Absolute cross sections for simultaneous ionization and excitation of N<sub>2</sub>by electron impact

McConkey, J W; Latimer, I D

doi:10.1088/0370-1328/86/3/304

Cited by 41 publications

(7 citation statements)

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“… 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. It should be pointed out that anomalous threshold behavior in the cross section figure of McConkey et al [1967] was attributed to a graphic drawing error.…”

Section: Discussionmentioning

confidence: 99%

“…The B 2 Σ u + state, having a lifetime of 60 ∼ 80 ns, has been extensively measured. McConkey and Latimer [1965] measured excitation functions of the (0,0), (0,1) and (0,2) bands of B 2 Σ u + − X 2 Σ g + from threshold to 300 eV and obtained absolute emission cross sections by reference to the helium emission cross section. Subsequently, McConkey et al [1967] extended the measurement to 2000 eV using both standard quartz iodine and tungsten lamps.…”

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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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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“…The uncertainty in the colour temperature results in a 2 7 % error in the calibration curve. The relative calibration curve is then put on an absolute scale by utilizing the well-established cross sections for the N: 3914 A emission (10,11) and the visible He lines resulting from the excitation of the n ' S levels (12). We estimate an accuracy of 10% for the absolute calibration of the detection system based on the combined uncertainties in the colour temperature of the quartz-iodine lamp and in the benchmark cross sections.…”

Section: Culibrutiotz Of the Detectiotz Systemmentioning

confidence: 99%

“…by electron impact, play an important role in the physics of the plasma torus around Jupiter. The Voyager fly-by missions to Jupiter have revealed intense emissions from ionized sulphur and oxygen species with a peak emission intensity at a distance from the planet that coincides with the orbital radius of Jupiter's satellite 10. It has been suggested (1,2) that the breakup of SO?, which is shot into orbit from active volcanoes on 10 and dissociated and excited by photon and electron impact, is the most likely source of these emissions.…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet and visible fluorescence produced by controlled electron impact on SO₂

Miller¹,

Becker²

1987

Can. J. Phys.

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The emission spectrum in the ultraviolet and visible region of the optical spectrum (2000–8000 Å) produced by electron impact on SO2 has been studied under single-collision conditions. Two major features have been observed: the A3Π → X3Σ− system of the SO fragment (2400–2650 Å) and a broad, unstructured emission extending from 2500 to 4600 Å, which has been identified as arising from the excitation–de-excitation of the SO2 molecule. Absolute emission cross sections for the SO system have been measured for incident electron energies from threshold to 500 eV, and a value of 5.2 × 10−18 cm2 has been found at 100 eV with an uncertainty of approximately ± 18%. The maximum in the emission cross section is at 30 eV (6.5 × 10−18 cm2). The measured threshold of 11.5 eV is about 1 eV above the minimum energy required for partial fragmentation of SO2 into SO (A3Π) and a ground-state oxygen atom, indicating that very little translational kinetic energy is carried away by the dissociation fragments in the near-threshold region. A complex excitation–de-excitation scheme involving three different excited states of the SO2 molecule, e.g., the 8a1 → 3b1, 1.3B1 states and the 5b2 → 3b11A2 state, produces the broad 2500–4600 Å emission feature. At 100 eV, an emission cross section of 12.2 × 10−18 cm2 has been measured for the SO2 system. Several O1 and S1 emission lines have also been identified, yet they are found to be extremely weak with estimated emission cross sections smaller than 10−21 cm2 at 100 eV impact energy.

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“…When the 0, integration in Eq. (1) is performed, the result is N (Qn, ) AX = t(X) dp dit dQ f 0 lit X f d 3 r'( T + U cos 2 0,) g (r', p, 6,, X) (N/hc) AX, (3) where g(r', p, 6p, N) 9 7rp 4 sinO,,e(r ', p, N) with T 1 + n 2 2 and U 1 -3n 5 2 . The expression for Nm( Xs N)AX is also given by Eq.…”

Section: Angular Distribution Of the Radiation And The Polarization Fmentioning

confidence: 99%

Systematic Errors in Emission Cross Sections Arising in the Analysis of Laboratory Beam Measurements

et al. 1969

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A technique for obtaining emission cross sections in laboratory beam studies is presented, including effects on the cross section due to polarization of the emitted light. Systematic analytical errors arising from optical problems are analyzed and evaluated for a typical spectral feature. The primary sources of error are shown to arise from the particular geometry used in the optical measurements, the variation of the calibrating light source over the bandwidth of the emission feature, and the variation of the responsivity of the optical system over the bandwidth.

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Absolute cross sections for simultaneous ionization and excitation of N₂by electron impact

Cited by 41 publications

References 5 publications

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

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

Ultraviolet and visible fluorescence produced by controlled electron impact on SO₂

Systematic Errors in Emission Cross Sections Arising in the Analysis of Laboratory Beam Measurements

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Absolute cross sections for simultaneous ionization and excitation of N2by electron impact

Cited by 41 publications

References 5 publications

Evaluation of electron impact excitation of N2 X 1Σg+(0) into the N2+ X 2Σg+(v), A 2Πu(v), and B 2Σu+(v) states

Evaluation of electron impact excitation of N2 X 1Σg+(0) into the N2+ X 2Σg+(v), A 2Πu(v), and B 2Σu+(v) states

Ultraviolet and visible fluorescence produced by controlled electron impact on SO2

Systematic Errors in Emission Cross Sections Arising in the Analysis of Laboratory Beam Measurements

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Absolute cross sections for simultaneous ionization and excitation of N₂by electron impact

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

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

Ultraviolet and visible fluorescence produced by controlled electron impact on SO₂