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

We identify the molecular ion NH^+ as a potential candidate for probingvariations in the fine structure constant alpha and electron-to-proton massratio mu. NH^+ has an anomalously low-lying excited Sigma state, being only afew hundred cm^-1 above the ground Pi state. Being a light molecule, thisproximity is such that rotational levels of the respective states are highlyintermixed for low angular momenta. We find that several low-frequencytransitions within the collective rotational spectrum experience enhancedsensitivity to alpha- and mu-variation. This is attributable to the closeproximity of the Pi and Sigma states, as well as the ensuing strong spin-orbitcoupling between them. Suggestions that NH^+ may exist in interstellar spaceand recent predictions that trapped-ion precision spectroscopy will beadaptable to molecular ions make NH^+ a promising system for futureastrophysical and laboratory studies of alpha- and mu-variation.

Rotational spectrum of molecular ion NH^+ as a probe for alpha- and m_e/m_p-variation