Quantum State-Resolved Characterization of a Magnetically Focused Beam of ortho-H₂O

Abstract

Magnetic focusing of a molecular beam formed from a rotationally-cooled supersonic jet of H 2 O seeded in argon is shown to yield water vapour highly enriched in the ortho-H 2 O nuclear spin isomer (NSI). Rotationally-resolved resonance-enhanced multi-photon ionisation time-of-flight mass spectrometry demonstrates this methodology enables the preparation of a beam of water molecules enriched to >98 % in the ortho-H 2 O NSI, that is having an ortho-to-para ratio (OPR) in excess of 50:1. The flux and quantum-state purity achieved through the methodology described herein could enable heterogeneous chemistry applications including the preparation of a nuclear spin-polarized water adlayers, making nuclear magnetic resonance investigations amenable to surface science studies, as well as laboratory investigations of NSI interconversion mechanisms and rates in ice and at its surface.

Spin Hyperpolarization in Modern Magnetic Resonance

“…However, in contrast to NSIM of H 2 , NSIM of symmetric polyatomic molecules are not easily accessible, but could be of major interest for expanding the range of available sources of nuclear hyperpolarization in the experiments similar to those performed with parahydrogen (sections 3.11.2, 3.11.3, and 3.11.4). Successful separation of ortho-and parawater has been achieved in cold molecular beams using the gradient of a magnetic field (the Zeeman effect), 124 and was later extended to acetylene and methane. 125 Ortho-and parawater separation was also successfully achieved in cold molecular beams using the gradient of an electric field 109 (the Stark effect) (Figure 10).…”

Open-source, partially 3D-printed, high-pressure (50-bar) liquid-nitrogen-cooled parahydrogen generator

“…Nuclear magnetic resonance (NMR) as well as magnetic resonance imaging (MRI) are widely used in medical imaging and chemical analysis. Despite the great success of these techniques (Feyter et al, 2018;Lange et al, 2008;Watson et al, 2020), the low signal-to-noise ratio of NMR limits promising applications such as in vivo spectroscopy or imaging of nuclei other than 1 H (Wilferth et al, 2020;Xu et al, 2008). The hyperpolarization of nuclear spins boosts the signal of selected molecules by orders of magnitude.…”