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Nonrelativistic and relativistic calculations were performed for the UF5 monomer. Relativistic effects have a major impact on chemical bonding where molecules include heavy elements like uranium. Bond overlap population analysis showed that the UF5 monomer changes between D3h and C4v geometries. The UF5 monomer has structural flexibility that comes from its atomic orbitals and their wide angle electron distributions when there is hybridization involving the U 6d atomic orbital.

We have examined the infrared (IR) spectra of electron-beam (EB) irradiated C60 films, using in situ IR spectroscopy in the temperature range of 60–300 K. The irradiation-time evolution of the IR spectra shows that two highly intense new peaks finally appear around 565 and 1340 cm-1 when the EB-induced C60 polymerization was saturated. To determine the cross-linked structure of the polymer explicitly, we have compared the IR spectra with theoretical spectra obtained from the cross-linked structure of all C120 stable isomers derived from the general Stone–Wales (GSW) rearrangement, using first-principles density-functional calculations. Since each C120 isomer has the same cross-linked structure as that of its corresponding one-dimensional (1D) C60 polymer, the IR modes obtained from the cross-linked structure of C120 are close to those obtained from the corresponding 1D polymer. Comparison between the experimental and theoretical IR spectra suggests that the 1D peanut-shaped C60 polymer has a cross-linked structure roughly similar to that of the P08 peanut-shaped C120 isomer. [ABSTRACT FROM AUTHOR]

The crystal structure and surface/interface morphology of zinc-octaethylporphyrin [Zn(OEP)] films deposited on an indium tin oxide (ITO) substrate spin coated with 3,4- polyethylenedioxythiophene:polystyrenesulfonate (PEDOT:PSS) have been investigated using x-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. XRD results indicated that there are two kinds of grains with their sizes of approximately 20 nm that is independent of film thickness and substrate temperature. One has a diffraction plane with an interplanar distance of 1.12 nm and with its orientation parallel to the substrate, whereas the other has a diffraction plane with an interplanar distance of 1.24 nm and with that inclined mainly by 60° to the substrate. The abundant ratio of the two grains was controlled to some extent by varying film thickness and substrate temperature. Cross-sectional SEM images showed that a part of Zn(OEP) molecules are incorporated into PEDOT:PSS for its film thickness smaller than 130 nm, while that Zn(OEP) whiskers begin to grow for its film thickness exceeding 130 nm. [ABSTRACT FROM AUTHOR]

The crystal structure and molecular orientation of zinc-octaethylporphyrin [Zn(OEP)] thin films deposited on a SiO2/Si(111) substrate have been investigated using x-ray diffraction (XRD) and infrared multiple-angle incidence resolution spectroscopy (MAIRS), respectively. XRD results show that the Zn(OEP) thin films have two kinds of crystallites with a diffraction plane (2θ=7.9°) parallel to the substrate and with that (2θ=7.1°) inclined mainly by 60°–70° to the substrate. Comparison with simulated XRD results of the Zn(OEP) single crystal indicates that the diffraction angle of 2θ=7.9° is consistent with that of the (011) plane of the single crystal, while the angle of 2θ=7.1° is slightly different from that of 7.3° corresponding to the (010) plane of the single crystal. On the other hand, MAIRS results demonstrate that Zn(OEP) molecules in the crystallite corresponding to 2θ=7.9° are inclined by 52.2±0.9° to the substrate, which is in a good agreement with that of ca. 50° estimated from the Zn(OEP) single crystal structure. In addition, these crystalline sizes are estimated to be approximately 20 nm and independent of film thickness. Accordingly, it can be concluded from the XRD and MAIRS results that the Zn(OEP) films have two kinds of grains. One has the single crystal structure, in which Zn(OEP) molecules are inclined by 52.2°±0.9° to the substrate. On the other hand, the other has a crystal structure close to the single crystal, in which Zn(OEP) molecules would be inclined by 10°–20° to the substrate. [ABSTRACT FROM AUTHOR]

The infrared (IR) spectra of electron-beam (EB) irradiated [C.sub.60] films are examined by using in situ IR spectroscopy. The cross-linked structure of the polymer is determined by comparing the IR spectra with theoretical spectra obtained from the cross-linked structure of all [C.sub.120] stable isomers derived from the general Stone-Wales (GSW) rearrangement by using first-principles density functional calculations.

The crystallinity and surface morphology of zinc octaethylporphyrin, Zn(OEP), thin films deposited on an indium-tin-oxide substrate are examined by using x-ray diffraction and scanning electron microscopy. The results have shown that the Zn(OEP) film formed at room temperature(RT) is amorphous and its surface morphology is smooth, whereas the film deposited at 474 K is crystalline and its surface morphology is rough when compared to that formed at RT.

