Ultra-violet absorption band-systems of SiS, SiSe and SiTe

Vago, E E; Barrow, R. F.

doi:10.1088/0959-5309/58/5/303

Cited by 56 publications

(32 citation statements)

References 3 publications

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“…Extensive measurements are available for many diatomics such as SiO, CS, SiS, NaCl, KCl, AlF, etc detected in this soruce, from which transitions can be assigned with confidence well into the terahertz region. For SiS, for example, all twelve possible isotopic species have been observed in the centimeter-wave band,18,19 and include rotational transitions from states as high of v = 51 (~ 43, 500 K) for the normal isotopic species, equivalent to roughly 60% of the energy to dissociate the molecule 20,21. Precise rest frequencies have also been reported for a number of the more abundant isotopic species at millimeter-wave and submillimeter-wave wavelengths 19.…”

Section: Interferometric Spectral Line Surveys: Evidence For a Rich Imentioning

confidence: 99%

Building Blocks of Dust and Large Organic Molecules: A Coordinated Laboratory and Astronomical Study of Agb Stars

McCarthy¹,

Gottlieb²,

Cernicharo³

2017

Proceedings of the 72nd International Symposium on Molecular Spectroscopy

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This article provides an overview of recent astronomical studies and a closely coordinated laboratory program devoted to the study of the physics and chemistry of carbon rich Asymptotic Giant Branch (AGB) stars. The increased sensitivity and angular resolution of high altitude ground-based millimeter-wave interferometers in the past few years has enabled molecular astronomers to determine the excitation and spatial distribution of molecules within a few stellar radii of the central star where the molecular seeds of dust are formed, and to critically assess the physicochemical mechanisms of dust formation and growth. However the astronomical studies are crucially dependent on precise laboratory measurements of the rotational spectra — both in the ground and vibrationally excited states of the normal and rare isotopic species — of the principal molecules in the inner region which appear to contain only two or three heavy atoms Much remains to be done by laboratory spectroscopists as evidenced by the large number of unassigned millimeters-wave rotational lines that are observed in the inner envelope of carbon rich AGB stars. As an illustration we refer to the example of an initial laboratory approach for establishing whether vibrationally excited SiC2 and HCN are the carriers of some of the unassigned features observed in the prototypical carbon rich AGB star IRC+10216 with ALMA. Also highlighted are ongoing laboratory studies of the silicon carbides SiC2 and SiCSi in their ground and excited vibrational states, and SiC3 in the ground vibrational state. Following the initial detection of SiC3 and SiCSi in the outer molecular envelope of IRC+10216, the laboratory spectroscopy was extended to higher frequency in support of the recent interferometric measurements. Thirty-two new millimeter-wave rotational transitions of SiCSi with J ≤ 48, Ka ≤ 3 and upper level energies Eu ≤ 484 K in the range from 178 – 391 GHz, and 35 new transitions of SiC3 with J ≤ 38, Ka ≤ 20 and Eu ≤ 875 K between 315 and 440 GHz were measured in the laboratory. In addition five to six rotational transitions in one quanta of each of the three fundamental vibrational modes of SiCSi, and the two lowest rotational transitions in the previously unexplored C–C stretching mode (ν1) of SiCC were measured in the normal and doubly substituted 13C isotopic species.

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Section: Interferometric Spectral Line Surveys: Evidence For a Rich Imentioning

confidence: 99%

Building Blocks of Dust and Large Organic Molecules: A Coordinated Laboratory and Astronomical Study of Agb Stars

McCarthy¹,

Gottlieb²,

Cernicharo³

2017

Proceedings of the 72nd International Symposium on Molecular Spectroscopy

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“…[1,2] and references therein); to the contrary studies on the heavier species are comparatively scarce. The first spectroscopic investigations of SiSe and SiTe in their monomeric forms appeared in the pioneering works of Barrow and co-workers [3,4] who observed their UV band spectra both in emission and in absorption. Subsequent investigations on the electronic spectra of silicon selenide [5][6][7][8] and silicon telluride [9,10] performed at higher resolution yielded vibrational and rotational constants of these molecules in their low-lying electronic states.…”

Section: Introductionmentioning

confidence: 99%

Rotational spectra, potential function, Born–Oppenheimer breakdown and magnetic shielding of SiSe and SiTe

Giuliano

Bizzocchi

Grabow

2008

Journal of Molecular Spectroscopy

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“…The potential energy curves and transition moments were determined by Chattopadhyaya et al (2002), using multireference singles and doubles configuration interaction (MRDCI) method, which include relativistic effective core potential (RECP). The dissociation energy (D e ) estimated by Chattopadhyaya et al (2002) is about 5.85 eV, which is an underestimation of the experimentally derived (D 0 ) value of 6.42 eV obtained from a short extrapolation of the vibrational levels of the E state assuming dissociation into 3 P 2 + 3 P 2 (223 cm −1 ) (Vago & Barrow 1946;Robinson & Barrow 1954;Huber & Herzberg 1979). However, according to Chattopadhyaya et al (2002), similar discrepancies have been found in all previous calculations employing the same methodology because of the use of limitations of the basis sets, configuration-selection and effective core potential approximation.…”

Section: R a D I At I V E A S S O C I At I O Nmentioning

confidence: 78%

Silicon monosulphide radiative association

Andreazza

Marinho

2007

Monthly Notices of the Royal Astronomical Society

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Rate coefficients for radiative association of silicon and sulphur atoms to form silicon monosulphide (SiS) molecule are estimated. The radiative association is due mainly to approach in the E1Σ+ and A1Π states of SiS. For temperatures ranging from ∼1000 to ∼14 000 K, the rate coefficients are found to vary from 8.43 × 10−17 to 2.69 × 10−16 cm3 s−1. Our calculated rate coefficient is higher than the values used in modelling the chemistry of Type Ia supernovae.

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Ultra-violet absorption band-systems of SiS, SiSe and SiTe

Cited by 56 publications

References 3 publications

Building Blocks of Dust and Large Organic Molecules: A Coordinated Laboratory and Astronomical Study of Agb Stars

Building Blocks of Dust and Large Organic Molecules: A Coordinated Laboratory and Astronomical Study of Agb Stars

Rotational spectra, potential function, Born–Oppenheimer breakdown and magnetic shielding of SiSe and SiTe

Silicon monosulphide radiative association

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