Implementation of infinite-range exterior complex scaling to the time-dependent complete-active-space self-consistent-field method

• Published in: arXiv.org
• Main Authors: Orimo, Yuki, Sato, Takeshi, Scrinzi, Armin, Ishikawa, Kenichi L
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 23.12.2017
• Subjects: Absorption; Basis functions; Computer simulation; Field ionization; Finite element method; Harmonic generations; Mathematical analysis; Photoelectrons; Physics - Atomic Physics; Physics - Computational Physics; Scaling; Self consistent fields; Time dependence; Wave packets; Wave reflection
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1712.08779

We present a numerical implementation of the infinite-range exterior complex scaling (irECS) [Phys. Rev. A 81, 053845 (2010)] as an efficient absorbing boundary to the time-dependent complete-active-space self-consistent field (TD-CASSCF) method [Phys. Rev. A 94, 023405 (2016)] for multielectron atoms subject to an intense laser pulse. We introduce Gauss-Laguerre-Radau quadrature points to construct discrete variable representation basis functions in the last radial finite element extending to infinity. This implementation is applied to strong-field ionization and high-harmonic generation in He, Be, and Ne atoms. It efficiently prevents unphysical reflection of photoelectron wave packets at the simulation boundary, enabling accurate simulations with substantially reduced computational cost, even under significant (~ 50%) double ionization. For the case of a simulation of high-harmonic generation from Ne, for example, 80% cost reduction is achieved, compared to a mask-function absorption boundary.