Benchmarking Gaussian Basis Sets in Quantum-Chemical Calculations of Photoabsorption Spectra of Light Atomic Clusters

Abstract

The choice of Gaussian basis functions for computing the ground-state properties of molecules, and clusters, employing wave-function-based electron-correlated approaches, is a well-studied subject. However, the same cannot be said when it comes to the excited-state properties of such systems, in general, and optical properties, in particular.The aim of the present study is to understand how the choice of basis functions affects the calculations of linear optical absorption in clusters, qualitatively, and quantitatively.For this purpose, we have calculated linear optical absorption spectra of several small charged and neutral clusters, namely, Li 2 , Li 3 , Li 4 , B + 2 , B + 3 , Be + 2 , and Be + 3 , using a variety of Gaussian basis sets. The calculations were performed within the frozen-core approximation, and a rigorous account of electron correlation effects in the valence 1