Satellites of the resonance transitions of alkali atoms in mixtures with CF4

2021 ◽  
Vol 258 ◽  
pp. 107339
Author(s):  
V.A. Alekseev ◽  
A.A. Pastor ◽  
A.S. Pazgalev ◽  
P.A. Petrov ◽  
P.Yu. Serdobintsev ◽  
...  
Keyword(s):  
Alkali Atoms ◽  
Resonance Transitions

scholarly journals Silicon in the solar corona

1965 ◽  
Vol 23 ◽  
pp. 115-123
Author(s):  
K. G. Widing ◽  
J. R. Porter
Keyword(s):  
Solar Corona ◽  
Relative Intensity ◽  
Line Emission ◽  
X Ray ◽  
Resonance Transitions ◽  
Spectral Ranges

Resonance lines of coronal ions of silicon are prominent in the spectral ranges 40–62 Å and 254–356 Å.An unexpected feature of the soft X-ray spectrum is the weakness or absence of the resonance lines of iron in ionization stages XI through XV.A second feature is the prominence of lines of the type (3d → 2p) relative to the resonance transitions (3p → 2s) in Li-like and Beryllium-like spectra. It is suggested that the upper levels (3d) are excited by quadrupole collisions from the ground 2s or 2s2levels.The intensity of the soft X-ray lines relative to the resonance lines in the 300 Å region seems to be more consistent with temperatures well above one million degrees than with temperatures as low as 700000°K, but the data are not adequate for a precise comparison. The relative intensity of the line emission from the various stages of silicon ionization may be interpreted as indicating that the ionization of silicon peaks in stages IX and X.The abundances of C, Mg, S, and Al relative to silicon do not seem to be greatly different from the chromospheric abundances reported by Pottasch or with the photospheric abundances.

The interaction of metastable helium atoms with alkali atoms

1987 ◽  
Vol 5 (1) ◽  
pp. 9-20 ◽  
Author(s):  
M. -W. Ruf ◽  
A. J. Yencha ◽  
H. Hotop
Keyword(s):  
Metastable Helium ◽  
Helium Atoms ◽  
Alkali Atoms

Resonance transitions 4d^105s–4d^95s5p in the Ag i sequence of In iii, Sn iv Sb v, and Te vi

1985 ◽  
Vol 2 (3) ◽  
pp. 426 ◽  
Author(s):  
V. Kaufman ◽  
Th. A. M. van Kleef ◽  
Y. Joshi ◽  
J. Sugar
Keyword(s):  
Resonance Transitions

Signal correlation in the tandem of a spin oscillator and microwave frequency discriminator with laser-pumped alkali atoms

2016 ◽  
Vol 42 (2) ◽  
pp. 186-190 ◽  
Author(s):  
A. A. Baranov ◽  
S. V. Ermak ◽  
E. A. Sagitov ◽  
R. V. Smolin ◽  
V. V. Semenov
Keyword(s):  
Microwave Frequency ◽  
Frequency Discriminator ◽  
Alkali Atoms ◽  
Spin Oscillator ◽  
Signal Correlation

Monoclinic and Hexagonal Nepheline Structures of (Na3/4/K1/4)AlGeO4

1998 ◽  
Vol 54 (3) ◽  
pp. 211-220 ◽  
Author(s):  
R. P. Hammond ◽  
J. Barbier
Keyword(s):  
Large Family ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Silicate Mineral ◽  
Tetrahedral Framework ◽  
Space Group ◽  
Cell Parameters ◽  
Monoclinic Form ◽  
Hexagonal Form ◽  
Alkali Atoms

Hexagonal (Na3/4K1/4)AlGeO4 crystallizes in the space group P63 with unit-cell parameters a = 10.164 (2), c = 8.540 (2) Å and Z = 8 [wR(F 2) = 0.066 for all 3060 independent reflections]. Monoclinic (Na3/4K1/4)AlGeO4 crystallizes in the space group P21 with unit-cell parameters a = 10.0477 (4), b = 8.5764 (4), c = 10.2118 (4) Å, β = 119.035 (1)° and Z = 8 [wR(F 2) = 0.120 for all 3194 independent reflections measured on a twinned crystal]. Both structures belong to the large family of stuffed tridymites, with the Al and Ge atoms occupying tetrahedral sites, and the alkali atoms occupying the cavities of the tetrahedral framework. Hexagonal (Na3/4K1/4)AlGeO4 is isostructural with the silicate mineral nepheline (Na3/4K1/4)AlSiO4, while monoclinic (Na3/4K1/4)AlGeO4 corresponds to a minor distortion of the nepheline structure. Chemical analysis by electron microprobe and structure determination of flux-grown single crystals indicate that the hexagonal form with the chemical formula (Na0.78K0.19)Al0.97Ge1.03O4 may be stabilized by an alkali deficiency similar to that found in hexagonal natural nephelines. In contrast, all alkali sites are fully occupied in the monoclinic form of composition (Na0.75K0.25)AlGeO4 and the lower symmetry eliminates the oxygen disorder present in the hexagonal form.

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