X-ray Absorption Near Edge Structure [XANES] of FePt nanoclusters has been studied using a full multiple scattering, self-consistent field [SCF], real-space Green‘s function approach realized via the powerful ab initio FEFF8 code. One purpose of our study is to determine the sensitivity of Pt L3 edge with respect to the size and shape of the FePt nanoclusters. We also give the results of the ca...

Gas phase and aqueous phase quantum chemical calculations for the inhibition efficiency of some substituted Benzothiazole (BTH) and its 2-methyl (MeBTH), 2-amino (ABTH), 2-mercapto (MBTH) and 2-phenyl (PhBTH) as corrosion inhibitors for brass in HClO4 were investigated by means of the AM1, PM6, MNDO and RM1 semi-empirical SCF molecular orbital methods. The calculated quantum chemical parameters...

The EBO model, originally proposed by Lennard-Jones and Hall, many years ago, is reexamined using localized orbitals (LMO) stemming from SCF ab initio calculations. It is found that only a· limited set of matrix elements is needed to build a Fock matrix F, (in localized basis) the diagonalization of which yields orbital energies of sufficient precision for use in the assignment of photoelectron...

The analytic linear response formalism for the calculation of the effective contact densities ρ̅ in the context of the normalized elimination of the small component (NESC) method is developed and implemented. The formalism is tested for the calculation of contact densities and contact density differences in a series of mercury cations and mercury-containing molecules. The calculations carried ou...

We introduce error weighting functions into the perturbative Monte Carlo method for use with a hybrid ab initio quantum Ž . mechanicsrmolecular mechanics QMrMM potential. The perturbative Monte Carlo approach introduced earlier provides a means to reduce the number of full SCF calculations in simulations using a QMrMM potential by evoking perturbation theory to calculate energy changes due to d...

The regulated oscillation of protein expression is an essential mechanism of cell cycle control. The SCF class of E3 ubiquitin ligases is involved in this process by targeting cell cycle regulatory proteins for degradation by the proteasome, with the F-box subunit of the SCF specifically recruiting a given substrate to the SCF core. Here we identify NIPA (nuclear interaction partner of ALK) as ...

Calibration ab initio (direct coupled cluster) calculations including basis set extrapolation, relativistic effects, inner-shell correlation, and an anharmonic zero-point energy, predict the total atomization energy at 0 K of SO 3 to be 335.96 (observed 335.92±0.19) kcal/mol. Inner polarization functions make very large (40 kcal/mol with spd, 10 kcal/mol with spdf g basis sets) contributions to...

We report first principles density functional calculations for 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and several reduced forms. DHICA and 5,6-dihydroxyindole (DHI) are believed to be the basic building blocks of the eumelanins. Our results show that carboxylation has a significant effect on the physical properties of the molecules. In particular, the relative stabilities and the HOMOLUM...

EMPIRE is a massively parallel semiempirical (NDDO) molecular-orbital program designed to scale well both on single multi-core nodes (using open MP) and on large clusters (using a hybrid open MP/MPI model). The program design and performance are discussed for single self-consistent-field calculations on up to 76,800 atoms and on both singleand multi-node machines using either Windows 7 or Linux...