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The thermally softened and the mechanically stiffened graphene phonons have been formulated from the perspective of bond order-length-strength correlation with confirmation of the C-C bond length in the single-layer graphene contracting from 0.154 to 0.125 nm and the binding energy increasing from 0.65 to 1.04 eV. Matching theory to the measured temperature- and pressure-dependent Raman shift has derived that the Debye temperature drops from 2230 to 540 K, the atomic cohesive energy drops from 7.37 to 3.11 eV/atom, and the binding energy density increases from 250 to 320 eV/nm3 compared with the respective quantities of bulk diamond. [ABSTRACT FROM AUTHOR]

Although the size- and shape-induced blueshift in the photoluminescence and photoabsorption of nanostructured ZnO has been extensively investigated, the underlying mechanism remains yet unclear. Here we show that theoretical reproduction of the observed trends clarifies that the blueshift originates from the Hamiltonian perturbation due to the broken-bond-induced local strain and quantum trapping and electron-phonon coupling in the surface skin up to two atomic layers in depth while bonds in the core interior retain their bulk nature. The extent of the blue shift depends on the tunable fraction of undercoordinated atoms in the surface skin. Therefore, the quantum confinement effect is indeed more “superficial” than first thought [H. Winn, OE Mag. 8, 10 (2005)]. [ABSTRACT FROM AUTHOR]