The energy position of the lowest unoccupied molecular orbital (LUMO) in 3,4,9,10-perylene-tetracarboxylic dianhydride (PTCDA) and dimethyl-3,4,9,10-perylenetetracarboxilic diimide (DiMePTCDI) was determined by investigating the energy level alignment at molecular semiconductor/GaAs(100) interfaces. Interface dipoles are found to form at the interfaces of both organic materials and consequently...

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 ...

We study Ge2O2 and Ge2O2 2 with density functional theory ~DFT! and photoelectron spectroscopy ~PES!. We find that Ge2O2 is a rhombus ~D2h), closed-shell molecule with a large HOMO-LUMO gap. The PES spectrum of Ge2O2 2 is obtained at four detachment photon energies: 1064, 532, 355, and 266 nm. Vibrational structure is resolved at the lowest photon energy with a single progression and a frequenc...

A detailed study of energy differences between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gaps) in protein systems and water clusters is presented. Recent work questioning the applicability of Kohn-Sham density-functional theory to proteins and large water clusters (Rudberg 2012 J. Phys.: Condens. Matter 24 072202) has demonstrated vanishing HOMO-LUMO gaps for thes...

Benzyl chloride and tin powder were used to prepare dibenzyltin dichloride according to a literatureprocedure. In this study, IR spectroscopy, HOMO-LUMO energy gap, NBO analysis, polarizability,some geometrical parameters, natural charge and electrical potential of atoms, global hardness,electronic chemical potential, global electrophilicity index, and molar volume of dibenzyltindichloride were...

Charge transport is studied in single-molecule junctions formed with a 1,7-pyrrolidine-substituted 3,4,9,10-perylenetetracarboxylic diimide (PTCDI) molecular block using an electrochemical gate. Compared to an unsubstituted-PTCDI block, spectroscopic and electrochemical measurements indicate a reduction in the highest occupied (HOMO)-lowest unoccupied (LUMO) molecular orbital energy gap associa...

The extended SSH model and Bogoliubov-de Gennes(BdeG) formalism are applied to investigate the electronic properties and stable lattice configurations of C36. We focus the problem on the molecule’s unusual D6h symmetry. The electronic part of the Hamiltonian without Coulomb interaction is solved analytically. We find that the gap between HOMO and LUMO is small due to the long distance hopping b...

In this paper and in order to guide the synthesis of novels materials with low band gaps, Theoretical study by using DFT method on six conjugated compound containing based on thiadiazolothienopyazine is reported. Different electron side groups were introduced to investigate their effects on the electronic structure. The theoretical knowledge of the HOMO and LUMO energy levels of the components ...

We investigate the electronic structure of the fullerenes encapsulated inside carbon nanotubes, the so-called nanopeapods, using the first-principles study. The orbital hybridization of LUMO+1 (the state above the lowest unoccupied molecular orbital) of C60, rather than LUMO as previously proposed, with the nanotube states explains the peak at approximately 1 eV in recent scanning-tunneling-spe...