Self-assembled-monolayers (SAMs) of aromatic thiolates on metal surfaces are candidates for molecular “quantum dots” or “wires”. We probe the interfacial electronic structure using two-photon photoemission in SAMs of pentafluorothiophenolate (C6F5S) on Cu(111). Compared to gas-phase C6F5SH, the σ* LUMO in the assembled molecule is stabilized by 3.1 eV and the HOMO-LUMO gap is reduced by 5.7 eV....

In this work, the effects of As-doped on the adsorption of oxygen gas on the outer and inner surface ofboron nitride nanotube (BNNTs) is investigated. The structural parameters, quantum properties involving:bond length, bond angle, HOMO-LUMO orbital, gapenergy, electron affinity, electronegativity, chemicalpotential, global hardness, global softness and NMR parameters of BNNTs are calculated at...

The difference between oxide and hydrogen passivation of small Si nanocrystals is explored by all-electron, hybrid functional DFT calculations with unrestricted geometry optimization. Oxide passivation lowers the band gap by about 2.4 eV for Si35 cores and by about 1.5 eV for Si66 cores. The oxide-passivated nanocrystals have optically forbidden, indirect-gap-type transitions whereas the hydrog...

The polarizability and second hyperpolarizability of fulvene, dimethylene-cyclobutene, trimethylene-cyclopropane, bicyclopentadiene-propane, bicyclopentadiene-propene, Dewar benzene, benzvalene and several of their anions are computed, employing a CNDO coupled Hartree-Fock procedure. The interaction of the lone pair on the anionic center with double and single bonds, the HOMO-LUMO gap, and subs...

Two Pt-H vibrational bands at 1679 cm(-1) and 1392 cm(-1) observed with 13-atom Pt clusters supported in LTL zeolite by Fourier Transform Infrared (FTIR) spectroscopy confirms that H atoms bridge two Pt atoms across the edges of the metal cluster. An additional broad absorption band centred near 2200 cm(-1) which exhibits some substructure is assigned to low energy electronic excitations across...

At the present theoretical study, DFT calculations were performed for elucidating thereaction, absorption energy and the quantum molecular descriptors including electronic chemical potential, chemical hardness, Homo, Lumo, band gap energy (Eg) and finding the most active nitrogen-doped graphene sheet (N-G) for absorption H2S, CH4, N2 and CO2 gases. Finally it found that nitrogen-doped gra...

Early pharmacological studies of Aconitum and Delphinium sp. alkaloids suggested that these neurotoxins act at site 2 of voltage-gated Na(+) channel and allosterically modulate its function. Understanding structural requirements for these compounds to exhibit binding activity at voltage-gated Na(+) channel has been important in various fields. This paper reports quantum-chemical studies and qua...

We investigated the electronic properties of N(5)-ethyl flavinium perchlorate (Et-Fl(+)) and compared them to those of its parent compound, 3-methyllumiflavin (Fl). Absorption and fluorescence spectra of Fl and Et-Fl(+) exhibit similar spectral features, but the absorption energy of Et-Fl(+) is substantially lower than that of Fl. We calculated the absorption signatures of Fl and Et-Fl(+) using...

We studied the adsorption of 4,4'-dithiodipyridine (PySSPy) on Au(111) under ultra-high vacuum conditions and at low-temperature both experimentally by means of scanning tunneling microscopy and spectroscopy (STM and STS), and theoretically by density functional theory (DFT). We find PySSPy molecules – characterized by their elongated appearance in STM – assembled in islands which reside exclus...

The Density Functional Theory (DFT) and the Natural Bond Orbital (NBO) calculations basedmethod B3LYP/6-31G were carried out to study the interaction of Dopamine with carbon nanotube.The nanotube used in this study, includes 60 C atoms (6, 6) type. Relative and formation energies ofcompounds, Muliken charges, occupancy, the highest occupied molecular orbital (HOMO) and thelowest unoccupied mole...