Sub-doppler spectroscopy of the ν2 band of NH3 using microwave modulation sidebands of CO2 laser lines

Magerl, Gottfried; Schupita, Walter; Frye, Joan M.; Kreiner, W. A.; Oka, Takeshi

doi:10.1016/0022-2852(84)90266-2

Cited by 69 publications

(31 citation statements)

References 38 publications

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“…The operator code for this interaction is 600VV in the SPFIT/ SPCAT programs A total of 4394 transitions were included in the current analysis, including 2166 transitions assigned in this study and 2228 transitions from previous microwave studies 16,[29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] and infrared studies. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] Each of the 4394 transitions was weighed by its experimental uncertainty.…”

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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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: 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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“…1.3). The theory of Lamb dips and crossover dips has been worked out by Oka and collaborators [15,16], and has been applied to the discussion of numerous spectra, particularly also to the H 12 CN data [2]. As an example for the occurrence of saturation dips we compare the traces of several line profiles of H 12 CN (see Fig.…”

Section: S U B -D O P P L E R M E a S U R E M E N T S : L A M B D I Pmentioning

confidence: 99%

High Resolution Spectroscopy of HCN Isotopomers: H¹³CN, HC¹⁵N, and H13C15N in the Ground and First Excited Bending Vibrational State

Fuchs

Brünken

Fuchs

et al. 2004

Zeitschrift Für Naturforschung A

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The eleven energetically lowest pure rotational transitions, J ← J − 1 (J = 1, 2,... ,11), of H 13 CN, H 13 C 15 N, and HC 15 N in the ground and first excited bending state were measured. By operating the Cologne Tetrahertz Wave Spectrometer up to 1 THz in the sub-Doppler mode, a transition frequency accuracy of a few kHz is achieved. These measurements were carried out at frequencies between 80 -950 GHz. In addition, some transitions of the three isotopomers with rotational quantum numbers J = 20, 21, 22, 23 have been measured in Doppler-limited resolution near 2 THz, using the frequency stabilized Cologne Sideband Spectrometer for Terahertz Applications (COSSTA). Furthermore, direct l-type transitions of H 13 CN in the first excited bending state with J up to 35 have been measured. These new data are of particular importance, since we discovered highly excited circumstellar H 12 CN recently. A global fit of the newly enlarged data set together with existing carefully screened ro-vibrational data yields molecular constants which are highly reliable and of great importance both for astrophysical observations and laboratory applications.

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“…We furthermore note that the accurate prediction of the intensity for the ghost transitions (see Ref. [25]) is essential for correctly reproducing the observed spectra. Figures 1 2 and 2 provide representative examples, clearly demonstrating that ghost transitions cannot be neglected for a proper analysis.…”

Section: Analysis Of the Spectramentioning

confidence: 88%

The hyperfine structure in the rotational spectra of D2O: Lamb-dip measurements and quantum-chemical calculations

et al. 2010

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Sub-doppler spectroscopy of the ν2 band of NH3 using microwave modulation sidebands of CO2 laser lines

Cited by 69 publications

References 38 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

High Resolution Spectroscopy of HCN Isotopomers: H¹³CN, HC¹⁵N, and H13C15N in the Ground and First Excited Bending Vibrational State

The hyperfine structure in the rotational spectra of D2O: Lamb-dip measurements and quantum-chemical calculations

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Sub-doppler spectroscopy of the ν2 band of NH3 using microwave modulation sidebands of CO2 laser lines

Cited by 69 publications

References 38 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

High Resolution Spectroscopy of HCN Isotopomers: H13CN, HC15N, and H13C15N in the Ground and First Excited Bending Vibrational State

The hyperfine structure in the rotational spectra of D2O: Lamb-dip measurements and quantum-chemical calculations

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High Resolution Spectroscopy of HCN Isotopomers: H¹³CN, HC¹⁵N, and H13C15N in the Ground and First Excited Bending Vibrational State