Improved Fits for the Vibrational and Rotational Constants of Many States of Nitrogen and Oxygen

Laher, Russ R.; Gilmore, Forrest R.

doi:10.21236/ada229996

Cited by 9 publications

(13 citation statements)

References 16 publications

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“…This is consistent with the theoretical predictions of Dahl and Oddershede [] and the experimental upper limit of 80 μs determined by Holland []. The spectroscopic data of Laher and Gilmore [], Gilmore et al [], and Laher [] suggest lifetimes near 58–61 μs for v ′ = 0–3 (with additional v ′‐levels tabulated). Kedzierski and McConkey [, ] also just published work on N 2 that included an estimate of the LBH lifetime of ~75 μs; their measurement was capable of including some undetermined portion of “slow” cascade.…”

Section: Introductionsupporting

confidence: 89%

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade

et al. 2017

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We have measured the 100 eV emission cross section of the optically forbidden Lyman‐Birge‐Hopfield (LBH) band system (a1Πg → X1Σ+g) of N2 by electron‐impact‐induced fluorescence. Using a large (1.5 m diameter) vacuum chamber housing an electron gun system and the Mars Atmosphere and Volatile EvolutioN mission Imaging Ultraviolet Spectrograph optical engineering model, we have obtained calibrated spectral measurements of the LBH band system from 115 to 175 nm over a range of lines of sight to capture all of the optical emissions. These measurements represent the first experiment to directly isolate in the laboratory single‐scattering electron‐impact‐induced fluorescence from both direct excitation of the a1Πg state and cascading contributions to the a1Πg state (a′1Σ−u and w1Δu → a1Πg → X1Σ+g). The determination of the total LBH emission cross section is accomplished by measuring the entire cylindrical glow pattern of the metastable emission from electron impact by imaging lines of sight that measure the glow intensity from zero to ~400 mm radial distance and calculating the ratio of the integrated intensity from the LBH glow pattern to that of a simultaneously observed optically allowed transition with a well‐established cross section: Ni 120.0 nm. The “direct” emission cross section of the a1Πg state at 100 eV was determined to be σemdir = (6.41 ± 1.3) × 10−18 cm2. An important observation from the glow pattern behavior is that the total (direct + cascading) emission cross section is pressure dependent due to collision‐induced cascade transitions between close‐lying electronic states.

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Section: Introductionsupporting

confidence: 89%

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade

et al. 2017

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“…The vibrational energy E v is calculated according to Herzberg [1950] while the rotational energy E r,Ω for a given vibrational level v is determined by Fox and Hać [2009] where the coefficient B v reads as described by Laher and Gilmore [1991]. The coefficients ω e , ω e x e , B e , α e , γ e , and δ e appearing in –, are taken from Laher and Gilmore [1991] for the X 2 Π g state of the O 2 + ion.…”

Section: Hot O Atom Modelingmentioning

confidence: 99%

Venus' atomic hot oxygen environment

et al. 2010

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We present a Monte Carlo study of the atomic hot oxygen corona of Venus. In this model we consider elastic, inelastic, and quenching collisions between the traced hot particle and the ambient neutral atmosphere as well as differential cross sections to determine the scattering angle in the collisions. We also include rotational and vibrational excitation energies for the calculation of the initial energy of the produced hot oxygen atoms. Our results indicate that the differential cross sections and the fraction between elastic, inelastic, and quenching collisions are the most sensitive parameters which effect the corona density. We found that the hot O densities inferred from PVO observations can only be reproduced during high solar activity based on a forward scattering model but without inelastic and quenching collisions. The corona densities for low solar activity (VEX solar conditions) are about a factor of 2–3 smaller than for high solar activity.

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“…Benchmark candidates for µ variation measurement. The upper vibrational states n that maximize the absolute sensitivities are calculated from molecular constants [51], and achievable precision for zero dead time, C = 0.6, an averaging time T = 1 day, and a coherence time of 6 s [52]. Ω/(2π) and S/(2π) are in units of THz.…”

Section: Homonuclear Molecule Benchmarksmentioning

confidence: 99%

Optical Pumping of TeH+: Implications for Search for Varying mp/me

Stollenwerk¹,

Kokish²,

Oliveira-Filho³

et al. 2018

Preprint

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Molecular overtone transitions provide optical frequency transitions sensitive to variation in the proton-to-electron mass ratio (μ = mp/me). However, robust molecular state preparation presents a challenge critical for achieving high precision. Here, we characterize infrared and optical-frequency broadband laser cooling schemes for TeH+, a species with multiple electronic transitions amenable to sustained laser control. Using rate equations to simulate laser cooling population dynamics, we estimate the fractional sensitivity to μ attainable using TeH+. We find that laser cooling of TeH+ can lead to significant improvements on current μ variation limits.

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Improved Fits for the Vibrational and Rotational Constants of Many States of Nitrogen and Oxygen

Cited by 9 publications

References 16 publications

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade

Venus' atomic hot oxygen environment

Optical Pumping of TeH<sup>+</sup>: Implications for Search for Varying <em>m<sub>p</sub></em>/<em>m<sub>e</sub></em>

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Improved Fits for the Vibrational and Rotational Constants of Many States of Nitrogen and Oxygen

Cited by 9 publications

References 16 publications

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N2: Direct excitation and cascade

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N2: Direct excitation and cascade

Venus' atomic hot oxygen environment

Optical Pumping of TeH<sup>+</sup>: Implications for Search for Varying <em>m<sub>p</sub></em>/<em>m<sub>e</sub></em>

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Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade

Electron impact study of the 100 eV emission cross section and lifetime of the Lyman‐Birge‐Hopfield band system of N₂: Direct excitation and cascade