RELATIVISTIC CALCULATION OF TRANSITION PROBABILITIES FOR 557.7 nm AND 297.2 nm EMISSION LINES IN OXYGEN

Chantler, Christopher T.; Nguyen, T. V. B.; Lowe, John; Grant, I P

doi:10.1088/0004-637x/769/1/84

Cited by 10 publications

(5 citation statements)

References 37 publications

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“…Similarly, we find, for the forbidden E2 and M1 557.7-and 297.2-nm emission lines in oxygen [42], that dramatic improvements in convergence are possible and to an apparently arbitrary level subject to the completeness of the wave function. While it is inevitable that the form of the terms in the Hamiltonian and the methodology for implementation must limit the final accuracy, we do not yet see these limitations.…”

Section: Convergence Of the Breit Interaction In X-ray K α Forbisupporting

confidence: 63%

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

et al. 2014

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Much discussion in relativistic atomic physics and quantum optics has related to the interaction of gauge and perturbation of the Hamiltonian or Dirac operator. It has been commented that Lorentz and gauge independence requires different forms of the perturbation operator in shifting from one gauge to another. Equally, it has been commented that gauge convergence is not possible without different operator forms in different bases and without the operator being embedded within the self-consistent kernel. We explore the logic and self-consistency of these arguments, applied to the well-known Breit operator in an area of continuing discussion. We find that convergence is now possible to a remarkable degree including a Breit interaction operator in a form consistent with the gauge for length and velocity relativistic forms of the multipole operator, implemented at the configuration-interaction level. Excellent convergence is obtained for Breit interaction energies, interaction mixing coefficients, interaction transition probabilities and eigenenergies and transition probabilities in complex open shells (transition metal K α transitions and shake satellites), and forbidden transitions.

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Section: Convergence Of the Breit Interaction In X-ray K α Forbisupporting

confidence: 63%

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

et al. 2014

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“…This method was introduced in the GRASP2K manual [17]. It was used in the relativistic calculations for copper Ka [3,4], titanium Ka [18], for the 557.7 nm and 297.2 nm emission lines in oxygen [19] and for the transitions in O(I) and O(III) [20].…”

Section: Methods 1-default Ordering and Correct Angular Momenta Rangementioning

confidence: 99%

Characterization of the copperKβx-ray emission profile: anab initiomulti-configuration Dirac–Hartree–Fock approach with Bayesian constraints

Pham

Nguyen

Lowe

et al. 2016

J. Phys. B: At. Mol. Opt. Phys.

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We investigate the Kb characteristic radiation and the complex asymmetric structure of photoemission lines of copper, which provides a benchmark for theoretical and experimental studies of x-ray calibration series in transition metals. Ab initio multi-configuration Dirac-Hartree-Fock (MCDHF) calculations have been performed to study the complex open-shell many-electron problem in copper. The biorthogonalization technique permits determination of transition intensities and Einstein A coefficients. The results from our MCDHF calculations demonstrate excellent convergence in transition energies and intensities, as well as gauge invariance to 0.6%. Shake processes caused by single and double spectator vacancies from 3d, 3p, 3s and 4s subshells have also been investigated extensively. MCDHF has been performed to calculate energies and relative intensities of 3d, 3d 2 , 3p, 3s and 4s satellites, resulting in the total number of configuration states exceeding 100 000 and more than 1500 transition components. Our theoretical calculations of shake-off probabilities using the multi-configuration method in the sudden limit have a high degree of internal consistency with the best available experimental data for copper Kb. This supports the validity of relativistic atomic theory and sets a new benchmark even for poorly resolved characteristic spectra using current techniques of analysis.

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“…The branching ratio between the two transitions has been modeled from quantum mechanics ab initio principles (NIST; Kramida et al, 2018). A recent calculation by Chantler et al (2013) uses the multiconfiguration Dirac-Hartree-Fock method. A value of the R = A 555.7 nm /A 297.2 nm ratio equal to 16.7 was recommended by NIST, based on the ab initio calculations.…”

Section: Sources and Sinks Of O( 1 S) Atomsmentioning

confidence: 99%

“…Observations of both emissions in airglow and aurora have led to lower values, with a nightglow determination of R = 9.8 ± 1.0 by Slanger et al (2006) and an auroral value of R = 9.3 ± 0.5 by Gattinger et al (2009). A recent calculation by Chantler et al (2013) uses the multiconfiguration Dirac-Hartree-Fock method. Their calculations were made in both the length and velocity gauges so that their accuracy could be monitored by the gauge convergence.…”

Section: Sources and Sinks Of O( 1 S) Atomsmentioning

confidence: 99%

The O(¹S) 297.2‐nm Dayglow Emission: A Tracer of CO₂ Density Variations in the Martian Lower Thermosphere

et al. 2018

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The O(1S) metastable atoms can radiatively relax by emitting airglow at 557.7 and 297.2 nm. The latter one has been observed with the Imaging Ultraviolet Spectrograph onboard the Mars Atmosphere and Volatile Evolution Mars orbiter since 2014. Limb profiles of the 297.2‐nm dayglow have been collected near periapsis with a spatial resolution of 5 km or less. They show a double‐peak structure that was previously predicted but never observed during earlier Mars missions. The production of both 297.2‐nm layers is dominated by photodissociation of CO2. Their altitude and brightness is variable with season and latitude, reflecting changes in the total column of CO2 present in the lower thermosphere. Since the lower emission peak near 85 km is solely produced by photodissociation, its peak is an indicator of the unit optical depth pressure level and the overlying CO2 column density. Its intensity is directly controlled by the Lyman‐α solar flux reaching the Martian upper atmosphere. We take advantage of the Lyman‐α flux measurements of the solar Extreme Ultraviolet Monitor instrument onboard Mars Atmosphere and Volatile Evolution to model the observed OI 297.2‐nm limb profiles. For this, we combine photodissociation sources with chemical processes and photoelectron impact excitation. To determine the relative importance of the excitation processes, we apply the model to the atmospheric structure measured by the Viking 1 lander before applying it to a model atmosphere. We find very good agreement with the lower peak structure and intensity if the CO2 density provided by the Mars Climate Database is scaled down by a factor between 0.50 and 0.66. We also determine that the previously uncertain quantum yield for production of O(1S) atoms by photodissociation of CO2 at Lyman‐α wavelength is about 8%.

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RELATIVISTIC CALCULATION OF TRANSITION PROBABILITIES FOR 557.7 nm AND 297.2 nm EMISSION LINES IN OXYGEN

Cited by 10 publications

References 37 publications

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

Characterization of the copperKβx-ray emission profile: anab initiomulti-configuration Dirac–Hartree–Fock approach with Bayesian constraints

The O(¹S) 297.2‐nm Dayglow Emission: A Tracer of CO₂ Density Variations in the Martian Lower Thermosphere

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RELATIVISTIC CALCULATION OF TRANSITION PROBABILITIES FOR 557.7 nm AND 297.2 nm EMISSION LINES IN OXYGEN

Cited by 10 publications

References 37 publications

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

Convergence of the Breit interaction in self-consistent and configuration-interaction approaches

Characterization of the copperKβx-ray emission profile: anab initiomulti-configuration Dirac–Hartree–Fock approach with Bayesian constraints

The O(1S) 297.2‐nm Dayglow Emission: A Tracer of CO2 Density Variations in the Martian Lower Thermosphere

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The O(¹S) 297.2‐nm Dayglow Emission: A Tracer of CO₂ Density Variations in the Martian Lower Thermosphere