Electronic State Chromatography of Lutetium Cations

TL;DR

This study developed an ion mobility spectrometer to measure and analyze the electronic state chromatography of lutetium cations, revealing how electronic states influence ion mobility in helium gas.

Contribution

The paper introduces a cryogenic drift tube spectrometer capable of distinguishing electronic states of heavy cations through ion mobility measurements.

Findings

Measured low-field reduced mobility of Lu+ in helium.

Demonstrated electronic state chromatography of Lu+.

Investigated mobility variation and quenching of meta-stable states.

Abstract

Relativistic effects strongly influence the electronic structures of the heaviest elements, thereby shaping their chemical and physical properties. Studying ion mobility within a noble gas environment reveals how the ion-neutral interactions depend on the ion's electronic configurations, thus providing an avenue for exploring these effects. An ion mobility spectrometer with a cryogenic drift tube was developed to precisely measure the low-field reduced mobility of heavy lanthanide and actinide cations. The apparatus was characterized by optimizing the bunching operation of ions with a miniature RF coulomb buncher and evaluating the chromatography performance of the drift tube operated with helium buffer gas at a temperature of 298K. Systematic ion mobility measurements of lutetium cations (Lu$^{+}$) drifting in helium gas were carried out as a case study. The electronic state chromatography of Lu$^{+}$ has been demonstrated. The low-field reduced ion mobility for the ground and lowest meta-stable state of Lu$^{+}$ have been examined. In addition, the variation of both states' reduced mobility and the quenching of meta-stable population has been investigated under different reduced electric fields ($E/n_0$), the ratio of an electric field to neutral gas number density.