English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

A benchmark ab initio and density functional (DFT) study has been carried outon the electron affinities of the first- and second-row atoms. The ab initiostudy involves basis sets of $spdfgh$ and $spdfghi$ quality, extrapolations tothe 1-particle basis set limit, and a combination of the CCSD(T), CCSDT, andfull CI electron correlation methods. Scalar relativistic and spin-orbitcoupling effects were taken into account. On average, the best ab initioresults agree to better than 0.001 eV with the most recent experimentalresults. Correcting for imperfections in the CCSD(T) method improves the meanabsolute error by an order of magnitude, while for accurate results on thesecond-row atoms inclusion of relativistic corrections is essential. The latterare significantly overestimated at the SCF level; for accurate spin-orbitsplitting constants of second-row atoms inclusion of (2s,2p) correlation isessential. In the DFT calculations it is found that results for the 1st-rowatoms are very sensitive to the exchange functional, while those for second-rowatoms are rather more sensitive to the correlation functional. While the LYPcorrelation functional works best for first-row atoms, its PW91 counterpartappears to be preferable for second-row atoms. Among ``pure DFT'' (nonhybrid)functionals, G96PW91 (Gill 1996 exchange combined with Perdew-Wang 1991correlation) puts in the best overall performance. The best results overall areobtained with the 1-parameter hybrid modified Perdew-Wang (mPW1) exchangefunctionals of Adamo and Barone [J. Chem. Phys. {\bf 108}, 664 (1998)], withmPW1LYP yielding the best results for first-row, and mPW1PW91 for second-rowatoms. Indications exist that a hybrid of the type $a$ mPW1LYP + $(1-a)$mPW1PW91 yields better results than either of the constituent functionals.Comment: Phys. Rev. A, in press (revised version, review of issues concerning  DFT and electron affinities added

Electron affinities of the first- and second-row atoms: Benchmarkab initioand density-functional calculations