Linear Augmented Slater-Type Orbital Method for Free Standing Clusters

TL;DR

This paper introduces a scalable linear augmented Slater-type orbital (LASTO) method for electronic-structure calculations on free-standing atomic clusters, combining numerical and Slater-type tail functions with multigrid techniques and ScaLAPACK for eigenproblem solutions.

Contribution

The paper presents a novel scalable LASTO method that efficiently combines basis functions and numerical techniques for electronic structure calculations of atomic clusters.

Findings

Successfully tested on palladium clusters

Efficient solution of Poisson and eigenvalue problems

Scalable approach suitable for large clusters

Abstract

We have developed a Scalable Linear Augmented Slater-Type Orbital (LASTO) method for electronic-structure calculations on free-standing atomic clusters. As with other linear methods we solve the Schr\"odinger equation using a mixed basis set consisting of numerical functions inside atom-centered spheres and matched onto tail functions outside. The tail functions are Slater-type orbitals, which are localized, exponentially decaying functions. To solve the Poisson equation between spheres, we use a finite difference method replacing the rapidly varying charge density inside the spheres with a smoothed density with the same multipole moments. We use multigrid techniques on the mesh, which yield the Coulomb potential on the spheres and in turn defines the potential inside via a Dirichlet problem. To solve the linear eigen-problem, we use ScaLAPACK, a well-developed package to solve large eigensystems with dense matrices. We have tested the method on small clusters of palladium.