High-resolution infrared spectroscopic determination of the nν5±n vibrational energies of HCCN and DCCN

Hung, Pui Yee; Sun, Feifei; Hunt, Neil T.; Burns, Lori A.; Curl, R. F.

doi:10.1063/1.1413981

Cited by 24 publications

(28 citation statements)

References 24 publications

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“…With respect to the experimental HC1 bond distance, Brown et al 22 found that this bond is shorter than all known C-H bond lengths previously determined in other hydrocarbon molecules, suggesting that an accurate study was necessary to understand the HCCN structure. However, they obtained this short CH bond distance by assuming a linear structure, but later studies have shown that the triplet ground state of HCCN is best viewed as quasilinear [23][24][25][26][27][28][29] , and our results support that conclusion.…”

Section: A Equilibrium Structures Harmonic Frequencies and Equilibrsupporting

confidence: 82%

“…al slightly modified their previous experimental conclusion based on a microwave study, suggesting a quasilinear structure instead of a strict linear one 22 . More experimental evidence for the quasilinearity of cyanocarbene came from analysis of high-resolution rotational 23 and vibrational [24][25][26][27][28][29] spectra. McCarthy and co-workers 23 estimated the transition energies from relative intensity measurements in the microwave region.…”

Section: Introductionmentioning

confidence: 99%

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Accurate ab initio quartic force fields of cyclic and bent HC2N isomers

Inostroza

Huang

Lee

2011

The Journal of Chemical Physics

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Highly correlated ab initio quartic force field (QFFs) are used to calculate the equilibrium structures and predict the spectroscopic parameters of three HC 2 N isomers. Specifically, the ground state quasilinear triplet and the lowest cyclic and bent singlet isomers are included in the present study.Extensive treatment of correlation effects were included using the singles and doubles coupled-cluster method that includes a perturbational estimate of the effects of connected triple excitations, denoted CCSD(T). Dunning's correlation-consistent basis sets cc-pVXZ, X=3,4,5, were used, and a three-point formula for extrapolation to the one-particle basis set limit was used. Core-correlation and scalar relativistic corrections were also included to yield highly accurate QFFs. The QFFs were used together with second-order perturbation theory (with proper treatment of Fermi resonances) and variational methods to solve the nuclear Schrödinger equation. The quasilinear nature of the triplet isomer is problematic, and it is concluded that a QFF is not adequate to describe properly all of the fundamental vibrational frequencies and spectroscopic constants (though some constants not dependent on the bending motion are well reproduced by perturbation theory). On the other hand, this procedure (a QFF together with either perturbation theory or variational methods) leads to highly accurate fundamental vibrational frequencies and spectroscopic constants for the cyclic and bent singlet isomers of HC 2 N.

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Section: A Equilibrium Structures Harmonic Frequencies and Equilibrsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Accurate ab initio quartic force fields of cyclic and bent HC2N isomers

Inostroza

Huang

Lee

2011

The Journal of Chemical Physics

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“…Although there is no evidence for either species in published astronomical surveys, HSiCN ( ¼ 3:5 D [42]) and HSiNC ( ¼ 2:4 D) are highly polar, so dedicated astronomical searches are warranted. HSiCN is isovalent to HCCN, a well studied laboratory molecule that possesses a large amplitude CCH bending motion and a non-rigid structure [43]. A structural analysis is underway to determine whether HSiCN, like HCCN, also possesses large amplitude bending.…”

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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“…Many studies have revealed that there are many isomers with different kinds of geometries (linear, bent or cyclic) or different multiplicities (singlet or triplet) having similar energies for the HC 2 N molecules. [19][20][21][22][23][24][25][26][27][28][29][30] Lee et al have characterized the quasilinear triplet, bent singlet, and cyclic singlet HC 2 N isomers and determined their molecular properties with a series of highly accurate ab initio levels of theory. 27 In addition, the cyclic HC 2 N isomer was found to be an intermediate between the interconversion of the bent HCCN and the unknown bent HCNC on the hypersurface of neutral, anionic, and cationic species, where the barriers are feasible.…”

Section: -16mentioning

confidence: 99%

Theoretical Study on the Reaction Mechanism of Azacyclopropenylidene with Epoxypropane: An Insertion Process

Tan¹,

Li²

2014

Bulletin of the Korean Chemical Society

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The reaction mechanism between azacyclopropenylidene and epoxypropane has been systematically investigated employing the second-order Møller-Plesset perturbation theory (MP2) method to better understand the reactivity of azacyclopropenylidene with four-membered ring compound epoxypropane. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. It was found that for the first step of this reaction, azacyclopropenylidene can insert into epoxypropane at its C-O or C-C bond to form spiro intermediate IM. It is easier for the azacyclopropenylidene to insert into the C-O bond than the C-C bond. Through the ring-opened step at the C-C bond of azacyclopropenylidene fragment, IM can transfer to product P1, which is named as pathway (1). On the other hand, through the H-transferred step and subsequent ring-opened step at the C-N bond of azacyclopropenylidene fragment, IM can convert to product P2, which is named as pathway (2). From the thermodynamics viewpoint, the P2 characterized by an allene is the dominating product. From the kinetic viewpoint, the pathway (1) of formation to P1 is primary.

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High-resolution infrared spectroscopic determination of the nν5±n vibrational energies of HCCN and DCCN

Cited by 24 publications

References 24 publications

Accurate ab initio quartic force fields of cyclic and bent HC2N isomers

Accurate ab initio quartic force fields of cyclic and bent HC2N isomers

Silicon molecules in space and in the laboratory

Theoretical Study on the Reaction Mechanism of Azacyclopropenylidene with Epoxypropane: An Insertion Process

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