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The increasing use of high-sulfur coal contradicts with the stringent environmental pressure in metallurgical industry. Microwave has been confirmed to have efficient effect for coal desulfurization. However, the removal behavior of thiophenic sulfur, as the most difficult sulfur to remove from coal, is still unclear in microwave field. In this work, the feasibility of removing thiophenic sulfur from coal by microwave was evaluated by dielectric properties test, the chemical thermodynamics and kinetics of thiophenic sulfur migration with microwave irradiation were further analyzed by density functional theory (DFT) calculation. Dielectric properties test indicates that thiophenic sulfur is strong for converting electric field energy to heat energy than coal, which means the thiophenic sulfur will be selectively heated in the process of coal desulfurization by microwave. The magnetic loss powers of coal and thiophenic sulfur are very small and can be ignored. DFT calculation shows that under microwave irradiation, the energy barrier and activation energy of rate-limiting step for thiophenic sulfur removal decrease by 7.6 kJ/mol and 2.24 kcal/mol, and the logarithm of rate constant increases by 11.2 s−1. It suggests that the thiophenic sulfur removal is promoted by catalyzing the breaking of C–H and C–C bonds. In addition, the optimal removal path of thiophenic sulfur is also changed, accompanying the variation of sulfur-containing products from carbon monosulfide (CS) to thioketene (C2H2S). These findings reveal the catalytic mechanism of microwave on the thiophenic sulfur removal from coal, which are conducive to the sustainable utilization of high-sulfur coal in metallurgy process.

We report the first survey of molecular emission from cometary volatiles using standalone Atacama Compact Array (ACA) observations of the Atacama Large Millimeter/Submillimeter Array (ALMA) toward comet C/2015 ER61 (PanSTARRS) carried out on UT 2017 April 11 and 15, shortly after its April 4 outburst. These measurements of HCN, CS, CH$_3$OH, H$_2$CO, and HNC (along with continuum emission from dust) probed the inner coma of C/2015 ER61, revealing asymmetric outgassing and discerning parent from daughter/distributed source species. This work presents spectrally integrated flux maps, autocorrelation spectra, production rates, and parent scale lengths for each molecule, and a stringent upper limit for CO. HCN is consistent with direct nucleus release in C/2015 ER61, whereas CS, H$_2$CO, HNC, and potentially CH$_3$OH are associated with distributed sources in the coma. Adopting a Haser model, parent scale lengths determined for H$_2$CO (L$_p$ $\sim$ 2200 km) and HNC (L$_p$ $\sim$ 3300 km) are consistent with previous work in comets, whereas significant extended source production (L$_p$ $\sim$ 2000 km) is indicated for CS, suggesting production from an unknown parent in the coma. The continuum presents a point-source distribution, with a flux density implying an excessively large nucleus, inconsistent with other estimates of the nucleus size. It is best explained by the thermal emission of slowly-moving outburst ejectas, with total mass 5--8 $\times$ 10$^{10}$ kg. These results demonstrate the power of the ACA for revealing the abundances, spatial distributions, and locations of molecular production for volatiles in moderately bright comets such as C/2015 ER61.

Artículo escrito por un elevado número de autores, solo se referencia el que aparece en primer lugar, el nombre del grupo de colaboración, si lo hubiere, y los autores pertenecientes a la UAM, Context. Carbon monosulphide (CS) is among the most abundant gas-phase S-bearing molecules in cold dark molecular clouds. It is easily observable with several transitions in the millimeter wavelength range, and has been widely used as a tracer of the gas density in the interstellar medium in our Galaxy and external galaxies. However, chemical models fail to account for the observed CS abundances when assuming the cosmic value for the elemental abundance of sulfur. Aims. The CS+O → CO + S reaction has been proposed as a relevant CS destruction mechanism at low temperatures, and could explain the discrepancy between models and observations. Its reaction rate has been experimentally measured at temperatures of 150-400 K, but the extrapolation to lower temperatures is doubtful. Our goal is to calculate the CS+O reaction rate at temperatures, The research leading to these results has received funding from MICIU (Spain) under grants FIS2017-83473-C2, AYA2016-75066- C2-2-P, ESP2017-86582-C4-1-R, AYA2017-85111-P, PID2019-105552RB-C41 and PID2019-106235GB-I00. N.B. acknowledges the computing facilities by TUBITAK-TRUBA, and O.R. and A.A. acknowledge computing time at Finisterre (CESGA) and Marenostrum (BSC) under RES computational grants ACCT-2019-3-0004 and AECT-2020-1-0003. SPTM acknowledges the European Union’s Horizon 2020 research and innovation program for funding support under agreement No 639459 (PROMISE)

