Photoelectron Velocity Map Imaging Spectroscopy of the Beryllium Trimer and Tetramer

• Type of Material: Article
• Authors: Noah Jaffe, Emory University; John F. Stanton, University of Florida, Gainesville; Michael Heaven, Emory University
• Language: English
• Date: 2023-09-12
• Publisher: American Chemical Society
• Publication Version: Final Published Version
• Copyright Statement: © 2023 The Authors. Published by American Chemical Society
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): https://doi.org/10.1021%2Facs.jpclett.3c02169
• Title of Journal or Parent Work: The Journal of Physical Chemistry Letters
• Volume: 14
• Issue: 37
• Start Page: 8339
• End Page: 8344
• Grant/Funding Information: The authors acknowledge the support of the U.S. Department of Energy, Office of Basic Energy Sciences under award DE-SC0018163 and the National Science Foundation under grant CHE- 2055579.
• Keywords: quantum chemistry; photodetachment spectra
• Research Categories: Chemistry, Physical

Abstract

Computational studies of small beryllium clusters (BeN) predict dramatic, nonmonotonic changes in the bonding mechanisms and per-atom cohesion energies with increasing N. To date, experimental tests of these quantum chemistry models are lacking for all but the Be2 molecule. In the present study, we report spectroscopic data for Be3 and Be4 obtained via anion photodetachment spectroscopy. The trimer is predicted to have D3h symmetric equilibrium structures for both the neutral molecule and the anion. Photodetachment spectra reveal transitions that originate from the X2A2″ ground state and the 12A1′ electronically excited state. The state symmetries were assigned on the basis of anisotropic photoelectron angular distributions. The neutral and anionic forms of Be4 are predicted to be tetrahedral. Franck–Condon diagonal photodetachment was observed with a photoelectron angular distribution consistent with the expected Be4–X2A1 → Be4X1A1 transition. The electron affinities of Be3 and Be4 were determined to be 11363 ± 60 and 13052 ± 50 cm–1, respectively.