01943nas a2200229   4500008004100000022001400041245010800055210006900163260007600232300001400308490000800322520112100330653001401451653001401465653002301479653001901502653001801521653001401539100002001553700001801573856012201591       2011                        eng d  a0020-760800aAb initio calculations of the geometry and polarizabilities of bisphenyls having aliphatic substituents0 aAb initio calculations of the geometry and polarizabilities of b  aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcAPR  a1092-11000 v1113 a<p>Ab initio geometry optimization and polarizability calculations of a series of bisphenyls, which are the model compounds of chemically different polycarbonates using HF/6-31G and 6-31G** basis sets are presented. Calculated absolute value of the conformationally averaged optical anisotropy (<gamma(2)>) of diphenyl propane, a model analog of bisphenol A polycarbonate, is higher than the corresponding experimental value in the dilute solution phase. The calculations have reproduced the relative trend in the optical anisotropy for the different bisphenyl model compounds in a manner similar to those using semiclassical approach, by incorporation of the condensed phase polarizabilities and quantum chemically calculated geometry structure into the valence optical scheme. Individual contributions to the gas phase polarizability and optical anisotropy of the model compounds for various dihedral conformers, because of the presence of different aliphatic chemical groups, are correctly predicted by the calculations here. (C) 2010 Wiley Periodicals, Inc. Int J Quantum Chem 111: 1092-1100, 2011</gamma(2)></p>10aab initio10abisphenyl10aoptical anisotropy10apolarizability10aPolycarbonate10astructure1 aSulatha, M., S.1 aNatarajan, U.  uhttps://library.ncl.res.in/content/ab-initio-calculations-geometry-and-polarizabilities-bisphenyls-having-aliphatic-002058nas a2200157   4500008004100000022001400041245008700055210006900142260007100211300001400282490000800296520144200304100002001746700002301766856011101789       2011                        eng d  a1520-610600aEffect of chemical substituents on the structure of glassy diphenyl polycarbonates0 aEffect of chemical substituents on the structure of glassy diphe  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB  a1579-15890 v1153 a<p>Polycarbonates offer a wide variety of physical property behavior that is difficult to predict due to complexities at the molecular scale. Here, the physical structure of amorphous glassy polycarbonates having aliphatic and cycloaliphatic chemical groups is explored through atomistic simulations. The influence of chemical structure on solubility parameter, torsion distributions, radial distribution function, scattering structure factor; orientation distributions of phenylene rings and carbonate groups, and free volume distributions, leading to interchain packing effects, are shown. The effect of the cyclohexyl ring at the isopropylidene carbon as compared to the effect of the methyl groups positioned on the phenylene rings results in a larger reduction in the solubility parameter (delta). The interchain distance estimated for polycarbonates in this work is in the range of 5-5.8 angstrom. The o-methyl groups on the phenylene, rings, as compared to a cyclohexyl ring, lead to higher interchain distances. The highest interchain distance is observed with a trimethylcyclohexylidene group at the isopropylidene carbon. Atomistic simulations reveal two different types of packing arrangement of nearest neighbor chains in the glassy state, one type of which agrees with the NMR experimental data The fundamental insights provided here can be utilized for design of chemical structures for tailored macroscopic properties.</p>1 aSulatha, M., S.1 aNatarajan, Upendra  uhttps://library.ncl.res.in/content/effect-chemical-substituents-structure-glassy-diphenyl-polycarbonates-0