This paper proposes a universal combination of chemical modifiers for sulfur determination through carbon monosulfide (CS) monitoring by high-resolution-continuum source graphite furnace molecular absorption spectrometry and solid sampling analysis. Three certified reference materials containing sulfur (NIST 8414, 8415 and 1648a) and a variety of samples were submitted to the proposed method. The CS molecule was monitored at 258.056 nm using a platform coated with Zr and a combination of 10 μL Ca (1 g L−1) and 4 μL Pd (10 g L−1) placed over the sample. The best pyrolysis and vaporization temperatures were 400 °C and 2300 °C, respectively. Aqueous standard solutions were employed to obtain the calibration curve, using a mix of three sulfur compounds (ammonium sulfate, L-cysteine, and thiourea), and the linear range was from 0.033 μg to 4 μg S. The LOQ and the characteristic mass were 0.033 μg S and 0.011 μg S, respectively, while the accuracy was evaluated using different organic and inorganic reference materials, and good agreement (higher than 93%) with the certified values for S was observed.

An indirect method for the determination of cysteine in pharmaceutical formulations involving the monitoring of CS (carbon monosulfide) molecular absorption bands using high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) is reported. The best conditions for the determination were based on the sum of the absorbance signals of the molecular transition lines for CS at 258.034 and 258.056 nm with a pyrolysis temperature of 1000 °C and a volatilization temperature of 2400 °C using Pd/Mg as a chemical modifier. The linear range for cysteine was 1.4 to 100 mg kg−1 with a limit of detection and limit of quantification of 0.4 and 1.3 mg kg−1, respectively. The precision, evaluated as relative standard deviation (RSD), was 3.7% (n = 10) for a sample containing 25.0 mg kg−1 of cysteine. The accuracy of sulfur determination was evaluated using a standard reference material (NIST-SRM-1573a tomato leaves) and concordant values were observed within the 95% confidence interval. The method was successfully applied to the analysis of pharmaceutical formulation samples containing cysteine, lysine, and alanine. The concentrations of cysteine found in the samples were between 9.8 and 20.1 mg kg−1.

WOS: 000440769400013 PubMed ID: 29998966 The determination of sulfur in apricot and grape samples was performed by using high-resolution continuum source electrothermal molecular absorption spectrometry based on vaporization of the carbon monosulfide (CS) molecule. CS forms in the gas phase without the addition of any molecule-forming element, since graphite cuvette contains plenty of carbon as well as food samples. A mixture of 15 mu g Pd + 10 mu g Mg was used in solution as the chemical modifier. The best sensitivity was obtained at 900 degrees C of the pyrolysis temperature with a K2SO4 calibration solution. The calibration plot drew a linear path between 50 and 1600 ng of sulfur, and the limit of detection was found to be 23 ng. The accuracy of the method was confirmed with the use of a standard reference material (Rice Flour, NIST SRM 1568a). The sulfur content in chemically dried apricot samples (1987 +/- 45 mg/kg) was determined to be higher than that of apricot samples dried under sunshine. Council of Higher Education of TurkeyMinistry of National Education - Turkey [2547/39] The authors wish to thank financial support of the foundation of The Council of Higher Education of Turkey (No. 2547/39). This study was funded by No. 2547/39

We use density functional theory (DFT) to predict the chemical reactivity of CS molecule on third-row maingroup dicarbides, C2X (X = K-Br). An analysis of the frontier molecular orbitals (FMOs) of bare C2X clusters suggests that carbon atoms of C2X clusters is the most active site for CS interaction. Using Bader’s approach, the nature of interactions between CS molecule and the host C2X clusters has been studied by examining computational parameters at the bond critical points (BCPs) of the clusters. It is noted that, in all the clusters, ρ C C 2 X - C CS > 0.30 a.u. with negative ∇ 2 ρ C - C at BCPs of carbon atoms of both C2X and CS, indicating a shared-electron interaction between C2X and CS.

