Toward efficient trace detection and characterization of diagonal radioactive molecular ions using a spectrally filtered broadband laser

Heavy, radioactive isotopes offer enhanced sensitivities to fundamental symmetry violations. The large internal electric fields of molecules not reproducible in a lab setting also offer enhanced sensitivity. Combined, radioactive molecules promise the capability to probe a diverse variety of sources of symmetry violations including an electron electric dipole moment (eEDM), nuclear Schiff moments (NSMs), and magnetic quadrupole moments (MQMs). Any of these sources of violations have profound implications for the existence of new physics if they are found to disagree with Standard Model predictions and may, for example, provide insight into the matter—antimatter asymmetry problem. 

Unfortunately, radioactive precursors are typically only available in micro- or even nano-gram quantities and require significant safety and hazard considerations. These constraints provide a considerable challenge to acquiring the requisite knowledge and statistics necessary for a precision measurement. Here, I propose using spectrally filtered broadband optical pumping and action spectroscopy to efficiently characterize trapped radioactive polyatomic molecular ions using only hundreds to thousands of radioactive molecules. This approach was demonstrated on the diagonal FCF SiO+[1,2]. I will discuss application of this approach to the recently theoretically considered diagonal FCF polyatomic ion candidates containing Ac-O [3] and Ra-N [4,5] bonds.

[1] Phys. Rev. Lett. 125, 113201

[2] Nat Commun 12, 2201 (2021)

[3] Phys. Rev. A 105, 022825

[4] Isaev, Timur, Dmitrii Makinskii, and Andrei Zaitsevskii. "Radium-containing molecular cations amenable for laser cooling." Chemical Physics Letters 807 (2022): 140078.

[4] Isaev, Timur, et al. "Optical cycling in charged complexes with Ra–N bonds." Chemical Physics Letters 845 (2024): 141301.