Electronic stress tensor analysis of hydrogenated palladium clusters

TL;DR

This paper uses electronic stress tensor analysis to classify chemical bonds in small hydrogenated palladium clusters, introducing a new bond order measure and the concept of pseudo-spindle structures.

Contribution

It presents a novel application of stress tensor-based bond orders to classify bonds and introduces the pseudo-spindle structure concept for analyzing Pd-H and H-H bonds.

Findings

Bond orders effectively classify different bond types.

Pd-H bonds vary with hydrogen coordination.

Pseudo-spindle structures characterize bonding regions.

Abstract

We study the chemical bonds of small palladium clusters Pd_n (n=2-9) saturated by hydrogen atoms using electronic stress tensor. Our calculation includes bond orders which are recently proposed based on the stress tensor. It is shown that our bond orders can classify the different types of chemical bonds in those clusters. In particular, we discuss Pd-H bonds associated with the H atoms with high coordination numbers and the difference of H-H bonds in the different Pd clusters from viewpoint of the electronic stress tensor. The notion of "pseudo-spindle structure" is proposed as the region between two atoms where the largest eigenvalue of the electronic stress tensor is negative and corresponding eigenvectors forming a pattern which connects them.