ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Intermultiplet transfers of excited sodium atoms induced by nitrogen molecules (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 89 (1988), S. 251-256 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The predictions of a multiple curve crossing model (MCC) were compared to experimental observations of various intermultiplet transfers in thermal energy Na/N2 collisions. This includes comparisons to the energy dependence and the absolute value of the Na(4D→5S) cross section that was measured in the experimental section of the present work using a crossed beam apparatus. This also includes comparisons with beam data available in the literature. These last experimental results are not always directly comparable to the calculated cross sections. Deconvolution or simulation procedures are then needed. The general agreement between the MCC calculations and the experimental results is good. In many cases it is much better than a factor 2. The cases or disagreement were discussed carefully, and each of them can be attributable to uncertainties in the experiment or in the procedures of deconvolutions and simulations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455518
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Collisions of excited alkali atoms with O2. I. Intermultiplet transfer (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 87 (1987), S. 2084-2089 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The cross sections for the Rb(7S→5D), Rb(5D→7S), and Na(4D→5S) collisional transfers induced by O2 have been measured in absolute values as a function of the collision energy using a crossed beam apparatus. The experimental data have been compared with the predictions given by a multiple curve-crossing model where the symmetries of the states formed by the colliding alkali-metal atom–O2 system as well as the molecular orientation are considered. Good agreement is observed between experimental and calculated cross sections. This tends to show that in spite of its approximations, a multiple curve-crossing model would be useful to obtain fairly accurate informations about collisional processes involving alkali atoms with as much as 4 eV electronic excitation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.453183
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Collisions of excited alkali atoms with O2. III. Visualization of the collision path (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 6866-6872 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Inelastic scattering of electronically excited Na atoms by ground state O2 molecules was studied theoretically using a multiple-curve-crossing model. The movement of the collisional system within the potential grid describing the Na–O2 and Na+– O−2 pairs was visualized for two initial electronic states of Na (5S and 4D) at collision energies ranging between 0.2 and 1.0 eV. Visualization of the collision path was used to better understand prominent features of the redistribution of energy by collision within the system. Knowledge of the collision path for inelastic scattering also helped in discussing a competing reactive channel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457355
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Collisions of excited alkali atoms with O2. II. Reactive scattering (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 2398-2404 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Inelastic and reactive channels in excited Na atom/ O2 molecule collisions have been included into a single model based on multiple crossings between curves of the Na(n,l)–O2, Na+–O−2 (X 2Πg), and Na+–O−2 (A 2Πu) systems. Additionally, estimation is provided of the excited ion pair surface Na+–O−2 (A2Πu) in collinear geometry. This paper is essentially concerned with the reaction of Na(4D) giving NaO as product, a reaction where experimental results are available, but where no reaction mechanism has been proposed so far. When the reaction proceeds via the excited ion pair Na+ –O−2 (A 2Πu) , the calculations indicate that the cross section has a threshold collision energy and that impact parameters smaller than 1 A(ring) are involved. These features are consistent with the experimental data. This suggests that the excited ion pair Na+–O−2 (A2 Πu) is a likely intermediate in the reaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454023
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Constraints on the duration and freshwater release of Heinrich event 4 through isotope modelling (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 432 (2004), S. 379-382 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Heinrich events—abrupt climate cooling events due to ice-sheet instability that occurred during the last glacial period—are recorded in sediment cores throughout the North Atlantic Ocean. Modelling studies have described likely physical mechanisms for these events, but the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature03059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A cylinder-to-sphere Fourier view factor model for azimuthal asymmetry studies in cylindrical hohlraums (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 282-292 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This work addresses the analytical calculation of the irradiation coming from a cylindrical surface to a spherical one. This exact solution of the x-ray transport equation allows one to connect the emitted and the received fluxes, expanded as Fourier modes, by coefficients called Fourier view factors. Such a calculation is well suited to a symmetry study in the Laser Megajoule configuration [P.-A. Holstein, M. André, M. Casanova et al., C. R. Acad. Sci. Paris 1, 693 (2000)] where a cylindrical hohlraum and a spherical capsule are irradiated. Indeed, this 60 quad laser system induces an azimuthal asymmetry of the hohlraum lighting depending on the laser focal spot size. Thus, the Fourier view factors allow one to express the modes of the capsule irradiation as functions of the elliptic spot dimensions. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1418432