The feasibility of direct laser cooling of SiH, GeH, SnH, and PbH is investigated and assessed based upon first principles. The internally contracted multi-reference configuration interaction method with the Davidson correction is applied. Very good agreement is obtained between our computed spectroscopic constants and the available experimental data. We find that the locations of crossing point between the B2Σ- and A2Δ states have the tendency of moving downwards from CH to SnH relative to the bottom of the corresponding A2Δ potential, which precludes the laser cooling of GeH, SnH, and PbH. By including the spin-orbit coupling effects and on the basis of the A 2 Δ 5 / 2 → X 2 Π 3 / 2 transition, we propose a feasible laser cooling scheme for SiH using three lasers with wavelengths varying from 400 to 500 nm, which features a very large vibrational branching ratio (0.9954) and a very short radiative lifetime (575 ns). Moreover, similar studies are extended to carbon monosulfide (CS) with a feasible laser cooling scheme proposed. The importance of electronic state crossing in molecular laser cooling is underscored, and our work suggests useful caveats to the choice of promising candidates for producing ultracold molecules.

Carbon monosulfide was detected in outer space by rovibrational spectroscopy of the X 1Σ+ state and A 1Π – X 1Σ+ system. This work calculated the potential energy curves and dipole moment functions of the X 1Σ+0+ and A 1Π1 states, and computed the transition dipole moments between the two states employing the CASSCF method, followed by the valence icMRCI approach. Core-valence correlation and scalar relativistic corrections were included. The extrapolation of potential energies to the complete basis set limit was performed. The spin-orbit coupling effect was included. The Einstein A coefficients, band origins, and oscillator strengths were calculated for the rovibrational transitions when J ≤ 150. The rovibrational transitions of the X 1Σ+0+ and A 1Π1 states became very weak when Δυ ≥ 6. The Einstein A coefficients of vibronic emissions of the A 1Π1 – X 1Σ+0+ system were large, indicating that the emissions were able to be measured easily through spectroscopy. Several rovibrational transitions of the A 1Π1 – X 1Σ+0+ system were analysed in detail. The distribution of radiative lifetime varying as rotational quantum number was calculated. The results obtained in this work agree well with the available experimental values.

The transition dipole moments of the dipole–allowed transitions between the X2Σ+, A2Π, B2Σ+, 22Π, 12Σ–, and C2Δ states of the carbon monosulfide cation were calculated using the complete active space self–consistent field method, followed by the internally contracted multireference configuration interaction approach. The transition dipole moments of the spin–forbidden transitions from the a4Σ+ state to the X2Σ+ and A2Π states were computed. The radiative lifetimes were of the order of 1 – 10 µs, 100 ns, 1 µs, 10 – 100 µs, and 1 – 10 µs for the A2Π, B2Σ+, 22Π, 12Σ–, and C2Δ states, respectively. The transition frequencies, Einstein A coefficients, and Franck–Condon factors of all these spontaneous vibronic emissions from these systems were calculated. The emissions from the A2Π – X2Σ+, B2Σ+ – X2Σ+, B2Σ+ – A2Π, 22Π – A2Π, and C2Δ – A2Π systems were strong, suggesting that the 22Π state could be measured in a spectroscopy experiment via 22Π – A2Π transition. Those from the 22Π – B2Σ+, 12Σ– – 22Π, and C2Δ – 22Π systems were weak. The radiative lifetimes of the a4Σ+1/2 and a4Σ+3/2 states were approximately 10 ms. Among these spin–forbidden transitions, the emissions from the a4Σ+3/2 – A2Π3/2 system were relatively strong. The radiative–lifetime distribution of each vibrational level versus the rotational quantum number was evaluated for the A2Π, B2Σ+, 22Π, 12Σ–, C2Δ, and a4Σ+ states.

