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The energy cost for P atom intercalation and corresponding structural implications during formation of Fullerene-like Phosphorus carbide (FL-CPx) were evaluated within the framework of Density Functional Theory. Single P atom interstitial defects in FL-CPx are energetically feasible and exhibit energy cost of 0.93-1.21 eV, which is comparable to the energy cost for experimentally confirmed tetragon defects and dangling bonds in CPx. A single P atom intercalation event in FL-CPx can increase the inter-sheet distance from 3.39-3.62 angstrom to 5.81-7.04 angstrom. These theoretical results are corroborated by Selected Area Electron Diffraction characterization of FL-CPx samples.

The lattice equation of motion and a numerical solution of the time-dependent Schrodinger equation provide us with amicroscopic picture of charge transport in highly ordered molecular crystals. We have chosen the pentacene single crystal as a model system, and we study charge transport as a function of phonon-mode time-dependent fluctuations in the intermolecular electron transfer integral. For comparison, we include similar fluctuations also in the intramolecular potentials. The variance in these energy quantities is closely related to the temperature of the system. The pentacene system is shown to be very sensitive to fluctuation in the intermolecular transfer integral, revealing a transition from adiabatic to nonadiabatic polaron transport for increasing temperatures. The extension of the polaron at temperatures above 200 K is limited by the electron localization length rather than the interplay between the electron transfer integral and the electron-phonon coupling strength., QC 20110325

A synthetic strategy was developed for the preparation of porphyrins containing between one and four stereogenic centers, such that their molecular weights vary only as a result of methyl groups which give the chiral forms. The low-dimensional nanoscale aggregates of these compounds Reveal the profound effects of this varying molecular chirality on their supramolecular structure and optical activity. The number of stereogenic centers influences significantly the self-assembly and chiral structure of the aggregates of porphyrin molecules described here. A scanning tunneling microscopy study of monolayers on graphite shows that the degree of structural chirality with respect to the surface increases almost linearly with the number of stereogenic centers, and only one handedness is formed in the monolayers, whereas the achiral compound forms a mixture of mirror-image domains at the surface. In solution, four hydrogen bonds induce the formation of an H-aggregate, and circular dichroism measurements and theoretical studies indicate that the compounds self-assemble into helical structures. Both the chirality and stability of the aggregates depend critically on the number of stereocenters. The chiral porphyrin derivatives gelate methylcyclohexane at concentrations dependent on the number and position of chiral groups at the periphery of the aromatic core, reflecting the different aggregation forces of the molecules in solution. Increasing the number of stereogenic centers requires more material to immobilize the solvent, in all likelihood because of the greater solubility of the porphyrins. The vibrational circular dichroism spectra of the gels show that all compounds have a chiral environment around the amide bonds, confirming the helical model proposed by calculations. The morphologies of the xerogels (studied by scanning electron microscopy and scanning force microscopy) are similar, although more fibrous features are present in the molecules with fewer stereogenic cent, QC 20140826

X-ray absorption spectra have been determined for ethylene and free base phthalocyanine at the carbon K -edge with use of the complex polarization propagator method combined with Kohn-Sham density functional theory and the Coulomb attenuated method B3LYP exchange-correlation functional. Apart from isolated molecules, the study includes π -stacked systems of the phthalocyanine dimer and the ethylene dimer, trimer, tetramer, and pentamer. For ethylene, π -stacking involves a reduction in transition energy of the valence π* -band by some 70 meV and large spectral changes (regarding also shape and intensity) of the Rydberg bands. For phthalocyanine, there are large spectral changes in the entire valence π * -part of the spectrum. © 2009 American Institute of Physics., References: Hobza, P., (2008) Phys. Chem. Chem. Phys., 10, p. 2581. , 1463-9076; Grimme, S., (2004) J. Comput. Chem., 25, p. 1463. , 0192-8651 10.1002/jcc.20078; Antony, J., Grimme, S., (2008) Phys. Chem. Chem. Phys., 10, p. 2722. , 1463-9076 10.1039/b718788b; Blochwitz, J., Pfeiffer, M., Fritz, T., Leo, K., (1998) Appl. Phys. Lett., 73, p. 729. , 0003-6951 10.1063/1.121982; Peumans, P., Forrest, S.R., (2001) Appl. Phys. Lett., 79, p. 126. , 0003-6951 10.1063/1.1384001; McKeown, N.B., (1998) Phthalocyanine Materials: Synthesis, Structure, and Function, , (Cambridge University Press, Cambridge); Warman, J.M., De Haas, M.P., Dicker, G., Grozema, F.C., Piris, J., Debije, M.G., (2004) Chem. Mater., 16, p. 4600. , 0897-4756 10.1021/cm049577w; Gorgoi, M., Michaelis, W., Kampen, T.U., Schlettwein, D., Zahn, D.R.T., (2004) Appl. Surf. Sci., 234, p. 138. , 0169-4332; Evangelista, F., Carravetta, V., Stefani, G., Jansik, B., Alagia, M., Stranges, S., Ruocco, A., (2007) J. Chem. Phys., 126, p. 124709. , 0021-9606 10.1063/1.2712435; Alfredsson, Y., Brena, B., Nilson, K., Åhlund, J., Kjeldgaard, L., Nyberg, M., Luo, Y., Siegbahn, H., (2005) J. Chem. Phys., 122, p. 214723. , 0021-9606 10.1063/1.1924539; Ekström, U., Norman, P., (2006) Phys. Rev. A, 74, p. 042722. , 1050-2947 10.1103/PhysRevA.74.042722; Ekström, U., Norman, P., Carravetta, V., Ågren, H., (2006) Phys. Rev. Lett., 97, p. 143001. , 0031-9007 10.1103/PhysRevLett.97.143001; Boyd, R.W., (2003) Nonlinear Optics, , 2nd ed. (Academic, New York); Norman, P., Bishop, D.M., Jensen, H.J.A., Oddershede, J., (2001) J. Chem. Phys., 115, p. 10323. , 0021-9606 10.1063/1.1415081; Norman, P., Bishop, D.M., Jensen, H.J.A., Oddershede, J., (2005) J. Chem. Phys., 123, p. 194103. , 0021-9606 10.1063/1.2107627; Jiemchooroj, A., Ekström, U., Norman, P., (2007) J. Chem. Phys., 127, p. 165104. , 0021-9606 10.1063/1.2800024; Jiemchooroj, A., Norman, P., (2008) J. Chem. Phys., 128, p. 234304. , 0021-9606 10.1063/1.2937906; Tu, G., Rinkevici