Linear polyatomic molecules with \Pi\ ground state: sensitivity to variation of the fundamental constants

TL;DR

This paper investigates how the ro-vibrational spectra of linear polyatomic molecules with ab ground states, especially C3H, are highly sensitive to potential variations in fundamental constants like alpha and mu, due to the Renner-Teller effect.

Contribution

It highlights the enhanced sensitivity of certain molecular transition frequencies to fundamental constant variations caused by the Renner-Teller effect in linear polyatomic molecules.

Findings

Strong Renner-Teller interaction in C3H increases spectral sensitivity.

Low-lying vibronic ab level enhances transition frequency sensitivity.

Potential for using these molecules to detect variations in fundamental constants.

Abstract

In polyatomic molecules with \Pi\ electronic ground state the ro-vibrational spectrum can be strongly modified by the Renner-Teller effect. The linear form of C3H molecule has particularly strong Renner-Teller interaction and a very low lying vibronic \Sigma+ level, which corresponds to the excited bending vibrational mode. This leads to the increased sensitivities of the microwave and submillimeter transition frequencies to the possible variation of the fine structure constant alpha and electron to proton mass ratio mu.