The dimeric Zintl ion [Hg(2)(As(7))(2)](4-) has been synthesized with high crystalline yield from the reaction of an ethylendiamine solution of the intermetallic Zintl phase K(3)As(7) with diphenyl mercury. Single crystal X-ray diffraction of [K(2,2,2-crypt)](4)[Hg(2)As(14)], 1 (2,2,2-crypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane), reveals that the cluster anion exhibits a...

We point out that the zero-energy Landau level of Dirac fermions in graphene can be, in the presence of a repulsive electronelectron interaction, split into two associated with a “bond ordering” formation having a “Kekulé pattern”, which respects the chiral symmetry. Since the Kekulé pattern has a three-fold degeneracy, domain structures are implied, for which we show that in-gap states localiz...

We have theoretically investigated the effect of doping in oligothiophenes (Tn, n=2-8) with the DFT method at UB3LYP level with 6-31G(d) basis set. Our attention focused on the study of the geometrical and electronic properties in the neutral and doped states. We show that the doping process modify both bond lengths and torsion angles and also electronic properties by enhancing the planarity an...

We have performed density functional theory (DFT) calculations to investigate the properties of defect in arepresentative armchair model of silicon nanotubes (SiNTs). To this aim, the structures of pristine and defective(5,5) SiNTs have been optimized and the properties such as bond lengths, total energies, binding energies,.formation energies, gap energies, and dipole moments have been evaluat...

A hybrid Car-Parrinello QM/MM molecular dynamics simulation has been carried out for theWatson-Crick base pair of 9-ethyl-8-phenyladenine and 1-cyclohexyluracil in deuterochloroform solution at room temperature. The resulting trajectory is analyzed putting emphasis on the N-H· · ·N Hydrogen bond geometry. Using an empirical correlation between the N · · ·N-distance and the fundamental NH-stretc...

An ab initio computational study was performed for wurtzite CdSe nanorods over a range of diameters and cross-sectional topologies as a function of the types of terminating surface facets. Calculations show that hexagonal cross sections containing surface atoms with one dangling bond are highly stable, possessing a large electronic band gap and exhibiting minimal surface reorientation. It is al...

the monitoring and controlling of environmental pollutions are very important in biological and industrial processes, and a great interest is growing with the development of suitable gas–sensitive materials and hazardous chemical removal devices. in this work, the highly parameterized, empirical exchange–correlation functional m06–2x were employed to investigate the electronic sensitivity of pe...

Inelastic neutron scattering experiments on the S = 1 quasi-one-dimensional bond-alternating antiferromagnet Ni(C9D24N4)(NO2)ClO4 have been performed under magnetic fields below and above a critical field Hc at which the energy gap closes. Normal field dependence of Zeeman splitting of the excited triplet modes below Hc has been observed, but the highest mode is unusually small and smears out w...