# Trihydrogen Formation on Gold Nanoparticles in Strong Laser Fields

## TL;DR

This study shows how the shape of gold nanoparticles affects the formation of trihydrogen cations under intense laser fields, offering insights into nanoscale chemical reactions.

## Contribution

The paper introduces a method to spatially map trihydrogen cation formation on gold nanoparticles and reveals how nanoparticle morphology influences reaction efficiency.

## Key findings

- Faceted gold nanoparticles with sharp features enhance trihydrogen cation yields due to concentrated charge.
- Nanoparticle morphology modulates charge density and reaction efficiency under laser fields.
- Strong-field interactions at metal interfaces can drive nanoscale reactivity and photocatalysis.

## Abstract

The trihydrogen cation
(H3
+) plays
a central role in proton-transfer chemistry,
astrochemical pathways, and hydrogen plasma environments, acting as
a key indicator of ultrafast proton rearrangement. Although H3
+ formation has
been studied extensively in the gas phase, its surface-mediated generation
and its sensitivity to nanoparticle morphology remain largely unexplored.
Gold nanoparticles (AuNPs), which can localize surface charge and
sustain strong electric fields, offer an ideal platform to probe such
nonequilibrium reaction pathways. Using reaction nanoscopy, we spatially
map H3
+ production
on AuNPs exposed to intense femtosecond laser fields. By comparing
spherical and faceted nanoparticles, we demonstrate how morphology
modulates the charge density and governs the reaction efficiency.
We find that sharp features on faceted particles concentrate charge
more effectively, promoting molecular fragmentation and enabling proton
rearrangement and migration that enhance H3
+ yields. This work opens new directions
for exploiting strong-field interactions at metal interfaces to drive
nanoscale reactivity and photocatalysis.