550 research outputs found
Vera Kistiakowsky edited transcript, 1976 April–September
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Discovery of Tantalum, Rhenium, Osmium, and Iridium Isotopes
Currently, thirty-eight tantalum, thirty-eight rhenium, thirty-nine osmium,
and thirty-eight iridium, isotopes have been observed and the discovery of
these isotopes is discussed here. For each isotope a brief synopsis of the
first refereed publication, including the production and identification method,
is presented.Comment: To be published in At. Data Nucl. Data Table
Backward pion-nucleon scattering
A global analysis of the world data on differential cross sections and
polarization asymmetries of backward pion-nucleon scattering for invariant
collision energies above 3 GeV is performed in a Regge model. Including the
, , and trajectories, we
reproduce both angular distributions and polarization data for small values of
the Mandelstam variable , in contrast to previous analyses. The model
amplitude is used to obtain evidence for baryon resonances with mass below 3
GeV. Our analysis suggests a resonance with a mass of 2.83 GeV as
member of the trajectory from the corresponding Chew-Frautschi
plot.Comment: 12 pages, 16 figure
MASH-II: More Planetary Nebulae from the AAO/UKST H\alpha Survey
We present a supplement to the Macquarie/AAO/Strasbourg H planetary
nebulae (PNe) catalogue (MASH), which we denote MASH-II. The supplement
consists of over 300 true, likely and possible new Galactic PNe found after
re-examination of the entire AAO/UKST H survey of the southern Galactic
Plane in digital form. We have spectroscopically confirmed over 240 of these
new candidates as bona-fide PNe and we include other high quality candidates
awaiting spectroscopic confirmation as possible PNe. These latest discoveries
largely comprise two distinct groups: small, star-like or moderately resolved
PNe at one end and mostly large, extremely low surface brightness PNe at the
other. Neither group were easy to discover from simple visual scrutiny of the
original survey exposures as for MASH but were relatively straightforward to
uncover from the digital images via application of semi-automated discovery
techniques. We suspect the few PNe still hidden in the H survey will
lie outside our search criteria or be difficult to find.Comment: 10 pages, 8 figures. Accepted for publication in MNRAS. Catalogue
will be available from vizie
On the curvature in logarithmic plots of rate coefficients for chemical reactions
In terms of the reduced potential energy barrier ζ = ΔuTS/kT, the rate coefficients for chemical reactions are usually expressed as proportional to e-ζ. The coupling between vibrational modes of the medium to the reaction coordinate leads to a proportionality of the regularized gamma function of Euler Q(a,ζ) = Γ(a,ζ)/Γ(a), with a being the number of modes coupled to the reaction coordinate. In this work, the experimental rate coefficients at various temperatures for several chemical reactions were fitted to the theoretical expression in terms of Q(a,ζ) to determine the extent of its validity and generality. The new expression affords lower deviations from the experimental points in 29 cases out of 38 and it accounts for the curvature in the logarithmic plots of rate coefficients versus inverse temperature. In the absence of tunneling, conventional theories predict the curvature of these plots to be identically zero
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Multiple Correlations and High Tranverse Momentum Jets in 147-GeV/c pi- p Interactions
We examine multiparticle correlations in a {pi}{sup -}p experiment at 147 GeV/c performed by the Proportional Hybrid System Consortium. The major aim of this paper is to demonstrate the existence of clusters in our data. We use different statistical algorithms to assemble into clusters the particles in each event which are associated by virtue of small relative angles. We find that these clusters are stable against different choices of metric and/or algorithm, and reproduce the effects previously observed in the data corresponding to clusters. Some of these clusters have properties similar to high p{sub T} jets. A detailed study of these jet-like clusters is described, and comparisons with some counter experiments are discussed
Photodissociation of ClNO in the 2 1A' state: computational and experimental NO product state distributions.
Ultrafast photodissociation of the 2 (1)A' state of ClNO, which has an absorption spectrum peaking at 335 nm, is studied by computational and experimental methods. New potential-energy surfaces are calculated for the 1 and 2 (1)A' states at the multireference configuration interaction (MRCI) level. Wavepacket dynamics simulations performed both exactly and by using the multiconfiguration time-dependent Hartree method yield essentially identical results. Transition dipole moments at a range of geometries are included in these calculations to correctly model the excitation. Vibrational and rotational state distributions of the NO product are obtained both computationally by analysing the quantum flux on the 2 (1)A' surface and experimentally by use of 3D resonant multiphoton ionisation (REMPI), a variant of the velocity map imaging technique. The nascent NO is found to be only marginally vibrationally excited, with 91% formed in v=0. The calculated NO rotational distribution peaks in the j=45-55 region, which compares favourably to experiment
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