Showing papers on "Dodecahedrane published in 2005"
TL;DR: The inelastic neutron scattering spectrum calculated from the computed normal modes for the T(h) molecule in the lattice agrees quantitatively with experiment when overtone and combination transitions are included and allowance is made for anharmonicity of the C-H stretch motion.
Abstract: The Raman spectrum of crystalline dodecahedrane, C20H20, a species of nominal Ih symmetry, exhibits splitting of the Hg Raman active modes. The Raman inactive gerade vibrations of Gg, T1g, and T2g symmetry are found to have weak Raman activity. The IR forbidden vibrations of T2u, Gu, and Hu type have moderate IR activity. All of this is consistent with the Th site symmetry. A treatment of the structure and vibrations of dodecahedrane using a periodic lattice DFT method results in a slightly distorted Th structure with six C−C bonds that are 0.001 A longer than the other 24. The vibrational spectrum computed for this structure exhibits splittings of the Hg modes that are consistent with the observed spectra, but the computed splittings are larger than observed in room-temperature data. A complex pattern observed in the C−H stretching region is assigned. The inelastic neutron scattering spectrum calculated from the computed normal modes for the Th molecule in the lattice agrees quantitatively with experimen...
27 citations
TL;DR: In this paper, structures, energies, and vibrational frequencies for two C50H40 isomers with three dodecahedrane cages sharing two pentagons at the B3LYP/6-31G* level of theory were calculated.
Abstract: Structures, energies, and vibrational frequencies have been calculated for two C50H40 isomers with three dodecahedrane cages sharing two pentagons at the B3LYP/6-31G* level of theory. Thus, two C50H40 isomers have the form of coplanar tri-dodecahedrane-cage molecules. The symmetry of one isomer is D5d and that of another is C2V. Heats of formation and vertical ionization energies for two C50H40 isomers have been estimated in this study. Heats of formation as well as vibrational analysis indicate that two C50H40 isomers enjoy sufficient stability to allow for its experimental preparation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
6 citations
TL;DR: Using geometry optimization and DFT method at the B3LYP/6-31G* level of theory for C40H30, an equilibrium geometry is identified that has the form of two dodecahedrane cages linked by five carbon-carbon single bonds as discussed by the authors.
Abstract: Using geometry optimization and DFT method at the B3LYP/6-31G* level of theory for C40H30, an equilibrium geometry is identified that has the form of two dodecahedrane cages linked by five carbon–carbon single bonds. Thus, this molecule is a tri-cage molecule with two dodecahedrane cages at both ends and one pentaprismane cage in center. Vibrational frequencies and the infrared spectrum are computed at the same level of theory. The heat of formation for C40H30 has been estimated in this paper. The heat of formation of C40H30 as well as the vibrational analysis indicates that this molecule enjoys sufficient stability to allow for its experimental preparation.
5 citations
TL;DR: In this paper, the structure, energies, and vibrational frequencies of two C30H20 isomers with a dodecahedrane cage and two pentaprismane cages at the B3LYP/6-31G* level of theory were calculated.
Abstract: Structures, energies, and vibrational frequencies have been calculated for two C30H20 isomers with a dodecahedrane cage and two pentaprismane cages at the B3LYP/6-31G* level of theory. Thus, two C30H20 isomers have the form of coplanar tri-cage molecules. The symmetry of one C30H20 isomer is of D5d and that of another is of C2V. The heat of formation for two C30H20 isomers have been estimated. Heats of formation of two C30H20 isomers as well as the vibrational analysis indicate that two C30H20 isomers enjoy sufficient stability to allow for its experimental preparation. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
3 citations