity and spectral line broadening. Effects of line-of-sight angle, and spatial, temporal and spectral resolutions are considered. We take a cylindrical tube simulating a loop in a low-{\\beta} coronal environment with an optically thin background, and let it oscillate with the fast sausage mode. A parametric study is performed. Among other results, we show that regardless of the ionisation state of the plasma, the variation of spectral line broadening can be significant, e...

  18. Ac Stark splitting in multiphoton excitation of atomic hydrogen in flames: Abnormal peak asymmetry due to pressure broadening

    International Nuclear Information System (INIS)

    A theory of ac Stark (or Autler-Townes) splitting occurring in double optical resonances, one of which is a two-photon transition is developed. Both laser bandwidth and collisional broadening effects are included. Theoretical results are in excellent agreement with Goldsmith's observation of two-peaked structures in the multiphoton excitation spectra of atomic hydrogen in atmospheric-pressure flames. This is believed to be the first study demonstrating that the peak asymmetry in an ac Stark doublet can be reversed due to pressure broadening

  19. A broadened classical master equation approach for nonadiabatic dynamics at metal surfaces: Beyond the weak molecule-metal coupling limit.

    Science.gov (United States)

    Dou, Wenjie; Subotnik, Joseph E

    2016-01-14

    A broadened classical master equation (BCME) is proposed for modeling nonadiabatic dynamics for molecules near metal surfaces over a wide range of parameter values and with arbitrary initial conditions. Compared with a standard classical master equation-which is valid in the limit of weak molecule-metal couplings-this BCME should be valid for both weak and strong molecule-metal couplings. (The BCME can be mapped to a Fokker-Planck equation that captures level broadening correctly.) Finally, our BCME can be solved with a simple surface hopping algorithm; numerical tests of equilibrium and dynamical observables look very promising. PMID:26772563

  20. Ratio of Balmer line to spectrally adjacent emission, from the afterglow of a Z-pinch discharge in hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Jones, W.M.; Healy, M.C.; McCulloch, G.L.

    1987-08-01

    Measurements of line to continuum ratios have been made for the Hsub(..beta..), Hsub(..gamma..), Hsub(delta) and Hsub(epsilon) lines, at different times in the afterglow of a Z-pinch discharge in hydrogen. The contributions of Stark broadening of the lines and atom-electron interaction continuum, to the observed continuum signal, are considered. The electron temperature is estimated with an uncertainty of about +- 10%.