Absolute Cross Sections for Simultaneous Ionization and Excitation of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>by Electron Impact

Srivastava, B. N.; Mirza, Ishaq Muhammad

doi:10.1103/physrev.168.86

Cited by 40 publications

(10 citation statements)

References 7 publications

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“…The present cross section, obtained by setting f XB to the photoionization oscillator strength while retaining the Borst and Zipf [1970] shape, is very close to that of McConkey et al [1971] and the average value. Cross sections reported by Srivastava and Mirza [1968a] and Shaw and Campos [1983] are the peak values of the (0,0) band emission, and are treated as if they were 100 eV values since the maximum occurs near 100 eV. The difference between Doering and Yang [1996] and Doering and Yang [1997] is presumably due to a small difference in branching ratios and the use of different total nondissociative ionization cross sections.…”

Section: Discussionmentioning

confidence: 99%

“…All other measurements employed the optical detection method with different methods of calibration. Aarts et al [1968], Aarts [1970], and Shaw and Campos [1983] utilized the helium emission cross section as a secondary standard while Srivastava and Mirza [1968a, 1968b], and Borst and Zipf [1970] used a standard tungsten lamp for absolute calibration. McConkey and Latimer [1965] and McConkey et al [1967, 1971] used helium, standard iodine lamps, as well as standard tungsten lamps.…”

Section: Discussionmentioning

confidence: 99%

“…McConkey and Latimer [1965] 14.7 Srivastava and Mirza [1968a] 16.8 ± 3.7 a Aarts et al [1968] 21.2 ± 2.1 Aarts [1970] 17.8 ± 1.8 b Stanton and St. John [1969] 15.6 ± 2.8 c Borst and Zipf [1970] 17.4 ± 1.7 McConkey et al [1971] 15.0 ± 0.9 d Skubenich and Zapesochnyy [1981] 16.7 Shaw and Campos [1983] 15.4 ± 1.5 a Doering and Yang [1996] 12.5 ± 2.5 Doering and Yang [1997] 12. Table 1).…”

Section: References Cross Sectionmentioning

confidence: 99%

“… Borst and Zipf [1970] also measured the absolute (0,0) band emission cross section using a standard tungsten lamp. Other emission cross section measurements of the B 2 Σ u + − X 2 Σ g + band include Aarts et al [1968], Srivastava and Mirza [1968a, 1968b, 1969], Stanton and St. John [1969], and Shaw and Campos [1983]. The A 2 Π u state, having a lifetime of several μs, is more difficult to measure.…”

Section: Introductionmentioning

confidence: 99%

“…The A 2 Π u state, having a lifetime of several μs, is more difficult to measure. Experimental investigations of the A 2 Π u − X 2 Σ g + emission cross section have been reported by Srivastava and Mirza [1968a], Stanton and St. John [1969], Shemansky and Broadfoot [1971a, 1971b], Holland and Maier [1972, 1973], Pendleton and Weaver [1973], Skubenich and Zapesochnyy [1981], and Piper et al [1986]. Other electron impact studies of nondissociative ionization of N 2 include Van de Runstraat et al [1974] for the C 2 Σ u + state, and Fons et al [1994] for the D 2 Π g state.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of electron impact excitation of N₂ X ¹Σ_g⁺(0) into the N₂⁺ X ²Σ_g⁺(v), A ²Π_u(v), and B ²Σ_u⁺(v) states

Shemansky

Liu

2005

J. Geophys. Res.

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Published experimental integrated electric dipole photoionization oscillator strengths (fij) have been applied to the determination of absolute electron impact excitation cross sections of the N2 X 1Σg+(0) state into the N2+ X 2Σg+(v), A 2Πu(v), and B 2Σu+(v) states. The required relative electron impact cross section shape functions from threshold to energy values, limited by the imposition of relativistic effects at the high end, are established in this work by extracting accurate analytic functions from a critical review of extensive published experimental results. The cross sections examined here are important benchmarks used in establishing absolute values for critical rate processes in aeronomy. The determination of the absolute cross sections using the derived fij is accomplished through the physical relationship to a modified Born approximation analytic function that defines the electron impact shape functions. The zero order term of the analytic function is established in value relative to the remaining terms through shape analysis of the experimental electron impact results. The value of fij fixes the absolute value of the zero order term, determining the cross sections over the entire electron impact energy range. It is argued that this methodology is the most accurate approach at this time because of the existence of the intrinsically more accurate photometrically dermined fij. The critical quantities in atmospheric process applications are the branching ratios of excitation into the N2+ X 2Σg+, A 2Πu, and B 2Σu+ states. The N2+ (X 2Σg+, A 2Πu, B 2Σu+) partitioning within the total ionization cross section has been a source of disagreement in the literature, in spite of the fact that substantial effort has been expended in establishing acceptably accurate values. The present work establishes accurate cross sections for these states over the entire practical energy range required for research in atmospheric N2 physical chemistry. The accuracy of the results obtained here are verified by consistency with the most reliably established past experimental electron impact cross sections, in agreement with the independently established total N2+ cross section. We provide analytic collision strengths for the vibrational levels of the N2+ X 2Σg+, A 2Πu, and B 2Σu+ states, allowing establishment of rate coefficients for the system, at an estimated error ≤±8%.

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