2022/11/28 by Jerryman A. Gyamfi, Gyamfi, Jerryman A., Thomas‐C. Jagau +1
Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic and Molecular Clusters (physics.atm-clus) #Atomic and Molecular Physics #Biological Physics (physics.bio-ph) #Chemical Physics (physics.chem-ph) #Computational Physics (physics.comp-ph) #FOS: Physical sciences #Spectroscopy and Quantum Chemical Studies
paper · doi:10.48550/arxiv.2211.15629
openalex publication_date 2022/11/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Complex absorbing potentials (CAPs) are artificial potentials added to electronic Hamiltonians to make the wavefunction of metastable electronic states square-integrable. This makes the electronic structure problem of electronic resonances comparable to that of electronic bound states, thus reducing the complexity of the problem. CAPs depend on two types of parameters: the coupling parameter η and a set of spatial parameters which define the onset of the CAP. It has been a common practice over the years to minimize the CAP perturbation on the physical electronic Hamiltonian by running an η-trajectory, whereby one fixes the spatial parameters and varies η. The optimal η is chosen according to the minimum log-velocity criterion. But the effectiveness of an η-trajectory strongly depends on the values of the fixed spatial parameters. In this work, we propose a more general criterion, called the ξ-criterion, which allows one to minimize any CAP parameter, including the CAP spatial parameters. Indeed, we show that fixing η and varying the spatial parameters according to a scheme (i.e., running a spatial trajectory) is a more efficient and reliable way of minimizing the CAP perturbations (which is assessed using the ξ-criterion). We illustrate the method by determining the resonance energy and width of the temporary anion of dinitrogen, at the Hartree-Fock and EOM-EA-CCSD levels, using two different types of CAPs: the box- and the smooth Voronoi-CAPs.