The recently reported photoswitching of diarylethene derivative molecules bridging carbon nanotube (CNT) contacts is theoretically analyzed. The short lifetime of the lowest unoccupied molecular orbital (LUMO) indicates that neither the open nor closed form of the molecule can be photoexcited into a charge-neutral excited state for any appreciable length of time preventing photochromic ring ope...

the research in the short-chain organic -conjugated molecules has become one of the most interesting topics in the fields of chemistry. these compounds have become the most promising materials for the optoelectronic device technology. the use of low band gap materials is a viable method for better harvesting of the solar spectrum and increasing its efficiency. the control of the band gap of th...

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...

Inelastic electron process that leads to vibrational excitation has attracted much attention of since the conductivity of molecules bridging the electrodes is found to be strongly affected when they are vibrationally excited [1]. Considering that the conduction electrons passes through the electronic state crossing the Fermi level or hopping through the HOMO or LUMO state of the molecule, the e...

C-modified 7-deazaadenosines containing a diphenylacetylene moiety have been synthesised using cross-coupling approaches. The C-modified nucleosides exhibit remarkable fluorescence properties, including high quantum yields. Solvatochromic studies show a near linear correlation between the Stokes shift and solvent polarity which is indicative of intramolecular charge transfer. DFT calculations h...

Electron-transfer cross-reactions between neutral molecules and their radical cations spanning a wide range of structural type and intrinsic reactivity have been analyzed using classical Marcus theory. The principal factor found to govern intrinsic reactivity is the inner-shell bond reorganization energy. The HOMO-LUMO overlap of alkyl groups on reacting molecules is generally sufficient to pro...

The optical properties of Al nanostructures are investigated by means of time dependent density functional theory, considering chains of varying length and ladders/stripes of varying aspect ratio. The absorption spectra show redshifting for increasing length and aspect ratio. For the chains the absorption is dominated by HOMO → LUMO transitions, whereas ladders and stripes reveal more complex s...

We report an efficient and practical procedure for the synthesis of cholesterol containing unsymmetrical liquid crystals dimers. Liquid crystalline thermal properties were studied by POM, TGA, DSC, SAXS analysis. All final products (3a-d) presented crystal properties. The presence smectic (compounds 3a, 3b, 3d) chiral nematic (3 c) mesophases evidenced polarised optical microscopy (POM) further...

Density functional theory (DFT) calculations based on the BLYP-D4 and PBEh-3c composite methods were performed for investigating encapsulation mode of pentachlorophenol (PCP) inside cavity β-cyclodextrin (β-CD). Different quantum chemical parameters such as HOMO, LUMO, HOMO–LUMO gap calculated. Complexation energies computed at molecular level to provide insight into inclusion PCP β-CD cavity. ...

The non-classical KP(6)Mo(18)O(73) heteropolyanion has been studied by the density functional theory (DFT) method, and the calculated geometry compares well with the experimental one. In fully oxidized [KP(6)Mo(18)O(73)](7-) state, the d(xy)-orbitals centered at eight "belt" Mo sites in the lower part of the "basket" are the major contributors to the LUMO and LUMO+1, while the LUMO+2 orbital is...