Volume 122, Issue 3, 15 January 2005
Index of content:
122(2005); http://dx.doi.org/10.1063/1.1849158View Description Hide Description
We report on the morphological dynamics of surfacepatterns induced by swelling of metal-capped polymer bilayer on a substrate. When the bilayer is subject to solvent vapor, the strain is generated in the polymer layer that is confined by the substrate and the metal capping layer. An increase in the strain induces the development of the stress in the bilayer to deform the lower polymer layer perpendicularly to the surface of the bilayer. Isotropic surface wavepatterns results from the stress relaxation, the wave number of the patterns shows a characteristic temporal dependency on the swelling time, such that This temporal evolution accompanied by the morphological dynamics gives smaller value of the growth rate of the characteristic wavelength than that of the case of swelling of gel.
Ab initio-based intermolecular carbon–carbon pair potentials for polycyclic aromatic hydrocarbon clusters122(2005); http://dx.doi.org/10.1063/1.1845432View Description Hide Description
We derived the carbon–carbon pair potentials for polycyclic aromatic hydrocarbon(PAH) clusters, which exhibited a strikingly similar geometry to that of the two-layer graphite. The binding energy of PAH clusters ranging in size from the benzene dimer to the pyrene dimer obtained by ab initio calculations at the MP2 level was used to extract the pair potentials in the form of the Lennard-Jones and Exponential-6 functions. Identical binding energy and equilibrium interlayer distance were reproduced by these functions to those calculated by the ab initio method. The pair potentials for PAHs yield the same equilibrium C–C distance as the known pair potentials for graphite and fullerenes, but nearly twice the well depth because of the polarization of the C–H bond.
122(2005); http://dx.doi.org/10.1063/1.1849132View Description Hide Description
A new scheme is developed for efficient quantum mechanical calculation of total energy of protein based on a recently developed MFCC (molecular fractionation with conjugate caps) approach. In this scheme, the linear-scaling MFCC method is first applied to calculate total electron density of protein. The computed electron density is then employed for direct numerical integration in density functional theory(DFT) to yield total energy of protein, with the kinetic energy obtained by a proposed ansatz. Numerical studies are carried out to calculate torsional energies of two polypeptides using this approach and the energies are shown to be in good agreement with the corresponding full system DFT calculation.