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/

Zendy Plus

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

Zendy Tools

Zendy Open

We investigate Born-Oppenheimer breakdown (BOB) effects (beyond the usualmass scaling) for the electronic ground states of a series of homonuclear andheteronuclear alkali-metal diatoms, together with the Sr$_2$ and Yb$_2$diatomics. Several widely available electronic structure software packages areused to calculate the leading contributions to the total isotope shift forcommonly occurring isotopologs of each species. Computed quantities includediagonal Born-Oppenheimer corrections (mass shifts) and isotopic field shifts.Mass shifts dominate for light nuclei up to and including K, but field shiftscontribute significantly for Rb and Sr and are dominant for Yb. We compare the{\em ab initio} mass-shift functions for Li$_2$, LiK and LiRb withspectroscopically derived ground-state BOB functions from the literature. Wefind good agreement in the values of the functions for LiK and LiRb at theirequilibrium geometries, but significant disagreement with the shapes of thefunctions for all 3 systems. The differences may be due to contributions ofnonadiabatic terms to the empirical BOB functions. We present a semiclassicalmodel for the effect of BOB corrections on the binding energies ofnear-threshold states and the positions of zero-energy Feshbach resonances.

Deviations from Born-Oppenheimer mass scaling in spectroscopy and ultracold molecular physics