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Related papers: Time-dependent complete-active-space self-consiste…

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The generation of harmonics by atoms or ions in a two-color, coplanar field configuration with commensurate frequencies is investigated through both, an analytical calculation based on the Lewenstein model and the numerical ab initio…

Atomic Physics · Physics 2009-11-07 F. Ceccherini , D. Bauer , F. Cornolti

We calculate the high-harmonic generation (HHG) spectra, strong-field ionization, and time-dependent dipole-moment of Ne using explicitly time-dependent optimized second-order many-body perturbation method (TD-OMP2) where both orbitals and…

Chemical Physics · Physics 2020-08-18 Himadri Pathak , Takeshi Sato , Kenichi L. Ishikawa

Analytic energy gradients are presented for a variational two-electron reduced-density-matrix-driven complete active space self-consistent field (v2RDM-CASSCF) procedure that employs the density-fitting (DF) approximation to the…

Chemical Physics · Physics 2018-11-29 J. Wayne Mullinax , Evgeny Epifanovsky , Gergely Gidofalvi , A. Eugene DePrince

In parallel with the evolution of femtosecond and attosecond laser as well as free-electron laser technology, a variety of theoretical methods have been developed to describe the behavior of atoms, molecules, clusters, and solids under the…

Atomic Physics · Physics 2015-11-12 Kenichi L. Ishikawa , Takeshi Sato

In this paper, we investigate the effects of full electronic correlation on the high harmonic generation in the helium atom subjected to laser pulses of extremely high intensity. To do this, we perform real-time propagations of the helium…

Chemical Physics · Physics 2022-05-18 Aleksander P. Woźniak , Michał Przybytek , Maciej Lewenstein , Robert Moszyński

Time-dependent coupled-cluster method with time-varying orbital functions, called time-dependent optimized coupled- cluster (TD-OCC) method, is formulated for multielectron dynamics in an intense laser field. We have successfully derived…

Chemical Physics · Physics 2018-03-14 Takeshi Sato , Himadri Pathak , Yuki Orimo , Kenichi L. Ishikawa

The generation of high harmonics in laser-irradiated light homonuclear diatomics (H2+, N2 and O2) compared to that in atomic counterparts (of nearly identical binding energy) is studied within the velocity gauge version of conventional…

Atomic Physics · Physics 2009-11-11 Vladimir I. Usachenko , Pavel E. Pyak , Shih-I Chu

The interaction of a helium atom with intense short 800 nm laser pulse is studied theoretically beyond the single-active-electron approximation. For this purpose, the time-dependent Schr\"odinger equation for the two-electron wave packet…

Atomic and Molecular Clusters · Physics 2017-03-08 Anton N. Artemyev , Lorenz S. Cederbaum , Philipp V. Demekhin

We apply a three-dimensional (3D) implementation of the time-dependent restricted-active-space self-consistent-field (TD-RASSCF) method to investigate effects of electron correlation in the ground state of Be as well as in its…

Atomic Physics · Physics 2017-06-07 Juan J. Omiste , Wenliang Li , Lars Bojer Madsen

We present a new implementation of the hybrid antisymmetrized Coupled Channels (haCC) method in the framework of the tRecX [A. Scrinzi, Comp. Phys. Comm., 270:108146, 2022.]. The method represents atomic and molecular multi-electron…

Computational Physics · Physics 2024-05-02 Hareesh Chundayil , Vinay P. Majety , Armin Scrinzi

Bichromatic extreme-ultraviolet pulses from a seeded free-electron laser enable us to measure photoelectron angular distribution (PAD) as a function of the relative phase between the different wavelength components. The time-dependent…

Atomic Physics · Physics 2021-05-26 Yuki Orimo , Oyunbileg Tugs , Takeshi Sato , Daehyun You , Kiyoshi Ueda , Kenichi L. Ishikawa

We present a wave-function based method to solve the time-dependent many-electron Schr\"odinger equation (TDSE) with special emphasis on strong-field ionization phenomena. The theory builds on the configuration-interaction (CI) approach…

Quantum Physics · Physics 2014-12-11 Sebastian Bauch , Lasse Kragh Sørensen , Lars Bojer Madsen

We present numerical simulations of high-order harmonic generation in helium using a temporally synthesised and spatially non-homogeneous strong laser field. The combination of temporal and spatial laser field synthesis results in a…

We present a novel implementation of the complete active space self-consistent field (CASSCF) method that makes use of the many-body expanded full configuration interaction (MBE-FCI) method to incrementally approximate electronic structures…

We report the implementation of a cost-effective approximation method within the framework of time-dependent optimized coupled-cluster (TD-OCC) method [J. Chem. Phys. 148, 051101 (2018)] for real-time simulations of intense laser-driven…

Chemical Physics · Physics 2020-04-22 Himadri Pathak , Takeshi Sato , Kenichi L. Ishikawa

We investigate the effect of dynamic electron correlation on high-harmonic generation in helium atoms using intense visible light (\lambda=390nm). Two complementary approaches are used which account for correlation in an approximate manner:…

Quantum Physics · Physics 2009-05-21 G. A. McKenna , R. Nepstad , J. F. McCann , D. Dundas

We extend our recently developed semiclassical strong-field Herman-Kluk propagator (SFHK) method to calculate high-order harmonic generation (HHG) for atoms in intense lasers. We show that our method, based on a combination of the…

Atomic Physics · Physics 2026-01-27 Phi-Hung Tran , Hao Quan Truong , R. Esteban Goetz , Anh-Thu Le

Precise control of the electron phase accumulated during its sub-cycle motion within intense laser fields is essential in strong-field physics, yet remains mostly indirect and complicated so far. In this Letter, we develop a novel approach…

We propose a semi-classical approach based on the Vlasov equation to describe the time-dependent electronic dynamics in a bulk simple metal under an ultrashort intense laser pulse. We include in the effective potential not only the ionic…

Plasma Physics · Physics 2021-09-08 Mizuki Tani , Tomohito Otobe , Yasushi Shinohara , Kenichi L. Ishikawa

High-harmonic generation in two-colour ($\omega-2\omega$) counter-rotating circularly polarised laser fields opens the path to generate isolated attosecond pulses and attosecond pulse trains with controlled ellipticity. The generated…