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

High-precision results are reported for the energy levels of $2{^1S}$ and$2{^1P}$ states of the beryllium atom. Calculations are performed using fullycorrelated Gaussian basis sets and taking into account the relativistic,quantum electrodynamics (QED), and finite nuclear mass effects. Theoreticalpredictions for the ionization potential of the beryllium ground state$75\,192.699(7) \icm$ and the $2{^1P} \rightarrow 2{^1S}$ transition energy$42\,565.441(11) \icm$ are compared to the known but less accurate experimentalvalues. The accuracy of the four-electron computations approaches that achievedfor the three-electron atoms, which enables determination of the nuclear chargeradii and precision tests of QED.

Testing quantum electrodynamics in the lowest singlet states of beryllium atom