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Title: Laboratory Study of the Cameron Bands, the First Negative Bands, and Fourth Positive Bands in the Middle Ultraviolet 180–280 nm by Electron Impact upon CO
We have analyzed medium-resolution (FWHM = 1.2 nm) Middle UltraViolet (MUV; 180–280 nm) laboratory emission spectra of CO excited by electron impact at 15, 20, 40, 50, and 100 eV under single-scattering conditions at 300 K. The MUV emission spectra at 100 eV contain the Cameron Bands (CB) CO(a 3Π → X 1Σ+), the Fourth Positive Group (4PG) CO(A 1Π → X 1Σ+), and the First Negative Group (1NG) CO+(B 2Σ+ → X 2Σ) from direct excitation and cascading-induced emission of an optically-thin CO gas. We have determined vibrational intensities and emission cross sections for these systems, which are important for modeling UV observations of the atmospheres of Mars and Venus. We have also measured the CB ‘glow’ profile about the electron beam of the long-lived CO (a 3Π) state and determined its average metastable lifetime of approximately 3 ± 1 ms. Optically-allowed cascading from a host of triplet states has been found to be the dominant excitation process contributing to the CB emission cross section at 15 eV, most strongly by the d 3Δ and a' 3Σ+ electronic states. We normalized the CB emission cross section at 15 eV electron impact energy by Multi-Linear Regression (MLR) analysis to the more » blended 15 eV MUV spectrum over the spectral range of 180–280 nm, based on the 4PG emission cross section at 15 eV that we have previously measured (Ajello et al., 2019). We find the Cameron band total emission cross section at 15 eV to be (7.65 ± 2.68) × 10−17 cm2. « less
Authors:
Award ID(s):
1657686
Publication Date:
NSF-PAR ID:
10286384
Journal Name:
Journal of Geological Research
Volume:
126
Page Range or eLocation-ID:
15
ISSN:
1687-8833
Sponsoring Org:
National Science Foundation
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