Electrophilic terminal arsinidene-iron(0) complexes with a two-coordinated arsenic atom

The electrophilic arsinidene complexes 5 and 6 featuring a two-coordinated arsenic atom have been isolated as crystalline solids. Complex 5 readily reacts with an NHC nucleophile (IMe4) to give the Lewis adduct 7.

First-Principles Study of Arsenic Atom, Its Irons and Molecule

In the present work, we have performed the ground state energy calculations for arsenic atom, its ions and molecule using Hartree-Fock (HF) cluster approximation. The correlation effects in the HF calculations have been taken into account by considering the Møller-Plesset second order perturbation (MP2) and truncated form of Configurational Interaction (CI) that includes single, double, and quadruple excitations, also known as QCISD implemented by the Gaussian 03 sets of program. Our study shows that the ground state of arsenic atom is a quadrate state i.e., charge zero and multiplicity four with ground state energy - 60796.66 eV in MP2 levels of calculation with cc-pVDZ basis set. We have performed the first-principles calculation to study the first electron affinity and ionization energies of arsenic atom up to tenth level. The first-principles calculation has been also carried out to study the equilibrium configuration of arsenic molecule (As2). The bond length and binding energy of arsenic molecule (As2) is found to be 2.15 Å and 3.65 eV in MP2 levels of approximation with basis set 6-311G(3df). Our study has been extended to calculate electrostatic potential for arsenic molecule (As2), whose values at global maxima and minima are found to be 0.30 eV and - 0.20 eV respectively. The calculation of HOMO-LUMO energy gap for the arsenic molecule (As2) is almost independent of choice of basis sets as well as levels of approximation. The HF, MP2, and QCISD calculations also have been carried out to estimate the electric field gradient (EFG) parameters for the excited nuclear state in arsenic molecule (As2). Our results show that the HF, MP2, and QCISD values for the EFG parameters do not differ significantly, indicating that electron correlation effects do not contribute for the determination of EFG parameter.The Himalayan Physics Year 5, Vol. 5, Kartik 2071 (Nov 2014)Page : 17-21

Clustering of Arsenic Atoms in Silicon during Low-Temperature Annealing

Simulation of arsenic clustering in Si at a temperature of 750 degrees Celsius has been carried out. It has been shown that considering the formation of singly or doubly negatively charged clusters that incorporate one or two arsenic atoms and point defects, one obtains a good fit to the measured values of electron density. It is supposed that we have the initial stage of clustering, when the concentration of complexes with one arsenic atom incorporated is high enough and the diffusion of these mobile particles provides for the formation of more stable clusters incorporating two arsenic atoms.