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

The practical limitations of fully lithium ion insertion and extraction into LiMn2O4 cathode structure without any structural instability make it unsuitable in commercial Li-ion rechargeable batteries In this work, we showed that those partially substituted by Ni, ie, LiMn2−xNixO4 (0≤x≤05), prepared by sol-gel technique, could be used as a potential candidate for high energy density and high voltage Li-ion battery applications with superior rate capabilities The improved structural stability of the cathode was probed by x-ray diffraction and micro-Raman spectroscopy The density-functional theoretical calculations were employed to identify the minimum energy needed for Li+ diffusion pathway and activation energy in the spinel framework with different Ni ion concentrations Our results showed significant enhancement in the properties with 25at% of Ni solid-solution doping in LiMn2O4 host and the experimental results are in line with the theoretical computations

Spinel LiMn2−xNixO4 cathode materials for high energy density lithium ion rechargeable batteries

Ab initio Monte Carlo simulated annealing method

Relativistic MR-MP calculations of the energy levels and transition probabilities in Ni- to Kr-like Pt ions

Accurate theoretical energy level, lifetime, and transition probability calculations of core-excited Fe XVI were performed employing the relativistic Multireference Moller-Plesset perturbation theory. In these computations the term energies of the highly excited n ≤ 5 states arising from the configuration 1s 22sk 2pm 3l p nl' q , where k + m + p + q = 9, l ≤ 3 and p + q ≤ 2 are considered, including those of the autoionizing levels with a hole-state in the L-shell. All even and odd parity states of sodium-like iron ion were included for a total of 1784 levels. Comparison of the calculated L-shell transition wavelengths with those from laboratory measurements shows excellent agreement. Therefore, our calculation may be used to predict the wavelengths of as of yet unobserved Fe XVI, such as the second strongest 2p-3d Fe XVI line, which has not been directly observed in the laboratory and which blends with one of the prominent Fe XVII lines.

HIGH-ACCURACY MR-MP PERTURBATION THEORY ENERGY AND RADIATIVE RATES CALCULATIONS FOR CORE-EXCITED TRANSITIONS IN Fe XVI

The theoretical study of CO adsorption and H 2 O dissociation on a series of mixed Pt-M surfaces [6,7,10] has provided a broad array of information necessary to understand the required characteristics of CO-tolerant binary catalysts. In addition some understanding of important steps in electrocatalytic reactions of small molecules has been gained. The growing awareness that enhanced catalytic activity is to be sought at the nanoscale level, rather than in bulk alloys, renders theoretical studies of reactions on small metal clusters especially significant.

Yasuyuki Ishikawa

Papers

Spinel LiMn2−xNixO4 cathode materials for high energy density lithium ion rechargeable batteries

Ab initio Monte Carlo simulated annealing method

Relativistic MR-MP calculations of the energy levels and transition probabilities in Ni- to Kr-like Pt ions

HIGH-ACCURACY MR-MP PERTURBATION THEORY ENERGY AND RADIATIVE RATES CALCULATIONS FOR CORE-EXCITED TRANSITIONS IN Fe XVI

Chapter 10 - A theory-guided design of bimetallic nanoparticle catalysts for fuel cell applications