Distinction of Nuclear Spin States with the Scanning Tunneling Microscope

TL;DR

This paper demonstrates nuclear spin state identification of hydrogen isotopes using scanning tunneling microscopy, achieving high spatial resolution and confirming the characteristic excitation energies related to nuclear spin states.

Contribution

The study introduces a method for nuclear spin state detection with STM, providing unprecedented spatial resolution and direct identification of para and ortho hydrogen isotopes.

Findings

Excitation energies match gas phase values

Nuclear spin states distinguished at nanoscale

Method confirms expected scaling with moment of inertia

Abstract

We demonstrate rotational excitation spectroscopy with the scanning tunneling microscope for physisorbed hydrogen and its isotopes hydrogen-deuterid and deuterium. The observed excitation energies are very close to the gas phase values and show the expected scaling with moment of inertia. Since these energies are characteristic for the molecular nuclear spin states we are able to identify the para and ortho species of hydrogen and deuterium, respectively. We thereby demonstrate nuclear spin sensitivity with unprecedented spatial resolution.