On the nature of the relationship between inhomogeneously broadened phosphorescence and ODMR spectral lines

1988 ◽  
Vol 88 (10) ◽  
pp. 6092-6106 ◽  
Author(s):  
Rodney L. Williamson ◽  
Alvin L. Kwiram
Keyword(s):  
Spectral Lines ◽  
The Relationship

scholarly journals Magnetic activity in the HARPS M dwarf sample

2017 ◽  
Vol 600 ◽  
pp. A13 ◽  
Author(s):  
N. Astudillo-Defru ◽  
X. Delfosse ◽  
X. Bonfils ◽  
T. Forveille ◽  
C. Lovis ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Rotation Period ◽  
Magnetic Activity ◽  
Spectral Lines ◽  
M Dwarfs ◽  
Low Mass Stars ◽  
The Galaxy ◽  
Low Mass ◽  
M Dwarf ◽  
The Relationship

Context. Atmospheric magnetic fields in stars with convective envelopes heat stellar chromospheres, and thus increase the observed flux in the Ca ii H and K doublet. Starting with the historical Mount Wilson monitoring program, these two spectral lines have been widely used to trace stellar magnetic activity, and as a proxy for rotation period (Prot) and consequently for stellar age. Monitoring stellar activity has also become essential in filtering out false-positives due to magnetic activity in extra-solar planet surveys. The Ca ii emission is traditionally quantified through the R'HK-index, which compares the chromospheric flux in the doublet to the overall bolometric flux of the star. Much work has been done to characterize this index for FGK-dwarfs, but M dwarfs – the most numerous stars of the Galaxy – were left out of these analyses and no calibration of their Ca ii H and K emission to an R'HK exists to date. Aims. We set out to characterize the magnetic activity of the low- and very-low-mass stars by providing a calibration of the R'HK-index that extends to the realm of M dwarfs, and by evaluating the relationship between R'HK and the rotation period. Methods. We calibrated the bolometric and photospheric factors for M dwarfs to properly transform the S-index (which compares the flux in the Ca ii H and K lines to a close spectral continuum) into the R'HK. We monitored magnetic activity through the Ca ii H and K emission lines in the HARPS M dwarf sample. Results. The R'HK index, like the fractional X-ray luminosity LX/Lbol, shows a saturated correlation with rotation, with saturation setting in around a ten days rotation period. Above that period, slower rotators show weaker Ca ii activity, as expected. Under that period, the R'HK index saturates to approximately 10-4. Stellar mass modulates the Ca ii activity, with R'HK showing a constant basal activity above 0.6 M⊙ and then decreasing with mass between 0.6 M⊙ and the fully-convective limit of 0.35 M⊙. Short-term variability of the activity correlates with its mean level and stars with higher R'HK indexes show larger R'HK variability, as previously observed for earlier spectral types.

The Experiment Study on Flash Spectrum Produced by Hypervelocity Impact

2015 ◽  
Vol 782 ◽  
pp. 197-203
Author(s):  
Kai Zhang ◽  
Qing Ming Zhang ◽  
Ren Rong Long
Keyword(s):  
Space Debris ◽  
Hypervelocity Impact ◽  
Spectral Lines ◽  
Line Spectrum ◽  
Weapon System ◽  
Flash Intensity ◽  
System A ◽  
Flash Spectrum ◽  
The Relationship ◽  
Important Significance

It is an inevitable phenomenon that flash is generated in the process of hypervelocity impact. The research on impact flash is of important significance for assessing the collision between space debris and spacecraft, identifying the material properties on the surface of planet, evaluating the damage of weapon system. A measurement system was built in order to acquire flash spectrum ranging in wavelength from 200 to 1100nm. The relationship between flash intensity and impact velocity was studied. The spectrum consists of line spectrum and continuous spectrum. Line spectrum mainly concentrates in the range of 200-500nm. The spectral lines of the elements were identified. The strong flash happens within 2.2ms after beginning to impact. In addition, the electron temperature of plasma produced in hypervelocity impact is calculated by spectral method, and compared with the temperature measured by Langmuir three probes.

scholarly journals The Binarity of Early-type Stars from LAMOST Medium-resolution Spectroscopic Survey

2021 ◽  
Author(s):  
Yanjun Guo ◽  
Jiao Li ◽  
Jianping Xiong ◽  
Jiangdan Li ◽  
Luqian Wang ◽  
...  
Keyword(s):  
Orbital Period ◽  
Likelihood Estimation ◽  
Spectral Lines ◽  
Spectroscopic Binaries ◽  
Early Type ◽  
Mass Ratio ◽  
Medium Resolution ◽  
Early Type Stars ◽  
Relationship Of ◽  
The Relationship

