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Mariusz Klobukowski

Publications and source records attributed to Mariusz Klobukowski.

4 recordsLinked to original sources

Compact and efficient basis sets of s- and p-block elements for model core potential method.

We propose compact and efficient valence-function sets for s- and p-block elements from Li to Rn to appropriately describe valence correlation in model core potential (MCP) calculations. The basis sets are generated by a combination of split MCP valence orbitals and correlating contracted Gaussian-type functions in a segmented form. We provide three types of basis sets. They are referred to as MCP-dzp, MCP-tzp, and MCP-qzp, since they have the quality comparable with all-electron correlation consistent basis sets, cc-pVDZ, cc-pVTZ, and cc-pVQZ, respectively, for lighter atoms. MCP calculations with the present basis sets give atomic correlation energies in good agreement with all-electron calculations. The present MCP basis sets systematically improve physical properties in atomic and molecular systems in a series of MCP-dzp, MCP-tzp, and MCP-qzp. Ionization potentials and electron affinities of halogen atoms as well as molecular spectroscopic constants calculated by the best MCP set are in good agreement with experimental values.

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Improved model core potentials for the second- and third-row transition metals.

New nonrelativistic and scalar-relativistic pseudopotentials for the second- and third-row transition metals have been developed. These improved Model Core Potentials were used in calculations for a variety of transition metal complexes to test their ability to reproduce experimental structures and vibrational frequencies.

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Accurate ab initio pair potentials between helium and the heavier group 2 elements.

Interactions between the heavier Group 2 metals (Ca, Sr, and Ba) and helium were studied using the well-tempered model core potential method. Accurate pair potentials, calculated at the coupled-cluster level of theory with very large basis sets, were used in bound state calculations. Three bound rovibrational states were found for each complex. The pair-potential parameters were used to predict how each of the metal atoms would be solvated by a helium nanodroplet. The Ca atom is not fully solvated by the droplet and the interaction between the helium and the metal decreases from Ca to Ba. This agrees with the experimental observation that the spectra of these atoms in a nanodroplet are intermediate between the spectra of the free atoms and the spectra in liquid helium.

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Development of new pseudopotential methods: improved model core potentials for the first-row transition metals.

We have recently developed new nonrelativistic and scalar-relativistic pseudopotentials for the first-row transition metal and several main-group elements. These improved Model Core Potentials were tested on a variety of transition metal complexes to determine their accuracy in reproducing electronic structures, bond lengths, and harmonic vibrational frequencies with respect to both all-electron reference data as well as experimental data. The new potentials are also compared with the previous model core potentials available for the first-row transition metals. The new potentials do a superior job at reproducing atomic data, reproduce molecular data as well as the previous version, and in conjunction with new main-group pseudopotentials that have L-shell structure of the valence basis set, they are slightly faster.

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