Molecular beam electric resonance study of formaldehyde, thioformaldehyde, and ketene

Fabricant, Barbara; Krieger, David; Muenter, J. S.

doi:10.1063/1.434988

Cited by 183 publications

(83 citation statements)

References 36 publications

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“…These parameters reproduce the ab initio dipole moment values of the µA 1 , µB 1 , and µB 2 components with rms errors of 0.0002 Debyes for each component. The equilibrium value of our dipole moment is 2.3778 D (at r e CO = 1.2033742Å, r e CH = 1.10377Å, θ e OCH = 121.844 • ), which can be compared to the experimental value of the ground vibrational state dipole moment of µ=2.3321(5) D measured by Fabricant et al (1977). The eigenvectors, obtained by diagonalization, are used in conjunction with the DMS to compute the required linestrengths (and from that the Einstein-A coefficients and absolute intensities) of transitions that satisfy the rotational selection rules…”

Section: Dipole Moment Surface and Intensitiesmentioning

confidence: 99%

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

Al-Refaie

Yachmenev

Tennyson

et al. 2015

Monthly Notices of the Royal Astronomical Society

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A computed line list for formaldehyde, H 2 12 C 16 O, applicable to temperatures up to T = 1500 K is presented. An empirical potential energy and ab initio dipole moment surfaces are used as the input to nuclear motion program TROVE. The resulting line list, referred to as AYTY, contains 10.3 million rotational-vibrational states and around 10 billion transition frequencies. Each transition includes associated Einstein-A coefficients and absolute transition intensities, for wavenumbers below 10 000 cm −1 and rotational excitations up to J = 70. Room-temperature spectra are compared with laboratory measurements and data currently available in the HITRAN database. These spectra show excellent agreement with experimental spectra and highlight the gaps and limitations of the HITRAN data. The full line list is available from the CDS database as well as at www.exomol.com.

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Section: Dipole Moment Surface and Intensitiesmentioning

confidence: 99%

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

Al-Refaie

Yachmenev

Tennyson

et al. 2015

Monthly Notices of the Royal Astronomical Society

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“…The molecular parameters determined from their work, which include one sextic-order centrifugal distortion parameter, allowed frequency predictions through the 300 GHz region with less than 500 kHz error. Five years later, Fabricant et al (1977) measured an improved dipole moment of 1.6491(4) D.…”

Section: à9mentioning

confidence: 99%

High‐Frequency Rotational Spectrum of Thioformaldehyde, H₂CS, in the Ground Vibrational State

Maeda

Medvedev

Winnewisser

et al. 2008

ASTROPHYS J SUPPL S

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Pure rotational transitions have been measured for the normal isotopologue of thioformaldehyde, H 12 2 C 32 S, in the ground vibrational state in the 110-370 GHz, 570-670 GHz, and 850-930 GHz frequency ranges. A global data set has been constructed consisting of prior microwave and millimeter-wave transitions, the submillimeter-wave and terahertz (THz) transitions reported here, and far-infrared data and ground state combination differences. The 783 different transition frequencies in the data set were fit to Watson's S-reduced Hamiltonian with 20 parameters, resulting in a dimensionless weighted root-mean-square deviation of 0.78. New frequency predictions have been made for astronomical observations based on the molecular parameters obtained in the present study.

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“…The rotational constants used to derive the line frequencies were taken from the CDMS Catalog 2 for H 2 CS (Maeda et al 2008) and H 2 13 CS. The H 2 CS dipole moment, μ = 1.6491D, is the one measured by Fabricant et al (1977). For H 2 C 34 S (ortho and para) and HDCS, the line parameters were fitted from all rotational lines reported by Minowa et al (1997) and the observed lines towards B1 dark cloud by Marcelino et al (2005).…”

Section: H 2 Csmentioning

confidence: 99%

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

Tercero

Cernicharo

Pardo

et al. 2010

A&A

155

250

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We perform a sensitive (line confusion limited), single-side band spectral survey towards Orion KL with the IRAM 30 m telescope, covering the following frequency ranges: 80−115.5 GHz, 130−178 GHz, and 197−281 GHz. We detect more than 14 400 spectral features of which 10 040 have been identified up to date and attributed to 43 different molecules, including 148 isotopologues and lines from vibrationally excited states. In this paper, we focus on the study of OCS, HCS + , H 2 CS, CS, CCS, C 3 S, and their isotopologues. In addition, we map the OCS J = 18−17 line and complete complementary observations of several OCS lines at selected positions around Orion IRc2 (the position selected for the survey). We report the first detection of OCS ν 2 = 1 and ν 3 = 1 vibrationally excited states in space and the first detection of C 3 S in warm clouds. Most of CCS, and almost all C 3 S, line emission arises from the hot core indicating an enhancement of their abundances in warm and dense gas. Column densities and isotopic ratios have been calculated using a large velocity gradient (LVG) excitation and radiative transfer code (for the low density gas components) and a local thermal equilibrium (LTE) code (appropriate for the warm and dense hot core component), which takes into account the different cloud components known to exist towards Orion KL, the extended ridge, compact ridge, plateau, and hot core. The vibrational temperature derived from OCS ν 2 = 1 and ν 3 = 1 levels is 210 K, similar to the gas kinetic temperature in the hot core. These OCS high energy levels are probably pumped by absorption of IR dust photons. We derive an upper limit to the OC 3 S, H 2 CCS, HNCS, HOCS + , and NCS column densities. Finally, we discuss the D/H abundance ratio and infer the following isotopic abundances: 12 C/ 13 C = 45 ± 20, 32 S/ 34 S = 20 ± 6, 32 S/ 33 S = 75 ± 29, and 16 O/ 18 O = 250 ± 135.

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Molecular beam electric resonance study of formaldehyde, thioformaldehyde, and ketene

Abstract: Articles you may be interested inA semiempirical theoretical study of the [2+2] cycloaddition between ketene and formaldehyde AIP Conf. Proc. 330, 222 (1995); 10.1063/1.47652 Molecular beam electric resonance study of the ground and excited states of cyanoacetylene

Cited by 183 publications

References 36 publications

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

High‐Frequency Rotational Spectrum of Thioformaldehyde, H₂CS, in the Ground Vibrational State

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

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Molecular beam electric resonance study of formaldehyde, thioformaldehyde, and ketene

Abstract: Articles you may be interested inA semiempirical theoretical study of the [2+2] cycloaddition between ketene and formaldehyde AIP Conf. Proc. 330, 222 (1995); 10.1063/1.47652 Molecular beam electric resonance study of the ground and excited states of cyanoacetylene

Cited by 183 publications

References 36 publications

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

ExoMol line lists – VIII. A variationally computed line list for hot formaldehyde

High‐Frequency Rotational Spectrum of Thioformaldehyde, H2CS, in the Ground Vibrational State

A line confusion limited millimeter survey of Orion KL I. Sulfur carbon chains

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Product

Resources

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High‐Frequency Rotational Spectrum of Thioformaldehyde, H₂CS, in the Ground Vibrational State