A Densitometer Unit Uniquely Suited to Extracting Transient Molecular Absorption Bands from Spectrographic Records of Flash Photolysis Experiments

1970 ◽  
Vol 41 (11) ◽  
pp. 1584-1587
Author(s):  
J. S. Humphrey ◽  
J. H. Fielding
Keyword(s):  
Flash Photolysis ◽  
Molecular Absorption ◽  
Absorption Bands

Polarimetric Observations of Red Variables: A Study of Gas and Particle Interactions

1979 ◽  
Vol 46 ◽  
pp. 386-408 ◽  
Author(s):  
G. V. Coyne ◽  
I. S. McLean
Keyword(s):  
Wavelength Dependence ◽  
Stellar Atmosphere ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Absorption And Emission ◽  
Mira Variables ◽  
Stellar Photosphere ◽  
Regular Variable ◽  
Red Supergiants ◽  
Balmer Lines

AbstractIn recent years the wavelength, dependence of the polarization in a number of Mira variables, semi-regular variables and red supergiants has been measured with resolutions between 0.3 and 300 A over the range 3300 to 11000 A. Variations are seen across molecular absorption bands, especially TiO bands, and across atomic absorption and emission lines, especially the Balmer lines. In most cases one can ignore or it is possible to eliminate the effects due to interstellar polarization, so that one can study the polarization mechanisms operating in the stellar atmosphere and environment. The stars Omicron Ceti. (Mira), V CVn (semi-regular variable) and Mu Cephei (M2 la), in addition to other stars similar to them, will be discussed in some detail.Models to explain the observed polarization consider that the continuum flux is polarized either by electron, molecular and/or grain scattering or by temperature variations and/or geometrical asymmetries over the stellar photosphere. This polarized radiation is affected by atomic and molecular absorption and emission processes at various geometric depths in the stellar atmosphere and envelope. High resolution spectropolarimetry promises, therefore, to be a power-rul tool for studying stratification effects in these stars.

scholarly journals Surveys for Carbon Stars in External Galaxies

2000 ◽  
Vol 177 ◽  
pp. 51-58
Author(s):  
Marc Azzopardi
Keyword(s):  
Local Group ◽  
Galactic Halo ◽  
Magellanic Clouds ◽  
Carbon Stars ◽  
Molecular Absorption ◽  
Absorption Bands ◽  
Distant Galaxies ◽  
External Galaxies ◽  
Dwarf Spheroidals

Prominent molecular absorption bands in the spectra of carbon stars make their detection possible, even in relatively distant external galaxies. Although extensive surveys for carbon stars have been carried out mainly in the Magellanic Clouds and the dwarf spheroidals in the Galactic halo, more distant galaxies in the Local Group and beyond have been successfully searched for this kind of object.

The A2Πi–X2Πi absorption spectrum of BrO

1981 ◽  
Vol 59 (12) ◽  
pp. 1908-1916 ◽  
Author(s):  
M. Barnett ◽  
E. A. Cohen ◽  
D. A. Ramsay
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Ground State ◽  
Flash Photolysis ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Numbering Scheme ◽  
Ozonized Oxygen ◽  
Good Agreement

Absorption spectra of isotopically enriched 81Br16O and of normal BrO have been obtained by the flash photolysis of mixtures of bromine and ozonized oxygen. Rotational analyses are given for the 7–0, 12–0, 18–0, 19–0, 20–0, 21–0, 7–1, and 20–1 A2Π3/2–X2Π3/2 sub-bands of 81Br16O. The value for [Formula: see text] is found to be 722.1 ± 1.1 cm−1 in good agreement with the value calculated from microwave constants. Several additional bands have been found at the long wavelength end of the spectrum, necessitating a revision of the vibrational numbering scheme for both the emission and absorption bands. "Hot" bands up to ν″ = 6 have been observed in the absorption spectrum for the 2Π3/2 component of the ground state but no bands have yet been identified from the 2Π1/2 component.

ABSORPTION SPECTRA OF C3 AND C3H2 FROM THE FLASH PHOTOLYSIS OF DIAZOPROPYNE

1967 ◽  
Vol 45 (12) ◽  
pp. 4103-4111 ◽  
Author(s):  
A. J. Merer
Keyword(s):  
Absorption Spectrum ◽  
Free Radical ◽  
Ground State ◽  
Time Delays ◽  
Flash Photolysis ◽  
State Level ◽  
Vibrational Structure ◽  
Absorption Bands ◽  
Text Component ◽  
Ground State Level

The flash photolysis of diazopropyne (HC2∙CHN2) provides a particularly strong absorption spectrum of the free C3 radical. About 40 μs after the photolysis flash, the appearance of the [Formula: see text] (4 050 Å) system of C3 is similar to that obtained in the flash photolysis of diazomethane by Gausset, Herzberg, Lagerqvist, and Rosen, though much more intense. The intensity of the spectrum has permitted a study of the l-type doubling effect in the ground-state level 6ν2, of which the [Formula: see text] component has been found to lie at 458.2 cm−1. At shorter time delays [Formula: see text] the spectrum is complicated by bands arising from the levels ν1″ (1 224.5 cm−1) and 2ν1″ (2 436.0 cm−1).Below 3 700 Å the C3 spectrum is overlapped by absorption bands belonging to a new free radical, which has been identified from the intensity alternation in the rotational structure as the HCCCH radical. The vibrational structure of this system is exceptionally complex, and analysis has not been possible. The bands extend to about 3 100 Å, but are predissociated below 3 450 Å.

THE 2 700 Å BANDS OF THE N3 MOLECULE

1965 ◽  
Vol 43 (12) ◽  
pp. 2216-2221 ◽  
Author(s):  
A. E. Douglas ◽  
W. Jeremy Jones
Keyword(s):  
Fine Structure ◽  
High Resolution ◽  
Ground State ◽  
Flash Photolysis ◽  
Bond Distance ◽  
Absorption Bands

The 2 700 Å absorption bands found by Thrush in the flash photolysis of HN3 have been studied at high resolution. The rotational fine structure of the strongest band has been analyzed, and it has been shown that the bands arise from a [Formula: see text] transition of the N3 molecule. The bond distance in the ground state of N3 is found to be 1.181 Å.

scholarly journals The UV-visible absorption cross-sections of IONO<sub>2</sub>

2002 ◽  
Vol 2 (3) ◽  
pp. 227-234 ◽  
Author(s):  
J. C. Mössinger ◽  
D. M. Rowley ◽  
R. A. Cox
Keyword(s):  
Cross Sections ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Laser Flash ◽  
Absorption Bands ◽  
Visible Absorption ◽  
Time Resolved ◽  
Model Calculations ◽  
Solar Photolysis ◽  
Uv Visible

Abstract. The UV-visible absorption spectrum of gaseous IONO2 has been measured over the wavelength range 245--415 nm using the technique of laser photolysis with time-resolved UV-visible absorption spectroscopy. IONO2 was produced in situ in the gas phase by laser flash photolysis of NO2/CF3I/N2 mixtures. Post flash spectra were deconvolved to remove contributions to the observed absorption from other reactant and product species. The resulting spectrum attributed to IONO2 consists of several overlapping broad absorption bands. Assuming a quantum yield of unity for IONO2 photolysis, model calculations show that during sunlit hours at noon, 53° N, the first order solar photolysis rate coefficient (J value) for IONO2 is 4.0 x 10-2 s-1.

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