The resonance escape factor for Voigt and Lorentz line profiles in atomic absorption measurements

Habib, A.A.M.; El-Gohary, Z.

doi:10.1016/s0022-4073(01)00128-5

Cited by 23 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resonance escape factor of the Lorentzian profile is larger than that of the Voigt profile, which is in agreement with the experimental result of Habib [8]. …”

supporting

confidence: 91%

“…(5) to calculate the normalized line profile and the maximum absorption coefficient for Voigt distribution. Drawin and Emard have established such a simple relation formula [8], i.e., for the Voigt line profile, the resonance escape factor L(τ 0 τ τ ) takes the form:…”

mentioning

confidence: 99%

“…This method, which was first given by Drawin and Emard, was used to calculate the optical escape factors for sodium and strontium [8].…”

mentioning

confidence: 99%

See 2 more Smart Citations

Theory of the resonance escape factors of plasma resonance lines basing on the exact Voigt profile

Zhang

2008

Front. Phys. China

View full text Add to dashboard Cite

In this paper, based on the exact Voigt profile we obtained, we derive the theory of resonance escape factors of plasma resonance lines, for both Lorentzian profile and Voigt profile. The oscillator strength, the number density of the absorbing atoms in the ground state, and the optical depth in the line center are discussed. As an example, the helium He I 1083.0 nm, lithium Li I 670.970 nm and carbon C I 111.74 nm are discussed for infrared, visible and ultraviolet regions. The results we calculated are in good agreement with the experimental results. These calculations will be significant in the theoretical analysis of plasma.The resonance escape factor is introduced to study the reabsorption of radiation in optical excitation in atom absorption measurements. The value of this factor, which approximately accounts for line self-absorption in a given gas, depends on the nature and geometry (diameter) of the gas. The escape factor also depends on the pressure and the profile of the spectral lines [1]. Under these conditions the value of the escape factor cannot be fixed. Moreover, it is a well-known fact that most laboratory gases are optically thin in most parts of the spectrum except for resonance radiation lines. The resonance radiation escape factor Λ r must appear as an additional parameter in arc gas. Computations and measurements of the optical escape factor representing the mean probability of photon escape have previously been developed [2−4].Generally, escape factors have been used in two similar situations to model the radiation transfer of spectral lines. In one situation, an escape factor multiplies the emission expected from optically thin plasma to allow for the effect of opacity on the emitted lines. In the other, an escape factor is a parameter that multiplies the radiative transition probability to allow for the effect of photo-excitation on population densities [5]. We calculated the resonance escape factor of helium plasma in the infrared region and obtained useful results [6].The Voigt profile function results from the convolution of the Gaussian profile and the Lorentzian profile. This function is interesting because it appears in a wide range of fields in physics and chemistry. For example, in plasma physics it describes the dispersion relation, and similar aspects appear in astrophysics and in optical spectroscopy. In atomic spectral analysis, the observed atomic spectral emission line even under the highest resolution does not correspond to a monochromatic line, but rather may be considered as an intensity versus frequency distribution with an intensity maximum at a central frequency dropping off to zero intensity at some interval on either side. There are several factors that determine the broadening of spectral lines, including the natural line width, Doppler broadening, pressure broadening, Stark and Zeeman broadening, self-absorption and self-reversal effects in the source, and hyperfine structure and isotope

show abstract

“…The resonance escape factor of the Lorentzian profile is larger than that of the Voigt profile, which is in agreement with the experimental result of Habib [8]. …”

supporting

confidence: 91%

mentioning

confidence: 99%

See 1 more Smart Citation

Theory of the resonance escape factors of plasma resonance lines basing on the exact Voigt profile

Zhang

2008

Front. Phys. China

View full text Add to dashboard Cite

show abstract

“…[3], the pressure is 10 −4 Pa. Through calculation, the oscillator strengths, the Ladenburg cross-section and the number densities of the absorbing atoms in the ground state of the six Fe XVII resonance lines are shown in Table 2.…”

Section: ê ×ùðø× ò × ù×× óòmentioning

confidence: 99%

Calculation of the escape probabilities of Fe XVII resonance lines for the Voigt profile

Zhang

2008

Front. Phys. China

View full text Add to dashboard Cite

Using the Voigt profile we obtained, we calculate the escape probabilities of Fe XVII resonance lines at 15. 02, 13.28, 12.12, 11.13, 11.02 and 10.12Å for optically thick plasma, both for slab and cylindrical geometry. The oscillator strength, the number density of the absorbing atoms in the ground state, and the optical depth in the line center are discussed in this calculation. Results show that the escape probabilities for the slab geometry are larger than that for the cylindrical geometry. This calculation is useful for the study of the Fe XVII resonance lines.

show abstract

“…In thermal plasmas, self-absorption has been known to occur and a number of studies of the phenomena based on the escape factor method have been published by Gleizes et al [23][24][25]. The same method has been applied in atomic absorption measurements [26]. Hannachi et al [27] applied the escape factor method in order to study the effect selfabsorption on measured intensity in the laser-induced plasma.…”

Section: Introductionmentioning

confidence: 99%

The resonance escape factor for Voigt and Lorentz line profiles in atomic absorption measurements

Cited by 23 publications

References 9 publications

Theory of the resonance escape factors of plasma resonance lines basing on the exact Voigt profile

Theory of the resonance escape factors of plasma resonance lines basing on the exact Voigt profile

Calculation of the escape probabilities of Fe XVII resonance lines for the Voigt profile

Calculation of the mean probability of photon capture for vacuum UV line emission of fluorine in the case of a thermal plasma mixture

Contact Info

Product

Resources

About