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Near-resonant electronic-to-rotational energy transfer in Rb(7S→5D)–H2, D2 collisions at thermal energy (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 1451-1458 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The intermultiplet transfer Rb (7S→5D) induced by H2, D2, and He has been studied as a function of collision velocity using a crossed beam apparatus for which the initial rotational distribution of the molecular perturber was determined. A calibration using the blackbody induced redistribution of the excited states populations in the Rb beam allowed the absolute value of the cross section to be obtained. A situation where a near resonance exists (perturber H2) is compared with situations where near resonances do not occur (perturbers D2 and He). For low collision velocities (VR≤4000 m/s), the near-resonant process Rb(7S)+H2( j=1)→Rb(5D)+H2( j=3) has a much larger cross section than competing nonresonant processes (rotationally elastic or inelastic). Its cross section decreases with the relative velocity as ∼1/V2R. This behavior is compared with the predictions of two theoretical models (the impulse approximation model, which leads to a quantitative comparison with the measured velocity dependence, and the long range forces model). Above 4000 m/s the behavior of H2 closely resembles that of D2 and He where no near resonances exist. This suggests that for high velocities, the intermultiplet transfer is due to nonresonant processes only.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450489
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Role of the thermohaline circulation in the abrupt warming after Heinrich events (1994)
    [s.l.] : Nature Publishing Group
    Nature 372 (1994), S. 162-164 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The so-called 'Dansgaard-Oeschger events' were first seen as abrupt shifts in the oxygen isotope ratio of three Greenland ice cores, from Camp Century, Dye 3 and Renland. Two new cores, GRIP1'7 and GISP28, recently confirmed these rapid excursions in 518O, which reflect changes in the temperature ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/372162a0
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Nonlinear variability of the climatic system from singular and power spectra of Late Quaternary records (1994)
    Springer
    Climate dynamics 9 (1994), S. 371-389 
    Details
    ISSN: 1432-0894
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Stable-isotope records from seven marine cores and one ice core provide invaluable information on the intricate behavior of the climatic system over time scales of 104 to 105 years. These records, in conjunction with a simple coupled climate model, help us understand major mechanisms of paleoclimatic variability. The time intervals covered by the records include the last glacial-interglacial cycle. In spite of the difference in the nature of the records, common features are revealed by advanced spectral-analysis tools. The dominant features are the presence of orbital frequencies, on the one hand, and a low number of internal degrees of freedom, on the other. The climatic system appears therefore to act on the Quaternary time scales considered as a forced nonlinear oscillator. The internal mechanisms giving rise to the aperiodic oscillations include ice-albedo feedback, precipitation-temperature feedback, and interactions between the ice sheets and the bedrock.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207933
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    facet.materialart.
    Unknown
    Last Glacial Maximum CO2 and δ13C successfully reconciled (2011)
    Wiley
    Details
    Publication Date: 2011-01-25
    Description: During the Last Glacial Maximum (LGM, ∼21,000 years ago) the cold climate was strongly tied to low atmospheric CO2 concentration (∼190 ppm). Although it is generally assumed that this low CO2 was due to an expansion of the oceanic carbon reservoir, simulating the glacial level has remained a challenge especially with the additional δ13C constraint. Indeed the LGM carbon cycle was also characterized by a modern-like δ13C in the atmosphere and a higher surface to deep Atlantic δ13C gradient indicating probable changes in the thermohaline circulation. Here we show with a model of intermediate complexity, that adding three oceanic mechanisms: brine induced stratification, stratification-dependant diffusion and iron fertilization to the standard glacial simulation (which includes sea level drop, temperature change, carbonate compensation and terrestrial carbon release) decreases CO2 down to the glacial value of ∼190 ppm and simultaneously matches glacial atmospheric and oceanic δ13C inferred from proxy data. LGM CO2 and δ13C can at last be successfully reconciled.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...