The Trapping and Characterization of a Single Hydrogen Molecule in a Continuously Tunable Nanocavity

TL;DR

This study uses STM-IETS and DFT to trap and analyze a single hydrogen molecule in tunable nanocavities, revealing how cavity shape influences molecular bonding and dissociation, advancing nanoscale chemical manipulation.

Contribution

It demonstrates the controlled trapping and characterization of a single H2 molecule in tunable nanocavities, showing cavity-dependent bond behavior and potential for chemical bond manipulation.

Findings

H2 bond length expands in atop cavity

Dissociation tendency increases as gap closes

Different cavity shapes affect H2 adsorption behavior

Abstract

Using inelastic electron tunneling spectroscopy with the scanning tunneling microscope (STM-IETS) and density functional theory calculations (DFT), we investigated properties of a single H2 molecule trapped in nanocavities with controlled shape and separation between the STM tip and the Au (110) surface. The STM tip not only serves for the purpose of characterization, but also is directly involved in modification of chemical environment of molecule. The bond length of H2 expands in the atop cavity, with a tendency of dissociation when the gap closes, whereas it remains unchanged in the trough cavity. The availability of two substantially different cavities in the same setup allows understanding of H2 adsorption on noble metal surfaces and sets a path for manipulating a single chemical bond by design.