Nuclear quadrupole interaction of highly polarized gas phase 131Xe with a glass surface

Abstract

We report nuclear magnetic resonance (NMR) experiments on 131Xe (I=3/2) gas-phase atoms which exhibit nuclear quadrupole interaction with the surface of the sample cell. Nuclear quadrupole coupling constants and quadrupole relaxation rates are obtained from the time-domain signal of the freely precessing nuclear magnetization in weak magnetic fields. The nuclear spin species is polarized by spin-exchange collisions with optically pumped ground-state spins of Rb gas atoms. The Rb atoms also present in the sample are used as a magnetometer to probe the free-induction decay of the nuclear-spin ensemble. The temperature dependence of both the effective quadrupole splittings and the relaxation rates are explained by a model for the surface interactions of a Xe atom adsorbed on the glass surface. The desorption is thermally activated with an activation energy of EA=0.12 eV. The surface diffusion of an adsorbed atom is characterized by an activation energy ED for thermally activated hopping between neighboring surface sites. Both energies enter the spectral density function governing wall-induced nuclear quadrupole relaxation. Our experimental results lead to the conclusion that they are on the same order of magnitude.

A magnetic resonance study of non-adiabatic evolution of spin quantum states

“…The f-axis is parallel to the principal axis of an axially symmetric EFG tensor. The origin of this orientation of the f quantum axis lies in the fact that the nuclear quadrupole moment of the ~3~Xe atoms interact with the EFG on every surface element of the container's inner surface [25][26][27]. The ensemble-averaged quadrupole interaction results in an effective quadrupole Hamiltonian of the form Ho.…”

“…In the absence of rotations and in zero magnetic field the magnetization of the polarized pairwise doubly degenerate 46 Hz represents the zero-field nuclear quadrupole resonance (NQR) spectrum which allows the determination of the averaged quadrupole coupling constant for ~a tXe at the glass surface of the container [27]. Besides the oscillation an exponentially decaying offset towards the equilibrium state of the 131Xe polarization can be observed.…”

Detection of tobacco smoke deposition by hyperpolarized krypton-83 MRI

“…relaxation measured in NMR experiments is the average between surface-induced relaxation and the relaxation occurring during the long bulk gas-phase residence time [18,35]. The resulting T 1 times typically range between a few seconds and a few tens of seconds when the gas is contained in desiccated lung tissue or materials with similar surface-to-volume ratios.…”

Laser‐Assisted Magnetic Resonance: Principles and Applications

“…Increasing the spin polarization by optical pumping has significantly improved the sensitivity of this type of experiments. In particular the transfer of spin polarization from optically pumped alkali atoms to Xe nuclear spins [12] has allowed to study the effect of surfaces on the magnetic resonance spectrum [73,74]. For experiments with oriented surfaces, the use of light for optical pumping as well as for detection brings, apart from the sensitivity advantages, also the possibility to select signal contributions that originate from atoms that are close to the surface.…”