Observation of the Rotational Spectra of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow /><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>HeH</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:mrow></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><

Matsushima, Fusakazu; Oka, Takeshi; Takagi, Kojiro

doi:10.1103/physrevlett.78.1664

Cited by 54 publications

(56 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A significant contribution to the somewhat larger root-mean-weighted square for 4 HeH ϩ is the anomalously large residual for the J ϭ 1 4 0 microwave transition measured recently in Ref. (16).…”

Section: Resultsmentioning

confidence: 97%

Experimental Born–Oppenheimer Potential for theX1Σ+Ground State of HeH+: Comparison with theAb InitioPotential

Coxon

Hajigeorgiou

1999

Journal of Molecular Spectroscopy

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 97%

Experimental Born–Oppenheimer Potential for theX1Σ+Ground State of HeH+: Comparison with theAb InitioPotential

Coxon

Hajigeorgiou

1999

Journal of Molecular Spectroscopy

View full text Add to dashboard Cite

“…As a result, the spectrum of ammonia in many vibrational states has defied analysis to experimental accuracy. Figure 1 shows the inversion-vibration energy levels of 14 NH 3 up to 2000 cm −1 . Strong perturbations exist between the 2 = 2 and 4 = 1 states.…”

Section: Introductionmentioning

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…This means that under favourable circumstances it should be possible to observe both the HeH þ j ¼ 1-0 and j ¼ 2-1 rotational emission lines. Recent laboratory measurements gives these lines at wavelengths 149.137 and 74.7848 m respectively (Matsushima, Oka & Takagi 1997). Observation of both lines would give a much more secure detection than observation of a single transition ever could.…”

Section: O N C L U S I O N Smentioning

confidence: 99%

Calculated rotational and vibrational excitation rates for electron—HeH+ collisions

Rabadán¹,

Sarpal²,

Tennyson³

1998

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

A B S T R A C TMolecular R-matrix calculations are performed at a range of energies to give rotational and vibrational excitation and de-excitation cross-sections and, hence, rates for electron collisions with HeH þ up to electron temperatures of 20 000 K. Critical electron densities are also given. The rotational calculations include the Coulomb-Born completion of the cross-sections for high l values. Rates for the transition j ¼ 0 → 2, which have previously been assumed to be negligible, are found to be up to half those for j ¼ 0 → 1, raising the prospect of observing the HeH þ j ¼ 2 → 1 emission line at 74.8 m.

show abstract

Observation of the Rotational Spectra of4HeH+,<

Cited by 54 publications

References 22 publications

Experimental Born–Oppenheimer Potential for theX1Σ+Ground State of HeH+: Comparison with theAb InitioPotential

Experimental Born–Oppenheimer Potential for theX1Σ+Ground State of HeH+: Comparison with theAb InitioPotential

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

Calculated rotational and vibrational excitation rates for electron—HeH+ collisions

Contact Info

Product

Resources

About