Ab initio effective core potentials (ECP’s) have been generated to replace the Coulomb, exchange, and core‐orthogonality effects of the chemically inert core electron in the transition metal atoms Sc to Hg. For the second and third transition series relative ECP’s have been generated which also incorporate the mass–velocity and Darwin relativistic effects into the potential. The ab initio ECP’s should facilitate valence electron calculations on molecules containing transition‐metal atoms with accuracies approaching all‐electron calculations at a fraction of the computational cost. Analytic fits to the potentials are presented for use in multicenter integral evaluation. Gaussian orbital valence basis sets are developed for the (3d,4s,4p), (4d,5s,5p), and (5d,6s,6p) orbitals of the first, second, and third transition series atoms, respectively. All‐electron and valence‐electron atomic excitation energies are also compared for the low‐lying states of Sc–Hg, and the valence‐electron calculations are found to reproduce the all‐electron excitation energies (typically within a few tenths of an eV).

Ab initio effective core potentials for molecular calculations. Potentials for the transition metal atoms Sc to Hg

Nitrogen (N)-doped carbon materials exhibit high electrocatalytic activity for the oxygen reduction reaction (ORR), which is essential for several renewable energy systems. However, the ORR active site (or sites) is unclear, which retards further developments of high-performance catalysts. Here, we characterized the ORR active site by using newly designed graphite (highly oriented pyrolitic graphite) model catalysts with well-defined π conjugation and well-controlled doping of N species. The ORR active site is created by pyridinic N. Carbon dioxide adsorption experiments indicated that pyridinic N also creates Lewis basic sites. The specific activities per pyridinic N in the HOPG model catalysts are comparable with those of N-doped graphene powder catalysts. Thus, the ORR active sites in N-doped carbon materials are carbon atoms with Lewis basicity next to pyridinic N.

Active sites of nitrogen-doped carbon materials for oxygen reduction reaction clarified using model catalysts

Today, coupled-cluster theory offers the most accurate results among the practical ab initio electronic-structure theories applicable to moderate-sized molecules. Though it was originally proposed for problems in physics, it has seen its greatest development in chemistry, enabling an extensive range of applications to molecular structure, excited states, properties, and all kinds of spectroscopy. In this review, the essential aspects of the theory are explained and illustrated with informative numerical results.

/pdf/coupled-cluster-theory-in-quantum-chemistry-nnwxwp80ej.pdf

Coupled-cluster theory in quantum chemistry

Physical Review B

https://courses.washington.edu/cfr523/documents/Alonso2010CatalyticConversion.pdf

Catalytic conversion of biomass to biofuels

Effect of base mismatch on the electronic properties of DNA–DNA and LNA–DNA double strands: Density-functional theoretical calculations

Second-order multiconfigurational Dirac–Fock self-consistent field and multireference configuration interaction calculations on beryllium and beryllium-like Ne6+

The electric-dipole $5s\text{\ensuremath{-}}5p$ resonance transitions in highly ionized promethiumlike ions have been studied applying relativistic multireference M\o{}ller-Plesset second-order perturbation theory. The transition wavelengths are determined to within 0.2 \AA{} in the more highly charged ions, where the level degeneracies are small. For somewhat lighter ions a very large reference space was used in order to account for the many degeneracies. In order to calculate transition probabilities and lifetimes, correlation corrections have been added to the transition operator in the next order. The contributions from the higher orders of the theory\char22{}that is, frequency-dependent Breit correction, Lamb shift, and mass shifts\char22{}have been estimated. The results are used to reassess spectroscopic data from beam-foil, electron-beam ion-trap, and tokamak observations.

/pdf/electric-dipole-5-s-5-p-transitions-in-promethiumlike-ions-3i79l5ao89.pdf

Electric-dipole 5 s − 5 p transitions in promethiumlike ions

We have studied the hydrogen oxidation reaction on various catalytic sites at the water/Pt(100) interface with first-principles direct molecular dynamics and minimum energy pathway calculations. The calculations indicate that the mechanism for electro-oxidation of H2 on terrace sites of the Pt(100) surface depends on the concentration of inactive adsorbed hydrogen on the electrode surface. Near the reversible potential, the electro-oxidation follows the Tafel-Volmer homolytic cleavage of H2 at low coverage of adsorbed hydrogen. If the surface is covered with ca. 1 monolayer of hydrogen, however, the oxidation proceeds by the Heyrovsky-Volmer mechanism. We found good agreement between measured and predicted Tafel plots, indicating that hydrogen oxidation/reduction reaction on Pt(100) takes place via the Heyrovsky-Volmer mechanism under ca. 1 monolayer coverage of inactive adsorbed hydrogen.

/pdf/electrochemical-hydrogen-oxidation-on-pt-100-a-combined-1vlbwetd6m.pdf

Electrochemical Hydrogen Oxidation on Pt(100): a Combined Direct Molecular Dynamics/Density Functional Theory Study

Accurate theoretical term energy separations of a number of even- and odd-parity excited states of siliconlike Fe and Kr ions are computed by a newly developed computational method in the framework of relativistic multireference many-body perturbation theory. Theory deviates from the CHIANTI atomic database by of the order of 0.01% for all but a few of the excited levels including the 3s33p3d 3F2,3,4o levels in siliconlike Fe (Fe12+). For the 3F2,3,4o levels of Fe12+, our results agree well with a recent experiment. Theoretical decay rates and lifetimes of the 3s23p3d 3F4o states of siliconlike Ar, Fe and Kr are evaluated.

Yasuyuki Ishikawa

Papers

Effect of base mismatch on the electronic properties of DNA–DNA and LNA–DNA double strands: Density-functional theoretical calculations

Second-order multiconfigurational Dirac–Fock self-consistent field and multireference configuration interaction calculations on beryllium and beryllium-like Ne6+

Electric-dipole 5 s − 5 p transitions in promethiumlike ions

Electrochemical Hydrogen Oxidation on Pt(100): a Combined Direct Molecular Dynamics/Density Functional Theory Study

Relativistic multireference many-body perturbation theory calculations for siliconlike argon, iron and krypton ions