ACCESS OF EXCITED STATES TO THE CONTINUUM

1985 ◽  
Vol 46 (C7) ◽  
pp. C7-409-C7-412 ◽  
Author(s):  
C. K. Jørgensen
Keyword(s):  
Excited States ◽  
The Continuum

Non L.T.E. Properties of Quasistationary Oxygen Plasmas

1976 ◽  
Vol 31 (3-4) ◽  
pp. 362-368 ◽  
Author(s):  
M. Cacciatore ◽  
M. Capitelli
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Ground State ◽  
Radiative Recombination ◽  
Local Thermodynamic Equilibrium ◽  
Collisional Radiative Model ◽  
Radiative Model ◽  
Ionization Coefficients ◽  
Selection Of ◽  
The Continuum

The non L.T.E. (local thermodynamic equilibrium) properties of optically thin and thick quasistationary oxygen plasmas have been calculated for the temperature range k T = 0.5 - 1.5 eV and for the electron density interval 108 - 1016 cm-3 , by using the collisional-radiative model of Bates, Kingston and McWhirther. The results include1 the coefficients r0(i) and r1(i), which represent the contribution to the population density of the ith quantum level from the continuum and from the ground state, respectively2 the values of α and S, which are the collisional-radiative recombination and ionization coefficients, respectively. The accuracy of the present results is discussed in connection with the adopted plasma model and with the selection of the collisional cross sections for forbidden and allowed transitions. A discussion is also presented of the influence of the two low lying excited states of oxygen atoms (i.e. the states 2p41D, 2p41S) on the non L.T.E. properties of these plasmas. A satisfactory agreement is found with the calculations of Julienne et al. and with the experimental results of Jones.

scholarly journals THE SUPPRESSION OF πNN(1535) COUPLING IN QCD

1998 ◽  
Vol 13 (34) ◽  
pp. 2763-2770 ◽  
Author(s):  
SHI-LIN ZHU
Keyword(s):  
Correlation Function ◽  
Excited States ◽  
Sum Rules ◽  
Qcd Sum Rules ◽  
Borel Transform ◽  
Point Correlation ◽  
Point Correlation Function ◽  
The Continuum

The lightcone QCD sum rules are employed to calculate the πNN(1535) coupling gπNN*.We study the two-point correlation function of two nucleon currents sandwiched between the vacuum and the pion state. The contribution from the excited states and the continuum is subtracted from the double Borel transform with respect to the nucleon and N(1535) momenta, [Formula: see text]. Our calculation shows that the πNN(1535) coupling is strongly suppressed.

Kontinuumsstrahlung des einfach ionisierten Helium-Plasmas im Spektralbereich von 300 nm bis 650 nm / Continuum Radiation of a Single Ionized Helium-Plasma in the Spectral Range 300 nm to 650 nm

1975 ◽  
Vol 30 (11) ◽  
pp. 1413-1424
Author(s):  
D. Einfeld ◽  
G. Sauerbrey
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Discharge Current ◽  
Principal Quantum Number ◽  
The State ◽  
Helium Plasma ◽  
Relative Uncertainty ◽  
Continuum Radiation ◽  
Good Agreement ◽  
The Continuum

The radiation emitted from a wall stabilized helium-plasma (ne ≈ 3 • 1022 m-3, T ≈ 38 000 K, duration of constant discharge current 0.4 ms) was investigated in the wavelength range 300 nm to 650 nm. From the emission coefficients of the continuum radiation Gaunt factors for the state with the principal quantum number 3 and the state 2 3P were determined. Gaunt factors for the terms 2 1S, 2 1P, 2 3S and 2 3P were calculated from the transition probalilities of highly excited states. Agreement to within the accuracy of the measurement was found between the experimental results and the Gaunt factors evaluated from the photoionisation cross-sections calculated by Goldberg. The Gaunt factors for the states 2 1P and 2 3S according to Anderson and Griem are in good agreement with our results; for the terms 2 3P and 2 1S a discrepancy exists. With the Gaunt factors reported here electron densities in a helium-plasma can be determined with a relative uncertainty of 10%. The ξ-factor calculated by Kriener and Schlüter could be confirmed, if Bremsstrahlung of neutral atoms is neglected

scholarly journals The peculiar chemistry of the inner ejecta of Eta Carina

2019 ◽  
Vol 490 (2) ◽  
pp. 1570-1580 ◽  
Author(s):  
Cristobal Bordiu ◽  
J Ricardo Rizzo
Keyword(s):  
Point Source ◽  
Excited States ◽  
Line Emission ◽  
Vibrationally Excited ◽  
Apparent Lack ◽  
North West ◽  
Inner Region ◽  
Η Car ◽  
Better Than ◽  
The Continuum

