Novel anions that contain one molecule each of C 60 and the polycyclic aromatic hydrocarbon coronene are generated in the gas phase by electron attachment desorption chemical ionization. Collision-induced dissociation reveals that these cluster ions are loosely bonded. Fragmentation of the mass-selected cluster anion yields, as the only products, the intact radical anions of the constituent molecules, namely, the C 60 radical anion and the coronene radical anion, in almost identical relative abundances. This result is interpreted as evidence that the cluster ion can be considered as the anion radical of one molecule solvated by the other molecule. The known very high electron affinity of C 60 (2.66 eV) and the comparable degree to which C 60 and the PAH compete for the electron suggests that dissociation may be controlled by the electron affinity of a portion of the C 60 surface, that is, in this case the kinetic method yields information on the "local" electron affinity of C 60 • The electron affinity of the bowl-shaped compound corannulene is estimated for the first time to be 0.50 ± 0.10 eV by the kinetic method by using a variety of reference compounds. Unlike coronene, corannulene reacts with C;.;t in the gas phase to form a covalently bonded, dehydrogenated cluster ion. Support for the concept of "local" electron affinity of C 60 comes from a theoretical calculation on the electronic structure of C 60 anions, which shows evidence for localization of the charge in the C 60 molecule. The possibility of electron tunneling in the C 60-coronene system is discussed as an alternative explanation for the unusual observation of equal abundances of C 60 anions and coronene anions upon dissociation of the corresponding cluster ion.
Two types of localized vibrational modes of oxygen substituting for Te in CdTe, i.e., O Te , are reported. In one, O Te is associated with a nearest neighbor ͑NN͒ vacancy as a ͑O Te -V Cd ͒ center and hence with C 3v symmetry, with its uniaxial axis along ͗111͘, whereas in the other, O Te is surrounded by all the four NN Cd's and thus possesses T d site symmetry. By an appropriate control of stoichiometry it is possible to reproducibly generate the formation of either ͑O Te -V Cd ͒ or O Te centers. These configurations are deduced from their ultrahigh resolution infrared signatures. For the ͑O Te -V Cd ͒ centers, consistent with their uniaxial symmetry, a pair of sharp local vibrational modes ͑LVM͒ are observed at 1 = 1096.78 cm −1 and 2 = 1108.35 cm −1 , the latter nearly twice as intense as the former. In the LVM spectrum of O Te centers with the full complement of NN Cd's, consistent with its T d symmetry, only one LVM signature appears at 0 = 349.79 cm −1 . With the increasing temperature, 1 and 2 approach each other and coalesce into a single triply degenerate line at 0 * for temperature T Ն T * ϳ 300 K; the uniaxial ͑C 3v ͒ symmetry of ͑O Te -V Cd ͒ transforms to T d symmetry at T * and above, acquired by the ͑O Te -V Cd ͒ centers due to the increasing rate of bond switching among the four possible O Te -V Cd ͗111͘ directions as T approaches T * . The ͑O Te -V Cd ͒ centers also display a fascinating pair of second harmonics including a coalescence at T * and beyond.
Laser forming or laser bending is a newly developed, flexible technique which modifies the curvature of sheet metal by thermal residual stresses instead of external forces. The process is influenced by many parameters such as laser parameters, material properties, and target dimensions. In this work, a pulsed Nd:YLF laser was used as the energy source. The laser beam was focused into a line shape irradiating on the stainless steel specimen to induce bending. The bending angle was measured at various processing conditions. A finite element analysis was performed with the use of a two-dimensional plane strain model to calculate the thermoelastoplastic deformation process. Experimental measurements and computational results were in good agreement. Numerical sensitivity studies were performed to evaluate the effects of the unavailable material property data at high temperature. It was found that both optical reflectivity and thermal expansion coefficient influenced the bending angle significantly, while other extrapolated material properties at high temperature yielded acceptable results.
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