# Structural and Electronic Stabilization Tuning of Al6N6 Clusters via Hydrogenation: A Theory Study of Al6N6H8

## TL;DR

This study explores how adding hydrogen to Al6N6 clusters changes their structure and stability, using theoretical calculations to guide future experiments.

## Contribution

The paper reveals how hydrogenation transforms the structure and electronic properties of Al6N6 clusters, enhancing their stability.

## Key findings

- Hydrogenation transforms the Al6N6 cluster from a hexagonal prism to a cuboid structure.
- The HOMO–LUMO gap increases by 1.85 eV, indicating improved stability.
- Hydrogen substitution with other atoms or groups can further tune the cluster properties.

## Abstract

Investigating aluminum nitride (AlN) clusters is essential for understanding the properties of bulk AlN materials. The incorporation of hydrogen into AlN clusters represents an effective strategy for structural modification and for tuning their physicochemical properties. In this work, we conducted density functional theory (DFT) calculations on the dynamically stable global-minimum (GM) structure of Al6N6H8. Compared to the precursor Al6N6 cluster, the incorporation of eight hydrogen atoms achieves coordination saturation of all aluminum and nitrogen atoms, inducing a structural transformation from a hexagonal prism with D3d symmetry to a cuboid structure with D2h symmetry. The HOMO–LUMO gap of the Al6N6H8 cluster is increased by 1.85 eV compared to that of Al6N6, indicating a remarkable enhancement in stability. Chemical bonding and natural bond orbital (NBO) charge analyses reveal that the Al–N, Al–H, and N–H bonds are predominantly covalent single bonds, with a degree of ionicity arising from electronegativity differences. The hydrogen atoms bonded to Al and N can be substituted with a series of other atoms or functional groups, thereby further tuning the structures and properties of the clusters. To facilitate future experimental characterization, the infrared spectrum of Al6N6H8 was calculated, which shows an overall blue shift in the Al–N bond’s bending and stretching vibrations compared to those in the Al6N6 cluster.