Efficient implementation of the single-reference algebraic diagrammatic construction theory for charged excitations: Applications to the TEMPO radical and DNA base pairs

TL;DR

This paper introduces an efficient implementation of the EA/IP-ADC methods for charged excitations, enabling accurate calculations of spectra and electron affinities for complex molecules like TEMPO and DNA base pairs.

Contribution

The authors develop a computationally efficient, spin-adapted, and parallelized EA/IP-ADC implementation for large systems, improving accuracy and performance over previous methods.

Findings

Accurately computed photoelectron spectrum of TEMPO radical.

Determined electron affinities of TEMPO and DNA base pairs.

Achieved good agreement with experimental and theoretical data.

Abstract

We present an efficient implementation of the second- and third-order single-reference algebraic diagrammatic construction theory for electron attachment (EA) and ionization (IP) energies and spectra (EA/IP-ADC(n), n = 2, 3). Our new EA/IP-ADC program features spin adaptation for closed-shell systems, density fitting for efficient handling of the two-electron integral tensors, as well as vectorized and parallel implementation of tensor contractions. We demonstrate capabilities of our efficient implementation by applying the EA/IP-ADC(n) (n = 2, 3) methods to compute the photoelectron spectrum of the TEMPO radical, as well as the vertical and adiabatic electron affinities of TEMPO and two DNA base pairs (guanine-cytosine and adenine-thymine). The spectra and electron affinities computed using large diffuse basis sets with up to 1028 molecular orbitals are found to be in a good agreement with the best available results from the experiment and theoretical simulations.