# Comparative Study of Neutral and Cationic Sn2H2: Toward Laboratory Detection of the Cation

## TL;DR

This study compares the structures and properties of neutral and cationic tin hydride molecules to guide future laboratory detection of the cationic form.

## Contribution

The study provides the first CCSD(T) harmonic frequencies and CCSDT(Q)/CBS energies for Sn2H2 isomers and identifies the butterfly isomer as the global minimum.

## Key findings

- The butterfly isomer is the global minimum for both neutral and cationic Sn2H2.
- Seven minima and fifteen transition states were identified in the potential energy surface.
- Bond order changes between neutral and cationic species were analyzed using NBO.

## Abstract

Group 14 M2H2 isomers (M = Si,
Ge, Sn, and
Pb) have attracted interest due to their radically differing electronic
structures from acetylene. To better understand the Sn–H interactions
of the neutral and cationic Sn2H2 structures,
we present the most rigorous study of these systems to date. CCSD(T)/cc-pwCVTZ
harmonic frequencies are presented as the first predictions for the
neutral and cationic species to date. CCSDT(Q)/CBS relative energies
are reported using the focal point approach, confirming the butterfly
isomer as the global minimum on the potential energy surface for both
the neutral and cationic species. In all, there exist 7 minima and
15 transition states. NBO analysis is also performed to elucidate
the changes in bond order going from neutral to cation across all
isomers of Sn2H2. Our results provide insights
into the important Sn–H interaction and provide guidance for
future work that may detect in the laboratory for the first time.