Numerous experimental and theoretical investigations studied the transition properties of the A1Π – X1Σ+ system of carbon monosulfide. However, only a few transition properties are currently available except for the A1Π state. Therefore, this study calculated the properties of the dipole-allowed transitions arising from the 11Σ–, 11Δ, 21Σ+, a3Π, 13Σ+, d3Δ, and e3Σ– states and the spin–forbidden transition from the a3Π to the X1Σ+ state. The radiative lifetimes were approximately 10 ns for the 21Σ+ state, 10 μs for the e3Σ– state, 10 – 100 μs for the d3Δ state, and 10 – 1000 μs for the 13Σ+ state. The emissions from the 21Σ+ – X1Σ+ system were strong. The radiative lifetimes were of the order of 0.1 – 1000 ms for the 11Δ state and 0.1 – 105 ms for the 11Σ– state. The lower the vibrational level of the 11Δ and 11Σ– states was, the longer the radiative lifetime became, suggesting that the spontaneous emissions arising from the lower vibrational levels of the two states were difficult to be measured through spectroscopy. The radiative lifetimes were of the order of 1 – 10 and 1 ms for the a3Π1 and a3Π0+ states, respectively; whereas those of the a3Π2 and a3Π0– states were extremely long. The radiative–lifetime distribution varying with the rotational angular quantum number J was investigated at J ≤ 70 for a particular vibrational level of the 11Σ–, 11Δ, 21Σ+, a3Π, 13Σ+, d3Δ, e3Σ–, a3Π1, and a3Π0+ states.

This paper investigates the first sigma satellite band, which is by far the most prominent, in the valence photoelectron spectra for a set of isoelectronic diatomic molecules: carbon monoxide, carbon monosulfide, carbon monoselenide, silicon monoxide and boron monofluoride. In particular, we analyze the effect of the electronic structure, with the change of the atomic pair along the row and column of the periodic table on the position of the satellite peak as well as on the related dynamical observables profiles. For this investigation, highly correlated calculations have been performed on the primary ionic states and the satellite band for all the molecules considered. Cross sections for the primary ionic states, calculated using Dyson orbitals, have been compared with those obtained with Hartree-Fock and Density Functional Theory to probe the impact of the correlation in the bound states on the photoionization observables. Limitations of a simple intensity borrowing mechanism clearly result from the analysis of the satellite state, characterized by different features with respect to the relevant primary states.

The 29 reactions linking carbon monosulfide (CS) to methyl mercaptan (CH3SH) via ten intermediate radicals and molecules have been characterized with relevance to surface chemistry in cold interstellar ices. More intermediate species than previously considered are found likely to be present in these ices, such as trans- and cis-HCSH. Both activation and reaction energies have been calculated, along with low-temperature (T > 45~K) rate constants for the radical-neutral reactions. For barrierless radical-radical reactions on the other hand, branching ratios have been determined. The combination of these two sets of information provides, for the first time, quantitative information on the full H + CS reaction network. Early on in this network, that is, early on in the lifetime of an interstellar cloud, HCS is the main radical, while later on this becomes first CH2SH and finally CH3S., Accepted for publication in A&A Lett

The absorption cross sections, as important spectroscopic data, can be used for the identification and quantitative measurement of components. However, in view that carbon monosulfide (CS) is unstable and highly reactive, it is difficult to measure the absorption cross sections of CS. Therefore, a method for measuring absorption cross sections of CS based on the dynamic equilibrium between carbon disulfide (CS2) and CS in the photolysis CS2 is proposed in the paper, and the absorption cross sections of CS are obtained for the first time. Firstly, the method for evaluating CS2 concentrations is introduced, and the calculation formula of CS2 concentrations is given. Secondly, CS2 is converted to CS by increasing the intensity of incident light. Factors affecting CS2 conversion efficiency, such as the flow rate of CS2 and the intensity of incident light, are studied. Next, according to the conversion relationship between CS2 and CS, the CS concentration has been obtained by measuring the change of CS2 concentration. Finally, the CS absorption cross sections of (0.29 ± 0.01) × 10−16 cm2/molecule and (2.15 ± 0.04) × 10−16 cm2/molecule are provided at wavelengths of 250.88 nm and 257.60 nm, respectively.