ABSTRACT We investigated continuum and molecular line emission of four species (CO, HCN, H13CN, and HCO+) at 0.8 mm in the inner region around η Car, using ALMA archival observations at a resolution better than 0.2 arcsec. We report the discovery of an asymmetric extended structure north-west of the star, independent from the continuum point source. The structure is only traced by continuum and HCO+, and not detected in the other lines. Kinematics of this structure reveal that the HCO+ gas likely arises from ejecta expelled in the 1890s eruption. The ejecta is propagating outwards within the cavity produced by the current wind–wind interaction of η Car A and its companion. Chemical analysis of the ejecta reveals an apparent lack of CO and nitrogen-bearing species. We explore possible explanations for this peculiar chemistry, that differentiates this structure from the ejecta of the Great Eruption, rich in HCN and H13CN. We also report an absorption component near the continuum point source, only traced by HCN and H13CN in their vibrational-ground and vibrationally excited states. This absorbing gas is attributed to a hot bullet of N-enriched material expelled at a projected velocity of 40 km s−1.

scholarly journals An SCF-stabilization approach to excited states embedded in the continuum

1977 ◽  
Vol 67 (5) ◽  
pp. 2178 ◽  
Author(s):  
C. F. Bender ◽  
Vincent McKoy ◽  
Ernest R. Davidson
Keyword(s):  
Excited States ◽  
The Continuum

scholarly journals Excited and exotic bottomonium spectroscopy from lattice QCD

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Sinéad M. Ryan ◽  
◽  
David J. Wilson
Keyword(s):  
Lattice Qcd ◽  
Heavy Quark ◽  
Quark Model ◽  
Excited States ◽  
Ground State ◽  
Charm Quark ◽  
Spin Parity ◽  
Quantum Numbers ◽  
Dominant Operator ◽  
The Continuum

Abstract We explore the spectrum of excited and exotic bottomonia using lattice QCD. Highly excited states are identified with masses up to 11,000 MeV, many of which can be grouped into supermultiplets matching those of the quark model while exotic spin-parity-charge-conjugation quantum numbers JPC = 0+−, 1−+, 2+− that cannot be formed from $$ \overline{q}q $$ q ¯ q alone are also identified. Single-meson operator constructions are used that have good JPC in the continuum, these are found to overlap well onto heavy quark states up to J ≤ 4. A continuum JPC is assigned to each level, based on the distribution amongst lattice irreps and dominant operator overlaps. States with a dominant gluonic component are identified and form a hybrid supermultiplet with JPC = (0, 1, 2)−+, 1−−, approximately 1500 MeV above the ground-state ηb, similar to previous computations with light, strange and charm quark systems.

C. The Continuous Spectrum of Pulsating Variable Stars

1967 ◽  
Vol 28 ◽  
pp. 177-206
Author(s):  
J. B. Oke ◽  
C. A. Whitney
Keyword(s):  
Continuous Spectrum ◽  
Variable Stars ◽  
Velocity Fields ◽  
The Other ◽  
Line Spectrum ◽  
Direct Information ◽  
Thermodynamic Structure ◽  
Diagnostic Interpretation ◽  
Pulsating Variable Stars ◽  
The Continuum

Pecker:The topic to be considered today is the continuous spectrum of certain stars, whose variability we attribute to a pulsation of some part of their structure. Obviously, this continuous spectrum provides a test of the pulsation theory to the extent that the continuum is completely and accurately observed and that we can analyse it to infer the structure of the star producing it. The continuum is one of the two possible spectral observations; the other is the line spectrum. It is obvious that from studies of the continuum alone, we obtain no direct information on the velocity fields in the star. We obtain information only on the thermodynamic structure of the photospheric layers of these stars–the photospheric layers being defined as those from which the observed continuum directly arises. So the problems arising in a study of the continuum are of two general kinds: completeness of observation, and adequacy of diagnostic interpretation. I will make a few comments on these, then turn the meeting over to Oke and Whitney.

Photo-electric Hβ and uvby photometry

1966 ◽  
Vol 24 ◽  
pp. 170-180
Author(s):  
D. L. Crawford
Keyword(s):  
Narrow Band ◽  
Line Strength ◽  
Interference Filter ◽  
B Stars ◽  
Relative Line ◽  
The Mean ◽  
F Stars ◽  
Two Parameters ◽  
Filter Photometry ◽  
The Continuum

Early in the 1950's Strömgren (1, 2, 3, 4, 5) introduced medium to narrow-band interference filter photometry at the McDonald Observatory. He used six interference filters to obtain two parameters of astrophysical interest. These parameters he calledlandc, for line and continuum hydrogen absorption. The first measured empirically the absorption line strength of Hβby means of a filter of half width 35Å centered on Hβand compared to the mean of two filters situated in the continuum near Hβ. The second index measured empirically the Balmer discontinuity by means of a filter situated below the Balmer discontinuity and two above it. He showed that these two indices could accurately predict the spectral type and luminosity of both B stars and A and F stars. He later derived (6) an indexmfrom the same filters. This index was a measure of the relative line blanketing near 4100Å compared to two filters above 4500Å. These three indices confirmed earlier work by many people, including Lindblad and Becker. References to this earlier work and to the systems discussed today can be found in Strömgren's article inBasic Astronomical Data(7).

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