Eur. Phys. J. D 51, 225-231 (2009)
https://doi.org/10.1140/epjd/e2009-00017-9

Competition between Jahn-Teller effect and spin-orbit coupling in T_d Au₂₀^±γ, γ=1,2,3

Facultad de Ciencias, Universidad Nacional Autónoma de México, Apdo. Post. 70-646, 04510 México D.F., Mexico

Corresponding author: ^a jrsoto@correo.unam.mx

Received: 6 August 2008
Revised: 27 November 2008
Published online: 29 January 2009

Abstract

In this work we explored the competition between spin-orbit and Jahn-Teller effects as decisive influences in the ground states of the T_d Au₂₀^±γ (γ=1,2,3). All our electronic calculations were based in the relativistic density functional theory in the zeroth-order regular approximation (ZORA) to the Dirac equation. Calculations were done in both versions of ZORA: scalar relativistic and full-relativistic including the spin-orbit interaction. We concluded that for the Au₂₀^-3 ion is necessary to use a full-relativistic theory in order to predict a symmetry-lowering from tetrahedral. We predict a trigonal C_3v isomeric form for this trianion due to a Jahn-Teller distortion of its parent T_d. For the rest of ions we found a tendency to conserve their pristine tetrahedral configurations. In these cases we found one of both possibilities: a quenching of the vibronic interaction by spin-orbit coupling or simply a weak Jahn-Teller effect which is not enough to distort appreciably the cluster.