Relativistic Pseudopotentials: Their Development and Scope of Applications

Theoretical Chemistry, University of Cologne, Greinstrasse 4, 50939 Cologne, Germany.
Chemical Reviews (Impact Factor: 45.66). 09/2011; 112(1):403-80. DOI: 10.1021/cr2001383
Source: PubMed
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    ABSTRACT: A recently published correlated electron pseudopotentials (CEPPs) method has been adapted for application to the 3d-transition metals, and to include relativistic effects. New CEPPs are reported for the atoms Sc$-$Fe, constructed from atomic quantum chemical calculations that include an accurate description of correlated electrons. Dissociation energies, molecular geometries, and zero-point vibrational energies of small molecules are compared with all electron results, with all quantities evaluated using coupled cluster singles doubles and triples (CCSD(T)) calculations. The CEPPs give better results in the correlated-electron calculations than Hartree-Fock-based pseudopotentials available in the literature.
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    ABSTRACT: Pseudopotentials simulate the interaction of the valence-electron system with frozen atomic cores using radially nodeless pseudo-orbitals. This leads to computational simplifications absent in frozen-core all-electron calculations. It is argued here that applying density fitting allows for using essentially the same (reduced) auxiliary basis sets for the valence interaction in both pseudopotential and all-electron calculations. We furthermore show that reduced auxiliary basis sets may also be made use of for fitting core Coulomb and exchange operators beyond on-site matrix elements. This leads to efficient substitutes for pseudopotentials in frozen-core all-electron calculations. At some pilot examples (Au-n, HfO, RnF6), we demonstrate the possibility to systematically improve the accuracy of standard pseudopotential calculations with limited additional computational effort.
    Journal of Chemical Theory and Computation 09/2014; 10(9):3857-3862. DOI:10.1021/ct500581h · 5.31 Impact Factor
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    ABSTRACT: The current status of relativistic electronic structure theory for superheavy elements is reviewed. Recent developments in relativistic quantum theory have made it possible to obtain accurate electronic properties for the trans-actinide elements with the aim to predict their chemical and physical behaviour. The role of quantum electrodynamic effects beyond the no-virtual-pair approximation, which is usually neglected in relativistic molecular calculations, is discussed. Changes in periodic trends due to relativistic effects are outlined for the superheavy elements with nuclear charge . We also analyse the role of the negative energy states for the electronic stability of superheavy elements beyond the critical nuclear charge ( ), where the 1s state enters the negative energy continuum at .