Precision spectroscopy of the molecular ion HD+: control of Zeeman shifts

TL;DR

This paper presents an ab initio calculation of magnetic field effects on the HD+ molecular ion, identifying transitions with minimal Zeeman shifts suitable for high-precision spectroscopy and fundamental physics tests.

Contribution

It provides a comprehensive theoretical analysis of Zeeman shifts in HD+ and identifies optimal transitions for precision measurements, advancing molecular spectroscopy capabilities.

Findings

Identified transitions with controllable or negligible Zeeman shifts.

HD+ can be used to determine the electron-to-nuclear mass ratio.

Potential for testing the time-independence of fundamental constants.

Abstract

Precision spectroscopy on cold molecules can potentially enable novel tests of fundamental laws of physics and alternative determination of some fundamental constants. Realizing this potential requires a thorough understanding of the systematic effects that shift the energy levels of molecules. We have performed a complete ab initio calculation of the magnetic field effects for a particular system, the heteronuclear molecular hydrogen ion HD+. Different spectroscopic schemes have been considered, and numerous transitions, all accessible by modern radiation sources and exhibiting well controllable or negligible Zeeman shift, have been found to exist. Thus, HD+ is a perspective candidate for determination of the ratio of electron-to-nuclear reduced mass, and for tests of its time-independence.