Abstract Massive binaries play significant roles in many fields. Identification of massive stars, particularly massive binaries, is of great importance. In this paper, by adopting the technique of measuring the equivalent widths of several spectral lines, we identified 9,382 early-type stars from LAMOST medium-resolution survey and divided the sample into four groups, T1 ($\sim$O-B4), T2 ($\sim$B5), T3 ($\sim$B7), and T4 ($\sim$B8-A). The relative radial velocities $RV_{\rm rel}$ were calculated using the Maximum Likelihood Estimation. The stars with significant changes of $RV_{\rm rel}$ and at least larger than 15.57km s$^{-1}$ were identified as spectroscopic binaries. We found that the observed spectroscopic binary fractions for the four groups are $24.6\%\pm0.5\%$, $20.8\%\pm0.6\%$, $13.7\%\pm0.3\%$, and $7.4\%\pm0.3\%$, respectively. Assuming that orbital period ($P$) and mass ratio ($q$) have intrinsic distributions as $f(P) \propto P^\pi$ (1\textless$P$\textless1000 days) and $f(q) \propto q^\kappa$ (0.1\textless$q$\textless1), respectively, we conducted a series of Monte-Carlo simulations to correct observational biases for estimating the intrinsic multiplicity properties. The results show that the intrinsic binary fractions for the four groups are 68$\%\pm8\%$, 52$\%\pm3\%$, 44$\%\pm6\%$, and 44$\%\pm6\%$, respectively. The best estimated values for $\pi$ are -1$\pm0.1$, -1.1$\pm0.05$, -1.1$\pm0.1$, and -0.6$\pm0.05$, respectively. The $\kappa$ cannot be constrained for groups T1 and T2 and is -2.4$\pm0.3$ for group T3 and -1.6$\pm0.3$ for group T4. We confirmed the relationship of a decreasing trend in binary fractions towards late-type stars. No correlation between the spectral type and the orbital period distribution has been found yet, possibly due to the limitation of observational cadence.

scholarly journals Determination and Study the Energy Characteristics of Vibrational-Rotational Levels and Spectral Lines of GaF, GaCl, GaBr and GaI for Ground State

2015 ◽  
Vol 50 ◽  
pp. 96-112
Author(s):  
Adil Nameh Ayaash
Keyword(s):  
Quantum Number ◽  
Computer Model ◽  
Ground State ◽  
Theoretical Study ◽  
Rotational Quantum Number ◽  
Spectral Lines ◽  
Vibrational Quantum Number ◽  
Energy Characteristics ◽  
Number Increase ◽  
The Relationship

A theoretical study of four gallium monohalides molecules (GaF, GaCl, GaBr and GaI) of ground state 1∑+ by using computer model is presented to study the energy characteristics of vibrational-rotational levels as a function of the vibrational and rotational quantum number , respectively. The calculations has been performed to examine the vibrational-rotational characteristics of some gallium halides molecules. These calculations appeared that all energies (Gv, Ev,J, and Fv,J) increase with increasing vibrational and rotational quantum number and by increasing the vibrational quantum number, and by increasing the vibrational quantum number, the vibrational constant will decrease. Also theoretical study of spectra of these molecules for ground state 1∑+ has been carried out. The values of spectral lines R(J) and P(J) were calculated and the relationship between the spectral lines and the rotational quantum number was established. The results appeared the spectra line values R(J) increases when the values of rotational quantum number decrease but the spectra line values P(J) decrease when the values of rotational quantum number increase, also the spectra line values P(J) decrease when the values of (m) increase, while the values of R(J) increase at first, then decrease showing Fortrar parabola.

The Stokes' Shift in Impurity Spectral Lines. II. Relationship to the Adiabatic Approximation Approach

1972 ◽  
Vol 50 (3) ◽  
pp. 231-236 ◽  
Author(s):  
Robert Barrie ◽  
I. W. Sharpe ◽  
B. L. Jones
Keyword(s):  
Canonical Transformation ◽  
Adiabatic Approximation ◽  
Stokes Shift ◽  
Spectral Lines ◽  
Approximation Approach ◽  
The Relationship

The derivation of the Stokes' shift has been performed without making the adiabatic approximation. A canonical transformation is used to show the relationship between that method and the more usual one in which the adiabatic approximation is made.

