A Search for the 1
            <sub>10</sub>
            ← 1
            <sub>11</sub>
            Transition of Interstellar Thioformaldehyde

Evans, Neal J.; Townes, C. H.; Weaver, Harold F.; Williams, D. R.

doi:10.1126/science.169.3946.680

Cited by 17 publications

(9 citation statements)

References 4 publications

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“…Thecorrelation between the Criegee reaction barrier and the nature of heteroatom in H 2 Xm ay have important implications for atmospheric and synthetic organic chemistry. Forexample,thioformaldehyde (HCHS) has been detected in dark clouds,t he interstellar clouds [18][19][20] and circumsteller envelope around an asymptotic giant branch star. [21] Fewlines of HCHS have also been identified in the Orion KL nebula [22] and in the atmosphere of the comet Hale-Bopp.…”

Section: Angewandte Chemiementioning

confidence: 99%

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

Kumar

Francisco

2016

Angew Chem Int Ed

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High-level quantum-chemical calculations have been performed to understand the key reactivity determinants of bimolecular reactions of Criegee intermediates and H X (X=O, S, Se, and Te). Criegee intermediates are implicated as key intermediates in atmospheric, synthetic organic, and enzymatic chemistry. Generally, it is believed that the nature and location of substituents at the carbon of the Criegee intermediate play a key role in determing the reactivity. However, the present work suggests that it is not only the substitution of the Criegee intermediate, but the nature of the heteroatom in H X that also plays a crucial role in determining the reactivity of the interaction between the Criegee intermediate and H X. The barriers for the reactions of Criegee intermediates and H X satisfy an inverse correlation with the bond strength of X-H in H X, and a direct correlation with the first pK of H X. This heteroatom tuning causes a substantial barrier lowering of 8-11 kcal mol in the Criegee reaction barrier in going from H O to H Te. An important implication of these results is that the reaction of the Criegee intermediate and H S could be a source of thioaldehydes, which are important in plantery atmospheres and synthetic organic chemistry. By performing the reaction of Criegee intermediates and H S under water or acid catalysis, thioladehydes could be detected in a hydrogen-bonded complexed state, which is significantly more stable than their uncomplexed form. As a result, simpler aliphatic thioaldehydes could be selectively synthesized in the laboratory, which, otherwise, has been a significant synthetic challenge because of their ability to oligomerize.

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Section: Angewandte Chemiementioning

confidence: 99%

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

Kumar

Francisco

2016

Angew Chem Int Ed

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“…Thioformaldehyde is also found toward the Galactic center, in well-known hot cores such as the Compact Ridge in Orion KL, and in outflows such as those of the Cepheus A star-forming region, where it is a tracer of high-velocity gas (Codella et al 2005) and is either desorbing from grains or rapidly forming in the gas-phase after mantle evaporation. Although an interstellar search for thioformaldehyde was carried out ( Evans et al 1970) soon after the first microwave laboratory study (Johnson & Powell 1970), the first interstellar detection was reported a few years later (Sinclair et al 1973). Meanwhile, the extension of the known rotational spectrum to higher microwave and millimeter-wave frequencies (Johnson et al 1971;Beers et al 1972) allowed predictions of a large number of unmeasured lines to be made available for interstellar identification of thioformaldehyde .…”

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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“…1,2 Few lines of H 2 CS have also been identified in the Orion KL nebula [3][4][5] and in the atmosphere of the comet Hale-Bopp. 6 Laboratory spectroscopic investigations of H 2 CS and its isotopologues have been carried out in the infrared, 7-10 microwave, and millimeter wave ranges.…”

Section: Introductionmentioning

confidence: 99%

Theoretical rotation-vibration spectrum of thioformaldehyde

Yachmenev

Polyak

Thiel

2013

The Journal of Chemical Physics

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We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H2CS. It covers 41,809 rovibrational levels for states up to J(max) = 30 with vibrational band origins up to 5000 cm(-1) and provides the energies and line intensities for 547,926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.

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A Search for the 1 ₁₀ ← 1 ₁₁ Transition of Interstellar Thioformaldehyde

Cited by 17 publications

References 4 publications

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

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

Theoretical rotation-vibration spectrum of thioformaldehyde

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A Search for the 1 10 ← 1 11 Transition of Interstellar Thioformaldehyde

Cited by 17 publications

References 4 publications

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

Heteroatom Tuning of Bimolecular Criegee Reactions and Its Implications

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

Theoretical rotation-vibration spectrum of thioformaldehyde

Contact Info

Product

Resources

About

A Search for the 1 ₁₀ ← 1 ₁₁ Transition of Interstellar Thioformaldehyde

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