Finite-nuclear-mass calculations of the leading relativistic corrections for atomic 
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 states with all-electron explicitly correlated Gaussian functions

Stanke, Monika; Adamowicz, Ludwik

doi:10.1103/physreva.100.042503

Cited by 10 publications

(2 citation statements)

References 26 publications

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“…The non-BO ECG calculations for S , P , D , and F states of atomic systems with 2–5 electrons − are among the most accurate in the literature. As the ECGs explicitly depend on the distances between the particles (electrons and nuclei), they very efficiently represent the coupled nucleus-electron motions and allow very accurate accounting of the interparticle correlation effects.…”

Section: Ecgs Used In Very Accurate Non-bo Calculations Of Stationary...mentioning

confidence: 99%

Gaussians for Electronic and Rovibrational Quantum Dynamics

Woźniak,

Adamowicz,

Pedersen

et al. 2024

J. Phys. Chem. A

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The assumptions underpinning the adiabatic Born−Oppenheimer (BO) approximation are broken for molecules interacting with attosecond laser pulses, which generate complicated coupled electronic-nuclear wave packets that generally will have components of electronic and dissociation continua as well as bound-state contributions. The conceptually most straightforward way to overcome this challenge is to treat the electronic and nuclear degrees of freedom on equal quantum-mechanical footing by not invoking the BO approximation at all. Explicitly correlated Gaussian (ECG) basis functions have proved successful for non-BO calculations of stationary molecular states and energies, reproducing rovibrational absorption spectra with very high accuracy. In this Article, we present a proof-of-principle study of the ability of fully flexible ECGs (FFECGs) to capture the intricate electronic and rovibrational dynamics generated by short, high-intensity laser pulses. By fitting linear combinations of FFECGs to accurate wave function histories obtained on a large real-space grid for a regularized 2D model of the hydrogen atom and for the 2D Morse potential, we demonstrate that FFECGs provide a very compact description of laser-driven electronic and rovibrational dynamics.

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Section: Ecgs Used In Very Accurate Non-bo Calculations Of Stationary...mentioning

confidence: 99%

Gaussians for Electronic and Rovibrational Quantum Dynamics

Woźniak,

Adamowicz,

Pedersen

et al. 2024

J. Phys. Chem. A

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“…≈ 2 cm −1 above our energy obtained with 4096-term wave function. Significantly longer ECG expansions have been employed for the 2s2p 1 P , 2s2p 3 P , and 2p 2 1 D states by Adamowicz et al [42,43,61]. In these cases, their variational energy is by 10 −8 − 10 −9 a.u.…”

Section: Variational Optimization Of the Nonrelativistic Energymentioning

confidence: 99%

Fine and hyperfine splitting of the low-lying states of $^9$Be

Puchalski,

Komasa,

Pachucki

2021

Preprint

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We perform accurate calculations of energy levels as well as fine and hyperfine splittings of the lowest 1,3 P J , 3 S1, 3 P e J , and 1,3 D J excited states of the 9 Be atom using explicitly correlated Gaussian functions and report on the breakdown of the standard hyperfine structure theory. Because of the strong hyperfine mixing, which prevents the use of common hyperfine constants, we formulate a description of the fine and hyperfine structure that is valid for an arbitrary coupling strength and may have wide applications in many other atomic systems.

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