Collisional $^{3}$He and $^{129}$Xe frequency shifts in Rb--noble-gas mixtures

TL;DR

This paper measures the enhancement factor for Rb-$^{129}$Xe collisions, enabling precise $^{129}$Xe polarimetry without needing a thermal-equilibrium NMR reference.

Contribution

The study provides the first high-pressure limit measurement of the Rb-$^{129}$Xe enhancement factor, expanding the understanding of collisional frequency shifts in noble-gas mixtures.

Findings

Measured $oldsymbol{\kappa_{0}}$ for Rb-$^{129}$Xe as 493±31.

Confirmed the high-pressure limit behavior of frequency shifts.

Enabled accurate $^{129}$Xe polarimetry without thermal-equilibrium NMR reference.

Abstract

The Fermi-contact interaction that characterizes collisional spin exchange of a noble gas with an alkali-metal vapor also gives rise to NMR and EPR frequency shifts of the noble-gas nucleus and the alkali-metal atom, respectively. We have measured the enhancement factor $\kappa_{0}$ that characterizes these shifts for Rb-$^{129}$Xe in the high-pressure limit to be 493$\pm$31, making use of the previously measured value of $\kappa_{0}$ for Rb-$^{3}$He. This result allows accurate $^{129}$Xe polarimetry with no need to reference a thermal-equilibrium NMR signal.