Electronic Structures of Small Stoichiometric ZnO Clusters.

Area of Science:

• Physical Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Stoichiometric zinc oxide (ZnO) clusters are known for their stability compared to nonstoichiometric forms.
• Previous studies utilized computational and mass spectrometry methods to investigate ZnO cluster stability.
• Subnanometer clusters present unique properties due to their size and stoichiometry.

Purpose of the Study:

• To experimentally determine the structures of stoichiometric ZnO clusters (x=2-5) using anion photoelectron spectroscopy.
• To computationally investigate the electronic states and stability of these ZnO clusters.
• To correlate experimental photoelectron spectra with theoretical calculations for structural elucidation.

Main Methods:

• Angle-resolved anion photoelectron (PE) spectroscopy was performed on stoichiometric ZnO- clusters (x=2-5).
• Computational studies including natural orbital ionization and detachment transition cross-section calculations were employed.
• Photoelectron angular distribution (PAD) analysis was used to validate theoretical structural models.

Main Results:

• Experimental spectra confirm Dnh ring structures for ZnO clusters (x=2-5) as predicted.
• A novel bent chain isomer was identified as the lowest energy structure for Zn2O2 anion and neutral.
• PADs generally agree with computed structures, except for Zn5O5-, suggesting vibronic coupling effects.

Conclusions:

• The study confirms the prevalence of stable ring structures in stoichiometric ZnO clusters.
• A new bent chain isomer for Zn2O2 provides insights into low-energy configurations.
• Properties of ring structures evolve smoothly with size, contrasting typical abrupt changes in small clusters.