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DOE OSTI · 3366864

Hybrid Basis and Multi-Center Grid Method for Strong-Field Processes

Hamer, Kyle A. [Univ. of Central Florida, Orlando, FL (United States)] (ORCID:0000000319778704)·Gharibnejad, Heman [Computational Physics Inc., Springfield, VA (United States)] (ORCID:0000000182000474)·Argenti, Luca [Univ. of Central Florida, Orlando, FL (United States)]·Douguet, Nicolas [Univ. of Central Florida, Orlando, FL (United States)]
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Abstract

We present a time-dependent framework that combines a hybrid basis, consisting of Gaussian-type orbitals (GTOs) and finite-element discrete-variable representation (FEDVR) functions, with a multicenter grid to simulate strong-field and attosecond dynamics in atoms and molecules. The method incorporates the construction of the orthonormal hybrid basis, the evaluation of electronic integrals, a unitary time-propagation scheme, and the extraction of optical and photoelectron observables. Its accuracy and robustness are benchmarked on one-electron systems such as atomic hydrogen and the dihydrogen cation (H$^+_2$) through comparisons with essentially-exact reference results for bound-state energies, high-harmonic generation spectra, photoionization cross sections, and photoelectron momentum distributions. This work establishes the groundwork for its integration with quantum-chemistry methods, which is already operational but will be detailed in future work, thereby enabling ab initio simulations of correlated polyatomic systems in intense ultrafast laser fields.

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74 ATOMIC AND MOLECULAR PHYSICSatomic, molecular and optical physicsattosecond and strong-field physicstime-dependent numerical methods

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Hamer, Kyle A. [Univ. of Central Florida, Orlando, FL (United States)] (ORCID:0000000319778704), Gharibnejad, Heman [Computational Physics Inc., Springfield, VA (United States)] (ORCID:0000000182000474), Argenti, Luca [Univ. of Central Florida, Orlando, FL (United States)], Douguet, Nicolas [Univ. of Central Florida, Orlando, FL (United States)]. 2025-11-17. Hybrid Basis and Multi-Center Grid Method for Strong-Field Processes. https://doi.org/10.3390/atoms13110092

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