A benchmark photoelectron spectroscopic and theoretical study of the electronic stability of [B12H12]2

Edoardo Aprà; Jonas Warneke; Sotiris S Xantheas; Xue-Bin Wang

doi:10.1063/1.5089510

A benchmark photoelectron spectroscopic and theoretical study of the electronic stability of [B₁₂H₁₂]²

J Chem Phys. 2019 Apr 28;150(16):164306. doi: 10.1063/1.5089510.

Authors

Edoardo Aprà¹, Jonas Warneke², Sotiris S Xantheas³, Xue-Bin Wang²

Affiliations

¹ Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P. O. Box 999, Richland, Washington 99352, USA.
² Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, Washington 99352, USA.
³ Advanced Computing, Mathematics and Data Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MS K1-83, Richland, Washington 99352, USA.

PMID: 31042907
DOI: 10.1063/1.5089510

Abstract

We report a joint benchmark study on the electronic stability of closo-dodecaborate [B₁₂H₁₂]^2- employing negative ion photoelectron spectroscopy and high level electronic structure methods. The photoelectron spectra of [B₁₂H₁₂]^2-, measured at 266, 193, and 157 nm, yield the Adiabatic and Vertical Detachment Energies (ADE and VDE) of this dianion at 0.93 ± 0.05 eV and 1.15 ± 0.05 eV, respectively, along with a ∼3 eV Repulsive Coulomb Barrier (RCB) against electron detachment. Theoretical calculations at various levels of electronic structure theory confirm the high stability of this dianion. The ADE and VDE values calculated at the coupled cluster with single, double and a perturbative estimate of triple excitations/aug-cc-PVQZ level are 0.92 and 1.16 eV, in excellent agreement with the experimental benchmark values. The comparison between the experimental and the theoretical values obtained at different levels of theory indicate that the PBE0 density functional represents a cost-effective method of sufficient accuracy to describe the molecular properties of this dianion and associated compounds. The theoretical RCB was modeled after the electrostatic potential (ESP) and point charge method (PCM) along three different detachment pathways, viz., along the B-H bond, perpendicular to a B-B bond, and normal to a B-B-B triangle. It was found that detachment of the electron along the B-H bond is preferred, as this pathway is associated with RCBs between 2.3 eV (PCM) and 3.3 eV (ESP), values that bracket the experimental estimate of ∼3 eV.