Verbreiterung und Verschiebung der Linien des C�siumserienendes durch Krypton

Füchtbauer, Chr; Hj, Reimers

doi:10.1007/bf01338432

Cited by 19 publications

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“…Four threeparameter Gaussian distribution functions have been hitherto proposed for the description of the shape of the UV-visible absorption continua: by Goodeve and Taylor, 45 by Fink and Goodeve, 46 by Johnston et al, 47 and by Maric et al 48 In these equations, the indices "max" and "med" denote the maximum and the median absorption, respectively, the latter being defined via ∫ 0 ν ˜med σ d ln(ν ˜) ) ∫ ν ˜med ∞ σ d ln(ν ˜) ) hB Einstein /2, where B Einstein is the Einstein absorption coefficient. 52,53 Note that the maximum and the median absorption coincide in eq 4 (i.e. ν ˜max ) ν ˜med and σ max ) σ med ).…”

Section: Description Of the Shape Of The Uv-visible Absorption Contin...mentioning

confidence: 95%

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Marić¹,

Burrows

1996

J. Phys. Chem.

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A number of mathematical descriptions of UV-visible absorption continua have been compared and contrasted by using some accurate measurements of the spectra of Cl 2 and BrCl recorded at 298 K. The ability of such descriptions to accurately represent the absorption, their use in deconvolution, interpolation, and extrapolation was a focus of interest. The best description of continua was found to be that obtained using semilogarithmic Gaussian distribution functions. In addition, a quantum-mechanical approach based on spectral moments was developed in a novel manner as a convenient means to analyze the fitted continua and to compute their temperature dependence. The so-called "reflection method", which has hitherto successfully been used for this purpose, was critically reanalyzed and its theoretical basis investigated. It was shown that, when correctly applied and interpreted, the reflection method yields a sufficiently accurate description of the temperature dependence of the UV-visible absorption continua for most applications in the fields of atmospheric and combustion chemistry. Furthermore, it is simpler and less computationally demanding than any other technique and is useful for obtaining the initial values needed for the iterative procedures inherent to the more accurate quantum-mechanical methods of spectral analysis. The semilogarithmic Gaussian distribution functions may also successfully be applied to the description of structured UV-visible spectra, provided that the detail of the structure is ignored.

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Section: Description Of the Shape Of The Uv-visible Absorption Contin...mentioning

confidence: 95%

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Marić¹,

Burrows

1996

J. Phys. Chem.

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“…Spectroscopic studies of the line broadening and shift of spectral series due to the interaction of highly excited atoms with neutral perturbers have been carried out by many groups during the past 47 years [1][2][3][4][5][6][7][8][9][10][11][12]. Because of convenience, the high vapour pressure of alkali metals, and the accessible spectral range, these experiments were solely concerned with the principal series lines of the alkali atoms.…”

Section: Introductionmentioning

confidence: 99%

Impact broadening and shift of RbnS andnD levels by noble gases

Weber

Niemax

1982

Z Physik A

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The impact broadening and shift of Rb nS and nD levels by the noble gases He, Ar and Xe have been measured by Doppler-free two-photon absorption from the 5S ground state in a thermionic diode up to high principal quantum numbers. The dependence of the broadening rates on n was found to be in qualitative agreement with theoretical data. While the broadening and shift rates of the Rb nS and nD levels due to collisions with He or Ar show only slightly different dependences along the series, the corresponding Rb-Xe data present strong differences indicating large contributions by inelastic collisions. For large n the broadening data were found to be independent of the principal quantum number and the angular momentum I. The measured constant values cannot be explained by taking only into account the polarisation contribution. It was found to be a factor of 1.5 to 2 larger than the corresponding theoretical predictions. The shift rates are n-and /-independent and in satisfactory agreement with theoretical values for large principal quantum numbers.

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“…, where B is the Einstein absorption coefficient. 14, 15 Lightfoot et al 1 showed that eq 1 adequately describes the shapes of the absorption continua of at least 15 RO 2 • radicals at room temperature, the only exceptions being HO 2 • and CH 3 O 2 • . The shape of the absorption continuum of HO 2 • reported by Crowley et al 16 could not be described via eq 1 in terms of a single band, whereas for CH 3 O 2 • the shape of each reviewed absorption continuum was found to be accurately described via eq 1, but the combined data scattered in such a manner that they could not be fitted.…”

Section: Assessment Of Previous Investigationsmentioning

confidence: 99%

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 2. The UV Spectra of RO₂^•Radicals

Marić¹,

Crowley

Burrows

1997

J. Phys. Chem. A

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The suitability of Gaussian distribution functions to describe the shape and temperature dependence of the UV absorption continua of peroxy radicals has been investigated. The ethylperoxy radical was used as a test case. Its 298 K absorption continuum was found to be best described by a semilogarithmic Gaussian distribution function. A linear Gaussian distribution function performed less well but still adequately described the continuous absorption. The temperature dependence of the ethylperoxy radical UV absorption continuum was also well predicted. Analogous results obtained for the methylperoxy radical support these conclusions. A theoretical comparison of the semilogarithmic and linear Gaussian distribution functions is given and a potential energy diagram of the ethylperoxy radical derived. The experimentally determined absorption cross sections of HO2 • have been reanalyzed. It is shown that either the measurements at short wavelengths are in error or an unidentified electronic transition of HO2 • exists.

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Verbreiterung und Verschiebung der Linien des C�siumserienendes durch Krypton

Abstract: Es wird die Verbreiterung der C~siumabsorptionslinien dureh Krypton yon 1 s --10 p bis I s --20 p gemessen, sowie die Verschiebung yon 1 s --

Cited by 19 publications

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Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Impact broadening and shift of RbnS andnD levels by noble gases

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 2. The UV Spectra of RO₂^•Radicals

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Verbreiterung und Verschiebung der Linien des C�siumserienendes durch Krypton

Abstract: Es wird die Verbreiterung der C~siumabsorptionslinien dureh Krypton yon 1 s --10 p bis I s --20 p gemessen, sowie die Verschiebung yon 1 s --

Cited by 19 publications

References 0 publications

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 1. Theory

Impact broadening and shift of RbnS andnD levels by noble gases

Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 2. The UV Spectra of RO2•Radicals

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Application of a Gaussian Distribution Function To Describe Molecular UV−Visible Absorption Continua. 2. The UV Spectra of RO₂^•Radicals