The Quest for Highly Accurate Excitation Energies: A Computational Perspective

• DOI: 10.1021/acs.jpclett.0c00014
• Publication Date: 2020-03-03T19:29:26Z
• Authors: Pierre-François Loos; Anthony Scemama; Denis Jacquemin
• Keywords: Benchmark (surveying); Basis (linear algebra)

We provide an overview of the successive steps that made possible to obtain increasingly accurate excitation energies with computational chemistry tools, eventually leading chemically vertical transition for small- and medium-size molecules. First, we describe evolution \textit{ab initio} methods employed define benchmark values, originally Roos' CASPT2 method, then CC3 method as in renowned Thiel set, more recently resurgence selected configuration interaction methods. The latter has been able deliver consistently, both single double excitations, highly small molecules, well molecules compact basis sets. Second, how these high-level creation representative sets have allowed assess fairly accurately performance computationally lighter conclude by discussing future theoretical technological developments field.