Binary Dinitrogen Complexes of Rhodium, Rh(N2)n (where n = 1–4), in Low Temperature Matrices

1973 ◽  
Vol 51 (20) ◽  
pp. 3332-3343 ◽  
Author(s):  
Geoffrey A. Ozin ◽  
Anthony Vander Voet
Keyword(s):  
Field Approximation ◽  
Spectral Lines ◽  
Site Symmetry ◽  
Reaction Products ◽  
Solid Nitrogen ◽  
Dinitrogen Complexes ◽  
The Individual ◽  
A Site ◽  
Solid Argon ◽  
The Relationship

The products of the cocondensation reactions of Rh atoms with N2 and N2/Ar mixtures at 10 °K are investigated by matrix isolation infrared spectroscopy and are shown to be binary dinitrogen complexes of the form Rh(N2)n. Examination of the reaction products in pure 14N2, 15N2, 14N2/15N2, and in dilute Ar/14N2, Ar/14N2/15N2, and Ar/14N2/14N15N/15N2 matrices establish the values of n to be 1–4. Isotopic frequencies are computed for the NN stretching modes of the individual dinitrogen complexes on the basis of the Cotton–Kraihanzel (C.K.) force field approximation and are found to be in close agreement with observed values. Trends in the best fit C.K. force constants for Rh(N2)n (n = 1–4) and the thermodynamic stabilities of the individual complexes as indicated by the function ΔHcn, a measure of the enthalpy of decomposition, are discussed. Comparisons are made between Ni(N2)n and Rh(N2)n (where n = 1–4). The structure of Rh(N2)4 in solid nitrogen is shown to be that of a distorted tetrahedron. Calculations show that a site symmetry of D2d for Rh(N2)4 satisfactorily accounts for all of the spectral lines observed for the complex in nitrogen. In solid argon, Rh(N2)4 appears to have an approximately regular tetrahedral structure. The relationship between RhN2 and N2 chemisorbed on Rh metal is discussed and compared with the analogous Ni–, Pd–, and Pt–nitrogen systems.

scholarly journals Stark Broadening of Isolated Lines from Multiply Charged Ions

1977 ◽  
Vol 43 ◽  
pp. 24-24
Author(s):  
J. D. Hey
Keyword(s):  
Spectral Lines ◽  
Oscillator Strengths ◽  
Stark Broadening ◽  
Multiply Charged Ions ◽  
Multiply Charged ◽  
Configuration Mixing ◽  
Lower Temperature ◽  
The Relationship ◽  
Bound Electrons ◽  
Charged Ions

When calculating the Stark widths of isolated lines of multiply charged ions with several bound electrons, radiated by dense, hot plasmas, the existing theories of Stark broadening which have been applied mainly to lower-temperature measurements on singly-ionized species, need to be modified in several respects. These modifications involve taking more careful account of the complexities of the particular atomic structure: e.g. deviations from LS coupling, configuration mixing, and optically forbidden transitons. Earlier work, showing explicitly the relationship between the Stark widths and the oscillator strengths for the collision-induced transitions Which contribute to the width, is extended. Some of the principles involved will be discussed and, if time permits, comparison will be made between calculations and the results of several critically selected experiments on spectral lines in the near UV (2000-3500 Å).

DISCUSSION ON THE SELF-ABSORPTION OF SODIUM 330.3 NM RESONANCE LINE FOR THE SPHERICAL GEOMETRY PLASMA

2010 ◽  
Vol 24 (21) ◽  
pp. 2267-2275 ◽  
Author(s):  
JIAN HE ◽  
LIXIN XIA
Keyword(s):  
General Expression ◽  
Calculation Method ◽  
Resonance Line ◽  
Spherical Geometry ◽  
Spectral Lines ◽  
The Self ◽  
The Real ◽  
Relationship Of ◽  
The Relationship ◽  
Escape Factor

In this letter, self-absorption is discussed using the concept of escape factor. The calculation method of the escape factor for spherical geometry plasma is discussed. For the spherical geometry, the escape factors Λ(r) at any position r in a spherical geometry plasma (with the radius R) for Lorentzian and Holtsmarkian profiles are calculated, and a general expression is obtained. As an example, for the sodium 330.3 nm resonance line, the total radiance and the real radiance are calculated, and the self-absorption for the resonance line is discussed. This discussion will be useful for the study of the relationship of escape factor and the self-absorption of spectral lines for any geometries.

Interstellar gas in the central region of the Galaxy

1967 ◽  
Vol 31 ◽  
pp. 239-251 ◽  
Author(s):  
F. J. Kerr
Keyword(s):  
Central Region ◽  
Galactic Plane ◽  
Neutral Hydrogen ◽  
Continuum Emission ◽  
Galactic Centre ◽  
Interstellar Gas ◽  
Hydrogen Recombination ◽  
The Galaxy ◽  
Centre Region ◽  
The Relationship

A review is given of information on the galactic-centre region obtained from recent observations of the 21-cm line from neutral hydrogen, the 18-cm group of OH lines, a hydrogen recombination line at 6 cm wavelength, and the continuum emission from ionized hydrogen.Both inward and outward motions are important in this region, in addition to rotation. Several types of observation indicate the presence of material in features inclined to the galactic plane. The relationship between the H and OH concentrations is not yet clear, but a rough picture of the central region can be proposed.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

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