Potential energy surfaces for the Ta++C2 reaction

Roszak, Szczepan; Balasubramanian, K.

doi:10.1063/1.473118

Cited by 3 publications

(4 citation statements)

References 16 publications

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“…Although the geometry optimization was successful, we had difficulty determining the vibrational frequencies and so they are not listed in Table . Roszak and Balasubramanian have performed CASSCF and MRCI calculations on TaC 2 + and found two near degenerate minima: a “T-shaped” isomer of C 2v symmetry ( 3 A 2 state) and an asymmetric linear isomer, Ta−C−C, of C ∞ v symmetry ( 3 Δ state) . It is possible that difficulties in calculating vibrational frequencies for TaC 2 using the B3P86 theoretical approach are attributable to a mixing of the bent and linear geometric descriptions within the DFT calculations.…”

Section: Resultsmentioning

confidence: 99%

“…Theoretical studies of TaC, TaC + , TaC 2 + , and TaC n + (n ) 7-13) have been reported by Balasubramanian and co-workers. [18][19][20] From their work, TaC 2 + was shown to adopt both a linear configuration of the form Ta-C-C and a "T-shaped" configuration with the former being slightly more stable. Various geometric isomers of TaC n + (n ) 7-13) were found to adopt either metallacycle, linear, bridged, atop, or metallocenic structures.…”

Section: Introductionmentioning

confidence: 99%

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Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

et al. 2000

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Neutral tantalum−carbide clusters, Ta m C n (m = 1−6, n = 1−7), have been formed in a supersonic expansion following the reaction of tantalum and acetylene in a laser ablation source. These clusters have been subjected to multiphoton ionization at 532 and 355 nm and the mass spectra recorded in a reflectron time-of-flight mass spectrometer. The cluster distributions show a drop off after m = 4 suggesting the stabilization of clusters containing four tantalum atoms. We have investigated the structures of these clusters using density functional theory and shown that the smaller clusters tend to form fragments of face-centered cubes, culminating in the formation of a distorted cube of stoichiometry Ta4C4. The structure of Ta4C4 is shown to be a distorted tetrahedron, or “butterfly”, made up of four tantalum atoms with a carbon atom bonded to each face. The theoretical calculations also indicate that clusters containing three tantalum atoms form a triangle and that there is competition for the carbon atoms to bond to either the face or the edge of the tantalum triangle.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

et al. 2000

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“…41 The charge density analyses of the ground state have shown that there is donation and back donation in the formation of a Ta-C bond. Since our experience on the VC 2 and VC 2 ϩ species has shown that the V-C bond in these clusters is similar ͑Sec.…”

Section: The Nature Of Bondingmentioning

confidence: 99%

Electronic structure and spectroscopic properties of electronic states of VC2, VC2−, and VC2+

Roszak

Majumdar

Balasubramanian

2003

The Journal of Chemical Physics

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Articles you may be interested inAn all-electron density functional theory study of the structure and properties of the neutral and singly charged M 12 and M 13 clusters: M = Sc-Zn Geometry and electronic structure of V n ( Bz ) m complexes Theoretical studies on the electronic and thermodynamic properties of several electronic states are presented for the VC 2 molecule, the VC 2 Ϫ anion, and the VC 2 ϩ cation employing state-of-the-art techniques that included up to 12 million configurations. The ground and the low-lying electronic states of these three species have been found to have C 2v triangular structures. On the basis of our computed results, we have suggested an assignment of the observed anion photodetachment spectra of VC 2Ϫ and predicted transitions that were not observed. Our computed electron affinity is in excellent agreement with experiment. The observed thermodynamic properties of reactions involving VC 2 , VC 2 Ϫ , and VC 2 ϩ are corrected using the computed gas phase properties of the molecule and the partition functions. The bent quartet states of VC 2 exhibit large dipole moments (8.65Ϫ9.3 D). d is the dipole moment in Debye. The positive value means V ϩ C Ϫ polarity of bonds and the dipole vector bisects the C-V-C apex angle for the isosceles triangle. For the linear structure it is along the molecular axis. 132

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“…Carbides are compounds formed by carbon and elements with similar or lower electronegativity, and they have many important applications in technology. − Carbides of the highly electropositive metals are saltlike, containing distinct C 4- , C 2 2- , or C 3 4- anions that release CH 4 , C 2 H 2 , or C 3 H 4 hydrocarbons, respectively, upon reaction with water. Carbide clusters have attracted a lot of attention from both theoreticians and experimentalists, − in particular, after the discovery of the “met-cars”, which consist of eight early-transition-metal atoms and six C 2 units. − Bulk copper carbide contains C 2 acetylenic units. However, there have been relatively few studies on copper carbide clusters. , However, cyclic Cu n structural motifs have been previously reported to be a building block of various organic and inorganic systems. − In particular, the triangular motif Cu 3 has been observed within organic molecules and complexes containing various ligands and bridging groups. − Interestingl...…”

Section: Introductionmentioning

confidence: 99%

Cu₃C₄^-: A New Sandwich Molecule with Two Revolving C₂^2- Units

Alexandrova¹,

Boldyrev²,

Zhai³

et al. 2005

J. Phys. Chem. A

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A combined photoelectron spectroscopy (PES) and ab initio study was carried out on a novel copper carbide cluster in the gas phase: Cu(3)C(4)(-). It was generated in a laser vaporization cluster source and appeared to exhibit enhanced stability among the Cu(3)C(n)(-) series. Its PES spectra were obtained at several photon energies, showing numerous well-resolved bands. Extensive ab initio calculations were performed on Cu(3)C(4)(-), and two isomers were identified: a C(2) structure ((1)A) with a Cu(3)(3+) triangular group sandwiched by two C(2)(2-) units and a linear CuCCCuCCCu structure (D(infinity)(h), (1)Sigma(g)(+)). A comparison of ab initio PES spectra with experimental data showed that the sandwich Cu(3)C(4)(-) cluster was solely responsible for the observed spectra and the linear isomer was not present, suggesting that the C(2) structure is the global minimum in accordance with CCSD(T)/6-311+G predictions. Interestingly, a relatively low barrier (0.4-0.6 kcal/mol) was found for the internal rotation of the C(2)(2-) units in the sandwich Cu(3)C(4)(-). To test different levels of theory in describing the Cu(m)C(n)(-) systems and lay foundations for the validity of the theoretical methods, extensive calculations at a variety of levels were also carried out on a simpler copper carbide species CuC(2)(-), where two isomers were found to be close in energy: a linear one (C(infinity)(v), (1)Sigma(+)) and a triangular one (C(2)(v), (1)A(1)). The calculated electronic transitions for CuC(2)(-) were also compared with the PES data, in which both isomers were present.

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Potential energy surfaces for the Ta++C2 reaction

Cited by 3 publications

References 16 publications

Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

Electronic structure and spectroscopic properties of electronic states of VC2, VC2−, and VC2+

Cu₃C₄^-: A New Sandwich Molecule with Two Revolving C₂^2- Units

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Potential energy surfaces for the Ta++C2 reaction

Cited by 3 publications

References 16 publications

Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

Neutral Tantalum−Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

Electronic structure and spectroscopic properties of electronic states of VC2, VC2−, and VC2+

Cu3C4-: A New Sandwich Molecule with Two Revolving C22- Units

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Cu₃C₄^-: A New Sandwich Molecule with Two Revolving C₂^2- Units