Computational Insight into Diatomic Molecules as Probes to Measure the Variation of the Proton-to-electron Mass Ratio

Abstract

Astrophysical molecular spectroscopy is an important means of searching for new physics through probing the variation of the proton-to-electron mass ratio, μ. New molecular probes could provide tighter constraints on the variation of μ and better direction for theories of new physics. Here we summarize our previous paper for astronomers, highlighting the importance of accurate estimates of peak molecular abundance and temperature as well as spectral resolution and sensitivity of telescopes in different regions of the electromagnetic spectrum. While none of the 11 astrophysical diatomic molecules we investigated showed enhanced sensitive rovibronic transitions at observable intensities for astrophysical environments, we have gained a better understanding of the factors that contribute to high sensitivities. From our results, CN, CP, SiN and SiC have shown the most promise of all astrophysical diatomic molecules for further investigation, with further work currently being done on CN.

Full Spectroscopic Model and Trihybrid Experimental-Perturbative-Variational Line List for CN

“…In Syme et al (2019); Syme & McKemmish (2020a), we simulated a variation in the proton-to-electron mass ratio in diatomic molecules using spectroscopic models. We calculated the sensitivity of the transitions, K, in these diatomic molecules by matching the transitions on their id number in each simulation and using equation 2 with the matched transition frequencies using…”

“…CN is a molecule ubiquitous in astrochemistry that has been well studied experimentally and theoretically. CN shows initial promise as a potential molecular probe to constrain the variation of the proton-to-electron mass ratio (Syme et al 2019;Syme & McKemmish 2020a), however an energy spectroscopic model of CN -not currently available -is required to identify key transitions of enhanced sensitivity.…”