We propose a third-order time-dependent perturbation theory approach to describe the chemical surfaceenhanced Raman spectroscopy of molecules interacting with two-dimensional (2D) surfaces such as an ideal 2D metal and graphene, which are both 2D metallic monolayers. A detailed analysis is performed for all the possible scattering processes involving both electrons and holes and considering the...

to investigation non-bonded interaction of the [cuf4]2- complex inside nanoring, we focus on the single wall boron-nitride b18n18 nanoring. thus, the geometry of b18n18 nanoring has been optimized by b3lyp method with epr-ii basis set and geometry of the [cuf4]2- complex has been optimized at b3lyp method with def2-tzvp basis set and stuttgart rsc 1997 effective core potential. also electronic ...

the density of state and the natural bond orbital calculations were carried out to study theoxidation of co on au14 nano cluster through two different mechanisms and determining the bestmechanism for the reaction. chemisorption of o2 and co on the nano cluster led to change in energy,density of state and its thermodynamic properties. we calculated the energy band gap between thehighest occupied...

Several nonradiative processes compete with tryptophan fluorescence emission. The difficulty in spectral interpretation lies in associating specific molecular environmental features with these processes and thereby utilizing the fluorescence spectral data to identify the local environment of tryptophan. Here, spectroscopic and molecular modeling study of Lys-Trp dipeptide charged species shows ...

We propose a series of icosahedral matryoshka clusters of A@B12@A20 (A = Sn, Pb; B = Mg, Zn, Cd), which possess large HOMO-LUMO gaps (1.29 to 1.54 eV) and low formation energies (0.06 to 0.21 eV/atom). A global minimum search using a genetic algorithm and density functional theory calculations confirms that such onion-like three-shell structures are the ground states for these A21B12 binary clu...

The FT-IR (4000-400 cm) and FTRaman (4000-100 cm) spectra of 2-chloro-4-nitroaniline (2Cl4NA) have been recorded using Bruker IFS 66 V spectrometer. An ab initio HF(HF/6-311G(d,p) and DFT(B3LYP/6-311G(d,p)) calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies,IR intensities and Raman activities. The study is extended to the HOMO LUMO analysis ...

Using an ab initio molecular-dynamics scheme ~the ‘‘fireball’’ scheme!, we determined the equilibrium structure of intermediate-size SinGem (n1m571) nanoclusters with and without hydrogen passivation on the surface. Due to the strong surface distortion, defect states are found to permeate the energy gap of SinGem clusters. However, the defect states are removed by adding H atoms on the surface ...

Phenyleneethynylene-based conjugated copolymers using benzo[1,2-d:4,5-d']bis[1,3]dioxole (BDO) in the repeating unit are reported. The electronic structure of the BDO unit imparts a localized HOMO topology while the LUMO is delocalized over the polymer backbone, so that the lowest optical absorption band of the polymer has considerable intramolecular charge transfer character. This contrasts wi...

C59-X (X= C, N, P, As and Sb) was studied by Density Functional Theory DFT at the B3LYP/3-21G** level. Group V elements have been selected to be substituted in the fullerene-C60 cage in order to show the effect of such substations upon structural and electronic properties of the studied molecules. It is found that elements of Group V doped C60 have an electronic structure similar to those of n-...