Isotope Shifts in the Metastable a$^5$F and Excited y$^5$G$^\circ$ Terms of Atomic Titanium

TL;DR

This study measures isotope shifts in titanium's atomic transitions, revealing how nuclear and electronic structures influence these shifts, with implications for ultracold transition metal gases.

Contribution

It provides new measurements of isotope shifts in titanium's metastable and excited states, linking electronic and nuclear structure effects with high precision.

Findings

Resolved multiple isotope transitions in titanium vapor

Determined isotope-dependent variations in fine-structure splitting

Observed strong J-dependent variations in mass and field shifts

Abstract

We measure and analyze the isotope shifts the multiplet of transitions between the metastable a$^5$F and excited y$^5$G$^\circ$ terms of neutral titanium by probing a titanium vapor in a hollow cathode lamp using saturated absorption spectroscopy. We resolve the five $J\to J+1$ and the four $J\to J$ transitions within the multiplet for each of the the three $I=0$ stable isotopes ($^{46}$Ti, $^{48}$Ti, and $^{50}$Ti). The isotope shifts on these transitions allow us to determine the isotope-dependent variation in the fine-structure splitting of the a$^5$F and y$^5$G$^\circ$ levels themselves. Combined with existing knowledge of the nuclear charge radii of titanium nuclei, we derive the specific mass and field shifts, which arise from correlated electronic motion and electronic density at the nucleus respectively, and further observe a strong $J$-dependent variation in each. Our results yield insight into the electronic and nuclear structure of transition metal atoms like titanium, and also characterize optical transitions that may allow for optical manipulation of ultracold gases of transition metal species.