Microwave spectrum and molecular structure of silacyclopropenylidene c-C<sub>2</sub>H<sub>2</sub>Si

Izuha, Mitsuaki; Yamamoto, Satoshi; Saito, Shuji

doi:10.1139/p94-155

Cited by 22 publications

(19 citation statements)

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“…Although H 2 CSi has not been found in space [41], H 2 CCSi is a good candidate for astronomical discovery because it is much more polar ( ¼ 1:21 D versus $ 0:3 D) and because isovalent H 2 CCC has been detected in both interstellar and circumstellar sources. HSiCN and HSiNC were detected in the same molecular beam discharge source that produces strong lines of SiCN and SiNC, and precise spectroscopic constants were derived for each from the centimetre-wave data.…”

Section: Laboratory and Astronomical Discovery Of Newmentioning

confidence: 99%

Silicon molecules in space and in the laboratory

2003

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Despite the highly non-volatile nature of Si, silicon bearing molecules are a significant trace constituent of the gas associated with late-type stars and star forming regions, representing nearly 10% of the molecular species that have been identified in space. The early astronomical detection of SiO and its remarkable maser emission stimulated laboratory studies of other small silicon species that were crucial to the astronomical identifications. Although the pace of this laboratory work until recently has been slow, the application of Fourier transform microwave spectroscopy to supersonic molecular beams has overcome many experimental difficulties, yielding the detection of more than 20 new silicon chains and rings of astronomical interest during the past three years. Three of these, the rhomboidal ring SiC 3 and the isovalent linear molecules SiCN and SiNC, have now been found in space, and with dedicated searches other recently discovered silicon molecules may soon be found. A number of exotic silicon molecules of astronomical and chemical interest should be amenable to laboratory detection with present techniques.

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Section: Laboratory and Astronomical Discovery Of Newmentioning

confidence: 99%

Silicon molecules in space and in the laboratory

2003

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“…The microwave spectra of Si-1S and Si-3S have also been published. 6,21 Subsequent higher level theoretical studies have followed. 6,[22][23][24][25][26] Much less research [27][28][29][30][31] has been reported on the isovalent germanium systems.…”

Section: Introductionmentioning

confidence: 99%

From acetylene complexes to vinylidene structures: The GeC₂H₂ system

et al. 2010

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The expansion of germanium chemistry in recent years has been rapid. In anticipation of new experiments, a systematic theoretical investigation of the eight low lying electronic singlet GeC(2) H(2) stationary points is carried out. This research used ab initio self-consistent-field (SCF), coupled cluster (CC) with single and double excitations (CCSD), and CCSD with perturbative triple excitations [CCSD(T)] levels of theory and a variety of correlation-consistent polarized valence cc-pVXZ and cc-pVXZ-DK (Douglas-Kroll) (where X = D, T, and Q) basis sets. At all levels of theory used in this study, the global minimum of the GeC(2) H(2) potential energy surface (PES) is confirmed to be 1-germacyclopropenylidene (Ge-1S). Among the eight singlet stationary points, seven structures are found to be local minima and one structure (Ge-6S) to be a second-order saddle point. For the seven singlet minima, the energy ordering and energy differences (in kcal mol(-1) , with the zero-point vibrational energy corrected values in parentheses) at the cc-pVQZ-DK (Douglas-Kroll) CCSD(T) level of theory are predicted to be 1-germacyclopropenylidene (Ge-1S) [0.0 (0.0)] < vinylidenegermylene (Ge-3S) [13.9 (13.5)] < ethynylgermylene (Ge-2S) [17.9 (14.8)] < Ge-7S [37.4 (33.9)] < syn-3-germapropenediylidene (Ge-8S) [41.2 (37.9)] < germavinylidenecarbene (Ge-5S) [66.6 (61.6)] < nonplanar germacyclopropyne (Ge-4S) [67.8 (63.3)]. These seven isomers are all well below the dissociation limit to Ge ((3) P) + C(2) H(2) (X (1) Σ g+). This system seems particularly well poised for matrix isolation infrared (IR) experiments.

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“…Subsequently, a total of four C 2 H 2 Si and CNHSi molecules were also studied by high resolution spectroscopic techniques, i.e., microwave-and millimeter-wave spectroscopy. The millimeter wave spectrum of silacyclopropenylidene ͑1͒ was reported 10 as was a Fourier transform microwave ͑FTMW͒ study of H 2 CCSi ͑2͒. 11 In case of CNHSi structural isomers, HSiCN ͑7͒ and HSiNC ͑8͒ were identified in the gas phase through FTMW spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Coupled-cluster calculations of C2H2Si and CNHSi structural isomers

Thorwirth

Harding

2009

The Journal of Chemical Physics

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Results of large-scale coupled-cluster calculations of selected C(2)H(2)Si and CNHSi structural isomers are reported. Equilibrium molecular structures of a total of 12 molecules in their singlet electronic states have been calculated systematically employing the coupled-cluster singles and doubles model augmented by a perturbative correction for triple excitations (CCSD(T)) in combination with Dunning's hierarchy of correlation consistent basis sets. In addition, anharmonic force fields were calculated to yield fundamental vibrational frequencies and rotation-vibration interaction constants alpha(i) (A,B,C). The latter were used to determine empirical equilibrium structures r(e) (emp) of two molecules - silacyclopropenylidene, c-C(2)H(2)Si, and silapropadienylidene, H(2)CCSi - for which sufficient isotopic data are available from literature. Very good agreement with theoretical equilibrium structures from CCSD(T) calculations employing core-valence basis sets of quadruple and quintuple-zeta quality - i.e., cc-pwCVQZ (337 basis functions), cc-pCV5Z, and cc-pwCV5Z (581 basis functions) is found - to within 0.001 A for bond lengths and 0.1 degrees for bond angles. Theoretical ground state rotational constants of HSiCN and HSiNC compare very favorably with experimental microwave data from literature, to within 0.15% (HSiCN) and 0.1% (HSiNC) for the B(0) and C(0) rotational constants. In the case of c-C(2)H(2)Si and H(2)CCSi this agreement is even better than 0.1%. For the latter two molecules effects of higher-level electron-correlation and relativity to the equilibrium geometry as well as the electronic contributions to the rotational constants are investigated. For eight molecules not yet studied at high spectral resolution in the gas-phase theoretical molecular parameters are provided to support future laboratory investigations. Theoretical vibrational fundamentals compare well with data of eight species studied previously with infrared matrix isolation spectroscopy.

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Microwave spectrum and molecular structure of silacyclopropenylidene c-C₂H₂Si

Cited by 22 publications

References 0 publications

Silicon molecules in space and in the laboratory

Silicon molecules in space and in the laboratory

From acetylene complexes to vinylidene structures: The GeC₂H₂ system

Coupled-cluster calculations of C2H2Si and CNHSi structural isomers

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Microwave spectrum and molecular structure of silacyclopropenylidene c-C2H2Si

Cited by 22 publications

References 0 publications

Silicon molecules in space and in the laboratory

Silicon molecules in space and in the laboratory

From acetylene complexes to vinylidene structures: The GeC2H2 system

Coupled-cluster calculations of C2H2Si and CNHSi structural isomers

Contact Info

Product

Resources

About

Microwave spectrum and molecular structure of silacyclopropenylidene c-C₂H₂Si

From acetylene complexes to vinylidene structures: The GeC₂H₂ system