Herein we show using theoretical predictions that carbon monosulfide compounds exhibit a variety of layered nanostructures, such as chain arrays, monolayers, and thin films. We show that semiconductor chain arrays are the most stable because they are mainly dimensionality driven by sp2 hybridization of the carbon orbitals. In contrast to the thin films, the monolayers are stable at room temperature in a semiconductor phase, which is followed in energy by a metallic phase. Moreover, we study a semiconductor-to-metal phase transition in the carbon monosulfide monolayers by strain engineering to control the conductivity and carrier mobility., This work was partially supported by Projects FIS2013-48286-C02-01-P and FIS2016-76617-P of the Spanish Ministry of Economy and Competitiveness MINECO, the Basque Government under the ELKARTEK project (SUPER), and the University of the Basque Country (Grant No. IT-756-13).

A coherent picture is constructed on the Galaxy's H I, CO and CS emissions in the region |l| ≤ 10°, |b| ≤ 0.5°. The flow of gas at the Galactic Centre is dominated by a bar that has corotation at r = 2.4 ± 0.5 kpc, which we view at an angle of 16 ± 2° from its major axis. The first CO emission arises where gas is obliged to switch from x 1 orbits to x 2 orbits in the notation of Contopoulos. This gives rise to a shock and a clear signature in the (l, v) diagram. The great Galactic Centre molecular clouds such as Sgr B are on x 2 orbits.

A new series of compounds with a sulfur-carbon triple bond-SCX(2+), SCXF(+), and SCXF2 (X = Be, Mg, Ca)-were investigated using quantum chemical computations. The B3LYP, M06-2X, MP2, CCSD, and G4 methods were employed to predict the structures, harmonic vibrational frequencies, Wiberg bond indices, and adiabatic bond dissociation energies (ABDEs) for these compounds. When calculated at the B3LYP/cc-pVTZ level, the S≡C bonds were found to be rather short: 1.4855-1.4984, 1.4893-1.5078, and 1.5123-1.5184 Å for the doubly charged cations, singly charged cations, and neutral molecules, respectively. Interestingly, they are much shorter than in the strong sulfur-carbon triple bond in carbon monosulfide (1.5371 Å). Moreover, NBO analysis together with the results for the structures and Wiberg bond indices indicated that the S≡C bonds in SCX(2+), SCXF(+), and SCXF2 (X = Be, Mg, Ca) should be strong triple bonds. Further, the ABDE values of S≡C in SCX(2+) (209.8-250.6 kcal/mol) and SCXF(+) (174.6-217.6 kcal/mol), but not SCXF2 (150.5-174.4 kcal/mol), are larger than that of S≡C in carbon monosulfide (170.7 kcal/mol); however, upon comparing them with previously published data on other compounds with sulfur-carbon triple bonds, the S≡C bonds in SCXF2 molecules appear to be much stronger than those S≡C triple bonds. In general, all of the results calculated in this work clearly indicate that the SCX(2+), SCXF(+), and SCXF2 (X = Be, Mg, Ca) species each contain a strong sulfur-carbon triple bond.

In Jupiter's stratosphere, gaseous carbon monosulfide (CS) was first discovered in 1994 by millimeter and ultraviolet observations as a product induced by the collision of comet Shoemaker–Levy 9 (SL9). To constrain sulfur chemistry, in 2013, 19 years after the SL9 event, we observed Jupiter's stratospheric CS J = 7 − 6 rotational transition at 0.8 mm wavelength by using the Atacama Submillimeter Telescope Experiment 10 m single-dish telescope. The CS molecular line was successfully detected with 120 mK intensity in the antenna temperature scale. The obtained CS total mass shows ~90% decrease relative to that observed in 1998. From the line shape analysis, CS is suggested to be present above the mbar pressure level, which is comparable to that determined in 1998.