High-resolution Fourier transform spectroscopy of the Meinel system of OH

Aims. A flux-calibrated high-resolution spectrum of the airglow emission is a practical λ-calibration reference for astronomical spectral observations. It is also useful for constraining the molecular parameters of the OH molecule and the physical conditions in the upper mesosphere. Methods. We used the data collected during the first technical commissioning of the GIANO spectrograph at the Telescopio Nazionale Galileo (TNG). The high-resolution (R 50 000) spectrum simultaneously covers the 0.95-2.4 μm wavelength range. Relative flux calibration is achieved by the simultaneous observation of a spectrophotometric standard star. Results. We derived a list of improved positions and intensities of OH infrared lines. The list includes Λ-split doublets, many of which are spectrally resolved. Compared with previous works, the new results correct errors in the wavelengths of the Q-branch transitions. The relative fluxes of OH lines from different vibrational bands show remarkable deviations from theoretical predictions: the Δv = 3, 4 lines are a factor of 2 and 4 brighter than expected. We also found evidence of a significant fraction (1-4%) of OH molecules with a non-thermal population of high-J levels. Finally, we list wavelengths and fluxes of 153 lines not attributable to OH. Most of these can be associated with O 2 , while 37 lines in the H band are not identified. The O 2 and unidentified lines in the H band account for 5% of the total airglow flux in this band.

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“…The observed wavelengths agree with those expected by the most accurate molecular energy levels available in the literature (Abrams et al 1994).…”

Section: Discussionsupporting

confidence: 87%

“…The listed wavelengths are derived from the OH energy level positions of Abrams et al (1994). These are the most accurate molecular data available in the literature and yield line wavelengths with an rms accuracy of 0.0035 cm −1 , equivalent to 0.01 Å at 16 000 Å.…”

Section: Oh Wavelengths and Fluxesmentioning

confidence: 99%

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

Oliva

Origlia

Maiolino

et al. 2013

A&A

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“…It was recently pointed out by Cosby et al 33 and Colin et al 34 that the spectroscopic constants used to generate the energy levels in the calculations of Goldman et al are flawed at higher vibrational ͑v Ͼ 3͒ and rotational levels ͑J Ͼ 19/ 2͒, producing differences with experiment up to 0.14 cm −1 . Both authors performed an improved fit of existing spectroscopic data by Abrams et al 35 The main disadvantage of experimentally determined electric dipole moment functions is that the regions outside the range of experimentally probed internuclear distances are badly described. Thus, extrapolation to higher rovibrational levels, which probe larger and smaller interatomic distances, is hardly possible.…”

Section: Introductionmentioning

confidence: 99%

Theoretical transition probabilities for the OH Meinel system

Loo

Groenenboom

2007

The Journal of Chemical Physics

138

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The authors present a new potential energy curve, electric dipole moment function, and spin-orbit coupling function for OH in the X 2 ⌸ state, based on high-level ab initio calculations. These properties, combined with a spectroscopically parametrized lambda-type doubling Hamiltonian, are used to compute the Einstein A coefficients and photoabsorption cross sections for the OH Meinel transitions. The authors investigate the effect of spin-orbit coupling on the lifetimes of rovibrationally excited states. Comparing their results with earlier ab initio calculations, they conclude that their dipole moment and potential energy curve give the best agreement with experimental data to date. The results are made available via EPAPS Document No. E-JCPSAG-017709.

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“…We therefore measured a substantial number of OH lines in the wavelength range 5200-7680 Å in the sky spectra, whose laboratory wavelengths l 0 are well known (Abrams et al 1994) to find the deviation . Tables 2-9.…”

Section: Wavelength Measurements and Identificationsmentioning

confidence: 99%

The High‐Resolution Light‐polluted Night‐Sky Spectrum at Mount Hamilton, California

Slanger

Cosby

Osterbrock

et al. 2003

PUBL ASTRON SOC PAC

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ABSTRACT. Sky spectra were recorded over San Jose at the Lick Observatory over the 3800-9200 Å spectral range, with a spectral resolution of 45,000. Strong atomic lines were detected from Al i, Ar i, Hg i, K i, Li i, Na i, Ne i, Sc i, Sc ii, Th i, Th ii, and from O i and OH nightglow features. Spectra are contrasted for observations over San Jose (west), the zenith direction, and the eastern sky. When observing in the easterly direction, the emission intensity is still 20%-30% of that seen toward the west. For a natural and stable terrestrial nightglow line, O i l5577, the intensity is comparable in either direction. A variety of line shapes are observed, reflecting the outputs of the mélange of pollution sources. A total of 177 identified light-pollution lines were observed, of which more than half are due to Sc i and Sc ii. The Sc i lines show a systematic shift to longer wavelengths from the expected positions, amounting to an average of 25 mÅ . This is presumably a consequence of their origin, high-pressure metal halide lamps. By comparing the intensity of the strongest pollution lines and continuum (from Na) with the nightglow O i l5577 line, a figure of merit for the pollution line intensity is the equivalent of 4 kR for the atmospheric conditions and viewing geometry investigated.

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High-resolution Fourier transform spectroscopy of the Meinel system of OH

Cited by 92 publications

References 19 publications

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

A GIANO-TNG high-resolution infrared spectrum of the airglow emission

Theoretical transition probabilities for the OH Meinel system

The High‐Resolution Light‐polluted Night‐Sky Spectrum at Mount Hamilton, California

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