The combination analysis of the valence XPS, C KAplha XES, and AES for the allotropes by deMon DFT calculations is demostrated using the model adamantane derivative (C10H12(CH3)(sub 4)), pyrene (C16H10) and C60 molecules respectively. The theoretical valence photoelectron, C KAlpha X-ray emission, and Auger electron spectra for the allotropes are in good accordance with the experimental ones.

Focuses on the vibrational spectra and structures of homogeneous and mixed UF[sub 6] clusters. Description of the frequency shift approach and intermolecular potential model; Characteristics of the UF[sub 6] homogeneous structures; Results of frequency shift calculations for homogeneous and mixed UF clusters.

Studies a site-site intermolecular potential model for UF[sub 6] clusters, featuring exchange, dispersion, electrostatic and induction terms. Parameters of the potential adjusted to monomer transition dipole moment; Determination of the UF[sub 6] cluster structures; Contributions of various potential terms to frequency shifts.

We investigated the electrical properties of a two-dimensionally (2D) hexagonal C60 photopolymer, using four-probe measurements in air at room temperature. The current–voltage curve shows that the photopolymer exhibits nondoped semiconducting behavior. This behavior is consistent with the theoretical prediction that a 2D hexagonal C60 polymer with a crosslinkage of a [2+2] cycloadditional four-member ring between adjacent C60 molecules is semiconducting [S. Okada and S. Saito, Phys. Rev. B 59, 1930 (1999)]. The origin of these semiconducting properties is discussed on the basis of density-functional calculations for the valence molecular orbitals of the dumbbell C120, which is regarded as a basic unit of the [2+2] crosslinkage of the 2D photopolymer. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Optimized three-dimensional (3D) cell structures and energy bands of fused (peanut-shaped) C60 polymers (p55 and p66) have been investigated using the first-principles pseudopotential approach within the local density approximation of the density functional theory. We found that the resulting electronic structure is either metal or semiconductor depending on the shape of the polymer chains and the unit cell structure. [ABSTRACT FROM AUTHOR]

The normal modes of peanut-shaped C120 fullerenes, which appear as stable intermediate isomers between the [2+2] dumbbell C120 and the completely coalesced C120 nanotube [H. Ueno, S. Ōsawa, E. Ōsawa, K. Takeuchi, Full. Sci. Technol. 6, 319 (1998)], were investigated by semi-empirical AM1 method. It was found that the peanut-shaped C120 isomers have a feature of infrared (IR) absorption band in the range 1300–1400 cm–1, which is attributed to the in-plane atomic motions in their negative curvature region. [ABSTRACT FROM AUTHOR]

Non-orthogonal tight-binding molecular-dynamics is employed to calculate structural and vibrational properties of C36 and its oligomers (C36) M = 2, 3, 4. The lowest energy configuration of the C 36 cage is confirmed to have D 6h symmetry. For the dimer, too, the D 2h structure reported in the literature is found. The vibrational spectrum is identified with the power spectrum of the displacement autocorrelation function. Additional vibrational properties are extracted from the dynamical matrix. For the monomer, fair agreement with available ab initio calculations is achieved, with comparatively smaller deviations in the Raman-frequencies than for published semi-empirical calculations. The features of the vibrational modes are correlated with the structural properties of the oligomers. [ABSTRACT FROM AUTHOR]

A photoirradiated potassium-doped C60 film has been studied by Fourier transform mass spectrometry (FT-MS) and by in situ high-resolution Fourier transform infrared spectroscopy (FT-IR) in combination with tight-binding IR calculations. The results of FT-MS and FT-IR strongly suggest that C120 bucky peanuts, which have been theoretically predicted to be stable, were formed in the photoirradiated film. [ABSTRACT FROM AUTHOR]

Irradiation of ultraviolet-visible light onto a C[sub 60] monolayer on Si(111)(&radic3; × &radic3;)R30°-Ag resulted in a chemical reaction between adjacent C[sub 60] molecules, as confirmed by scanning tunneling microscopy (STM) images. The major photoinduced products were double-bonded (two covalent C-C bonds between molecules) C[sub 60] dimers and linear trimers. We also found single-bonded (single covalent bond between molecules) C[sub 60] dimers and linear trimers, and two-dimensional C[sub 60] oligomers as minor products. Observed atomic geometry of the nonbonding contact between a C[sub 60] dimer (or a trimer) and a neighboring dimer (or a trimer), which are parallel to each other regarding their axes, is different from that reported bet-ween C[sub 60] molecules in three-dimensional C[sub 60] crystals, where there is no interaction with a substrate. [ABSTRACT FROM AUTHOR]