Absolute Intensity of the NH3 ν2 Band

Fabian, Mike; Yamada, Kōichi

doi:10.1006/jmsp.1999.7937

Cited by 27 publications

(7 citation statements)

References 15 publications

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“…62,[65][66][67] The predicted intensities for the regular ⌬K = 0 lines are found to agree well with the experimental results, with an overall rms difference of ϳ5%. The predicted intensities for low-J ⌬K = 3 transitions seemed reasonable ͑see Fig.…”

Section: Resultssupporting

confidence: 76%

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Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2=1 states of ammonia

Pearson

Drouin

et al. 2010

The Journal of Chemical Physics

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Complete and reliable knowledge of the ammonia spectrum is needed to enable the analysis and interpretation of astrophysical and planetary observations. Ammonia has been observed in the interstellar medium up to J=18 and more highly excited transitions are expected to appear in hot exoplanets and brown dwarfs. As a result, there is considerable interest in observing and assigning the high J (rovibrational) spectrum. In this work, numerous spectroscopic techniques were employed to study its high J transitions in the ground and ν2=1 states. Measurements were carried out using a frequency multiplied submillimeter spectrometer at Jet Propulsion Laboratory (JPL), a tunable far-infrared spectrometer at University of Toyama, and a high-resolution Bruker IFS 125 Fourier transform spectrometer (FTS) at Synchrotron SOLEIL. Highly excited ammonia was created with a radiofrequency discharge and a dc discharge, which allowed assignments of transitions with J up to 35. One hundred and seventy seven ground state and ν2=1 inversion transitions were observed with microwave accuracy in the 0.3–4.7 THz region. Of these, 125 were observed for the first time, including 26 ΔK=3 transitions. Over 2000 far-infrared transitions were assigned to the ground state and ν2=1 inversion bands as well as the ν2 fundamental band. Of these, 1912 were assigned using the FTS data for the first time, including 222 ΔK=3 transitions. The accuracy of these measurements has been estimated to be 0.0003–0.0006 cm−1. A reduced root mean square error of 0.9 was obtained for a global fit of the ground and ν2=1 states, which includes the lines assigned in this work and all previously available microwave, terahertz, far-infrared, and mid-infrared data. The new measurements and predictions reported here will support the analyses of astronomical observations by high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA. The comprehensive experimental rovibrational energy levels reported here will permit further refinement of the potential energy surface to improve ammonia ab initio calculations and facilitate assignment of new high-resolution spectra of hot ammonia.

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Section: Resultssupporting

confidence: 76%

“…64 for the ground state and from Ref. 65 for the 2 fundamental band, which are the same as those used in a previous paper. 16 All possible transitions up to J = 35 were predicted.…”

Section: Resultsmentioning

confidence: 99%

Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2=1 states of ammonia

Pearson

Drouin

et al. 2010

The Journal of Chemical Physics

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“…However, we do not believe these represent a systematic vibrational dependence since there are similar discrepancies between [37] and the more accurate recent m 2 measurements in [15]. Moreover, Fabian et al later reported diode laser [38] and FTS [39] measurements in better agreement with ours, yielding AEc m (m 2 )/c m (m 1 )ae = 0.96(6) for selfbroadening for 14 corresponding lines. Baldacchini et al [40] have measured the temperature dependence of the foreign-gas broadening of the aqQ (9,9) transition in the m 2 band using a diode laser.…”

Section: Broadeningssupporting

confidence: 71%

Self- and foreign-gas-broadened lineshapes in the ν1 band of NH3

Марков

2004

Journal of Molecular Spectroscopy

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“…Some of the papers on ammonia spectra [32][33][34]36,38,39,51,55,57,66,71,78,81,90,94,97,101,108,117] report only (temperature-dependent) line intensity or lineshape data or treat the theory of the ammonia spectra [70,83,110,118,133,134,181]; therefore, they are not employed in a direct fashion in this study though they proved to be useful during the preliminary analysis of the measured transitions. Some of the papers contain unassigned transitions which were not used during the MARVEL analysis though attempts, described above, were made to add missing vibrational labels to assigned but partially labelled spectra.…”

Section: Experimental Data and Data Treatmentmentioning

confidence: 94%

MARVEL analysis of the measured high-resolution spectra of 14NH3

Derzi

Furtenbacher

Tennyson

et al. 2015

Journal of Quantitative Spectroscopy and Radiative Transfer

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a b s t r a c tAccurate, experimental rotational-vibrational energy levels and line positions, with associated labels and uncertainties, are reported for the ground electronic state of the symmetric-top 14 NH 3 molecule. All levels and lines are based on critically reviewed and validated high-resolution experimental spectra taken from 56 literature sources. The transition data are in the 0.7-17 000 cm À 1 region, with a large gap between 7000 and 15 000 cm À 1 . The MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm is used to determine the energy levels. Out of the 29 450 measured transitions 10 041 and 18 947 belong to ortho-and para-14 NH 3 , respectively. A careful analysis of the related experimental spectroscopic network (SN) allows 28 530 of the measured transitions to be validated, 18 178 of these are unique, while 462 transitions belong to floating components. Despite the large number of spectroscopic measurements published over the last 80 years, the transitions determine only 30 vibrational band origins of 14 NH 3 , 8 for ortho-and 22 for para-14 NH 3 . The highest J value, where J stands for the rotational quantum number, for which an energy level is validated is 31. The number of experimental-quality ortho-and para-14 NH 3 rovibrational energy levels is 1724 and 3237, respectively. The MARVEL energy levels are checked against ones in the BYTe firstprinciples database, determined previously. The lists of validated lines and levels for 14 NH 3 are deposited in the Supporting Information to this paper. Combination of the MARVEL energy levels with first-principles absorption intensities yields a huge number of experimental-quality rovibrational lines, which should prove to be useful for the understanding of future complex high-resolution spectroscopy on 14 NH 3 ; these lines are also deposited in the Supporting Information to this paper.

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Absolute Intensity of the NH3 ν2 Band

Cited by 27 publications

References 15 publications

Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2=1 states of ammonia

Submillimeter-wave and far-infrared spectroscopy of high-J transitions of the ground and ν2=1 states of ammonia

Self- and foreign-gas-broadened lineshapes in the ν1 band of NH3

MARVEL analysis of the measured high-resolution spectra of 14NH3

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