By making use of Janak’s interpolation in the Kohn-Sham method, together with an explicit and differentiable functional of the density for the exchange-correlation energy, like LDA or GGA, the second derivative of the energy with respect to the number of electrons, N, is evaluated from the derivative of the highest occupied molecular orbital (HOMO) with respect to N (left derivative), or from t...

A dyad (PI0-PIa) made of a linear (PI0) and an angular (PIa) perylene biscarboximide is synthesized and its spectroscopic, electrochemical and photophysical properties investigated in solvents of various polarity. PIa is characterized by a high intersystem crossing. The spectroscopy and electrochemistry data point to a modest electronic coupling. LUMO-LUMO electron transfer from the singlet exc...

We attempt to detect the possibility to modify the catalytic property of Pt/graphene using small organic molecule. Results of density functional theory calculations show that ssDNA segment and L-leucine modify the electron transfer at the interface, changing the electronic property and redox property of Pt/graphene catalyst system. L-leucine promotes electron transfer from Pt and increases the ...

Tuning the electronic band structures such as band-edge position and bandgap of organic semiconductors is crucial to maximize the performance of organic photovoltaic devices. We present a simple yet effective electron irradiation approach to tune the band structure of [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM) that is the most widely used organic acceptor material. We have found that th...

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...

With the aim of recognizing the steric effects on the silylenic R2C6H6Si structures, DFT calculationsare carried out on 8 structures of R2C6H6Si (where R is hydrogen (H), methyl (Me), isopropyl (i-pro),and tert-butyl (tert-Bu)). These species are at either triplet (t) or singlet (s) states. Singlet–tripletenergy separations ( Me (20.32) > t-Bu (15.92).all singlet states of R2C6H6Si, are more st...

Electronic and geometric structures of MxSy (M=W, Mo; x = 1, 2, 4; y = 1–12) clusters have been studied using density functional theory calculations, and compared to experimental photoelectron spectra. For the metal atoms, an uptake of up to six sulfur atoms has been observed, which can be explained by the bonding of S3 chains. A structural difference to the corresponding oxides is the preferen...

The electronic structure of ultrasmall Au clusters on thin MgO/Ag(001) films has been analyzed by scanning tunneling spectroscopy and density functional theory. The clusters exhibit two-dimensional quantum well states, whose shapes resemble the eigenstates of a 2D electron gas confined in a parabolic potential. From the symmetry of the highest occupied (HOMO) and lowest unoccupied molecular orb...

In mathematical chemistry, the median eigenvalues of the adjacency matrix of a molecular graph are strictly related to orbital energies and molecular orbitals. In this regard, the difference between the occupied orbital of highest energy (HOMO) and the unoccupied orbital of lowest energy (LUMO) has been investigated (see Fowler and Pisansky in Acta Chim. Slov. 57:513-517, 2010). Motivated by th...

In this work, we performed the design, synthesis, and the structure-activity relationship studies of 13 new derivatives of thieno[2,3-b]pyridine. These derivatives were prepared in high yields (96-70%) and their structures were elucidated by IR, (1)H, (13)C NMR, and MS. The biological results showed some derivatives as antiparasitic agents against Giardia lamblia. Computational analysis of HOMO...