Performance of density-functional-theory and random-phase-approximation methods on the study of transition-metal clusters: the Ta_n clusters as an example

Abstract

Recently developed density-functional-theory (DFT) and random-phase-approximation (RPA) methods are used to study competing isomers of some negatively charged Ta clusters, namely Ta₁₂^- and Ta₁₀^-, in an attempt to find a suitable strategy towards accurate studies of transition-metal clusters based on DFT. Also the neutral and cationic forms Ta₁₂^(0,+) of the twelve-atom cluster are studied. The results are compared with experimental information obtained by several methods that differ in the property under study and the total electric charge of the clusters. We find that a careful choice of the density functional, the use of relativistic two-component methods, eventually in combination with all-electron basis sets, and the application of RPA-type methods, may all be necessary steps for a good assessment. Such an assessment should be made in relation to several experimental properties as much as possible.

GRAPHICAL ABSTRACT

KEYWORDS:

• Density-functional methods
• random-phase-approximation methods
• metal clusters

Acknowledgements

We thank Laurenz Monzel (Saarland University) and Christof Holzer (Karlsruhe Institute of Technology) for help with details of the computations with Turbomole. Our research was supported by the Bundesministerium für Bildung und Forschung (BMBF) through the Helmholtz Association via the PoF IV programme ‘Materials Systems Engineering' (MSE). JRF acknowledges support from the Xunta de Galicia by the GRC programme.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Bundesministerium für Bildung und Forschung (BMBF): PoF IV program “Materials Systems Engineering”; Xunta de Galicia: Grant Number GRC Program.