Electronic band structure is one of the most important intrinsic properties of a material, and is in particular crucial in electronic, photo-electronic and photo- catalytic applications. Kohn-Sham Density-functional theory (KS-DFT) within currently available local or semi-local approximations to the exchange-correlation energy functional is problematic for the description of electronic band structure. Many-body perturbation theory based on Green’s function (GF) provides a rigorous framework to describe excited-state properties of materials. The central ingredient of the GF-based many-body perturbation theory is the exchange- correlation self-energy, which accounts for all non-classical electron-electron interaction effects beyond the Hartree theory, and formally can be obtained by solving a set of complicated integro-differential equations, named Hedin’s equations. The
The constrained density functional theory (CDFT) was used to investigate the topological effects on intramolecular electron transfer processes that have been reported in previous experimental work [
In this paper, the interaction between hydrogen peroxide (HP) and water were systemically studied by atom-bond electronegativity equalization method fused into molecular mechanics (ABEEM/MM) and
We introduce a reaction model for use in coarse-grained simulations to study the chemical reactions in polymer systems at mesoscopic level. In this model, we employ an idea of reaction probability in control of the whole process of chemical reactions. This model has been successfully applied to the studies of surface initiated polymerization process and the network structure formation of typical epoxy resin systems. It can be further modified to study different kinds of chemical reactions at mesoscopic scale.
This review article addresses the widely used self-consistent field theory (SCFT) in interacting polymer systems. The theoretical framework and numerical method of solving the self-consistent equations are presented. In this paper, different structures of polymer can be considered, such as homopolymer, block copolymer, polydisperse polymer and charged polymer. Several systems, micro/macro phase separation, interface, self-assembly, are presented as examples to demonstrate its applications in details. Besides, the fluctuation effects are considered. The first order is Gaussian fluctuation theory, which can be used to determine the stability of the mean-field solution and predict the kinetics of unstable structure. The derivation and applications of Gaussian fluctuation theory are presented as well.
In this review the preparation methods of polymer nanoparticles from chemical microemulsion polymerization to physical methods such as spray-drying, freeze-drying, freeze-extracting, fast evaporation and spreading evaporation have been summarized. The influence of nanoconfinement on glass transition temperature (
Surface plasmon resonance (SPR) can provide a remarkably enhanced electromagetic field around metal surface. It is one of the enhancement models for explaining surface-enhanced Raman scattering (SERS) phonomenon. With the development of SERS theories and techniques, more and more studies referred to the configurations of the optical devices for coupling the excitation and radiation of SERS, including the prism-coupling, waveguide-coupling, and grating-coupling modes. In this review, we will summarize the recent experimental improvements on the surface plasmon-coupled SERS.
Well-aligned ZnO nanorod arrays were prepared on FTO substrate by hydrothermal method at low temperature for 5 h. The effect of ammonia on the length of ZnO nanorod was studied in detail. The resulting materials were extensively characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-visible absorption spectra (scatter mode). With the increase of ammonia, the length of ZnO nanorod increases.
Quantum chemistry calculations have been performed using Gaussian03 program to compute optimized geometry, harmonic vibrational frequency along with intensities in IR and Raman spectra at RHF/6-31++G** and B3LYP/6-31++G** levels for phenobarbitone (C12H12N2O3) in the ground state. The scaled harmonic vibrational frequencies have been compared with experimental FT-IR and FT-Raman spectra. Theoretical vibrational spectra of the title compound were interpreted by means of potential energy distributions (PEDs) using MOLVIB program. A detailed interpretation of the infrared spectra of the title compound is reported. On the basis of the agreement between the calculated and observed results, the assignments of fundamental vibrational modes of phenobarbitone were examined and some assignments were proposed. The theoretical spectrograms for FT-IR and FT-Raman spectra of the title compound have been constructed.