A relativistic third-order algebraic diagrammatic construction theory for electron detachment, attachment and excitation problems

TL;DR

This paper introduces a highly efficient relativistic third-order algebraic diagrammatic construction (ADC(3)) method based on the Dirac-Coulomb Hamiltonian, enabling accurate calculations of ionization potentials, electron affinities, and excitation energies for heavy elements.

Contribution

The paper develops and implements a four-component relativistic ADC(3) method that improves computational efficiency and accuracy for electron detachment, attachment, and excitation problems involving heavy elements.

Findings

Good agreement with experimental data for IP, EA, and EE.

Significant computational advantages over coupled-cluster methods.

Effective for calculating properties like oscillator strengths and dipole moments.

Abstract

We present the theory and implementation of a highly efficient relativistic third-order algebraic diagrammatic construction [ADC(3)] method based on a four-component (4c) Dirac-Coulomb (DC) Hamiltonian for the calculation of ionization potentials (IP), electron affinities (EA), and excitation energies (EE). Benchmarking calculations for IP, EA, and EE were performed on both atomic and molecular systems to assess the accuracy of the newly developed four-component relativistic ADC(3) method. The results show good agreement with the available experimental data. The Hermitian nature of the 4c-ADC(3) Hamiltonian, combined with the perturbative truncation of the wave function, offers significant computational advantages over the standard equation-of-motion coupled-cluster approach, particularly for property calculations. The method's suitability for property calculations is further demonstrated by computing oscillator strengths and excited-state dipole moments for heavy elements.