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

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We report successful implementation of the time-dependent second-order many-body perturbation theory using optimized orthonormal orbital functions called time-dependent optimized second-order many-body perturbation theory [TD-OMP2] to reach…

Chemical Physics · Physics 2020-08-26 Himadri Pathak , Takeshi Sato , Kenichi L. Ishikawa

Complete active space self-consistent field (CASSCF) computations can be realized at polynomial cost via the variational optimization of the active-space two-electron reduced-density matrix (2-RDM). Like conventional approaches to CASSCF,…

Chemical Physics · Physics 2018-12-10 Mohammad Mostafanejad , A. Eugene DePrince

High-harmonic generation by a laser-driven solid slab is simulated using time-dependent density functional theory. Multiple harmonic plateaus up to very high harmonic orders are observed already at surprisingly low field strengths. The full…

Atomic Physics · Physics 2017-11-29 Kenneth K. Hansen , Tobias Deffge , Dieter Bauer

We study high order harmonics generation (HHG) in crystalline silicon and diamond subjected to near and mid-infrared laser pulses. We employ time-dependent density functional theory and solve the time-dependent Kohn-Sham equation in the…

Materials Science · Physics 2022-08-31 David Freeman , Shunsuke Yamada , Atsushi Yamada , Kazuhiro Yabana , Anatoli Kheifets

The selection rules of high harmonic generation (HHG) are investigated using three-dimensional time-dependent density functional theory (TDDFT). From the harmonic spectra obtained with various real molecules and different forms of laser…

Atomic Physics · Physics 2016-09-28 Xi Liu , Xiaosong Zhu , Liang Li , Yang Li , Qingbin Zhang , Pengfei Lan , Peixiang Lu

Ultrashort laser pulses on the attosecond timescale are typically achieved via high-order harmonic generation (HHG), a nonlinear process in which atoms interact with intense light fields to emit a broad spectrum of harmonics. HHG is…

Quantum Physics · Physics 2026-05-06 Anne Weber

We explore the roles of electronic band structure and Coulomb interactions in solid-state HHG by studying the optical response of linear atomic chains and carbon nanotubes to intense ultrashort pulses. Specifically, we simulate electron…

Mesoscale and Nanoscale Physics · Physics 2020-03-18 Sandra de Vega , Joel D. Cox , Fernando Sols , F. Javier García de Abajo

High harmonic generation (HHG) is an established means of producing coherent, short wavelength, ultrafast pulses from a compact set-up. Table-top high-harmonic sources are increasingly being used to image physical and biological systems…

We present theoretical investigations of high-order harmonic generation (HHG) resulting from the interaction of noble gases with localized surface plasmons. These plasmonic fields are produced when a metal nanoparticle is subject to a…

We investigate the feasibility of using high-harmonic generation (HHG) as a complementary probe of tunneling delay in strong-field ionization. By combining time--frequency analysis of HHG spectra obtained from full time-dependent…

Atomic Physics · Physics 2026-01-15 Amol R. Holkundkar

A mixed quantum-classical approach is introduced which allows the dynamical response of molecules driven far from equilibrium to be modeled. This method is applied to the interaction of molecules with intense, short-duration laser pulses.…

Atomic Physics · Physics 2012-05-21 Daniel Dundas

The generation of harmonics by atoms interacting with two circularly polarized and frequency related laser fields is addressed through ab initio numerical simulations. A detailed charaterization of a few specific harmonics is given. In…

Atomic Physics · Physics 2009-11-10 F. Ceccherini , N. Davini , D. Bauer , F. Cornolti

In a recent work, we introduced the foundations of an orthogonally constrained complete active space self-consistent field (OC-CASSCF) framework that produces state-specific molecular orbitals for mutually orthogonal multiconfigurational…

Chemical Physics · Physics 2026-01-28 Loris Delafosse , Vincent Robert , Saad Yalouz

The localized active space self consistent field (LASSCF) method factorizes a complete active space (CAS) wave function into an antisymmetrized product of localized active space wave function fragments. Correlation between fragments is then…

Chemical Physics · Physics 2024-03-26 Valay Agarawal , Daniel King , Matthew R. Hermes , Laura Gagliardi

We present a variational augmentation procedure to optimize the exponents of Gaussian continuum basis sets for simulating strong-field laser ionization phenomena such as higher harmonic generation (HHG) in atoms and ions using the…

Chemical Physics · Physics 2023-07-04 Sai Vijay Bhaskar Mocherla , Raghunathan Ramakrishnan

We present an implementation of coupled-perturbed complete active space self-consistent field (CP-CASSCF) theory for the computation of nuclear magnetic resonance chemical shifts using gauge-including atomic orbitals and Cholesky decomposed…

Chemical Physics · Physics 2022-09-14 Tommaso Nottoli , Sophia Burger , Stella Stopkowicz , Jürgen Gauss , Filippo Lipparini

We introduce a new computational approach for femtosecond pulse propagation in the transparency region of gases that permits full resolution in three space dimensions plus time while fully incorporating quantum coherent effects such as…

Optics · Physics 2012-07-02 M. Kolesik , E. M. Wright , J. Andreasen , J. M. Brown , D. R. Carlson , R. J. Jones

We present a numerical implementation of the gauge-invariant time-dependent configuration interaction singles (TDCIS) method [Appl. Sci. 8, 433 (2018)] for three-dimensional atoms. In our implementation, orbital-like quantity called channel…

Atomic Physics · Physics 2019-10-09 Takuma Teramura , Takeshi Sato , Kenichi L. Ishikawa

We develop a stochastic approach to time-dependent DFT with optimally-tuned range-separated hybrids containing non-local exchange, for calculating optical spectra. The attractive electron-hole interaction, which leads to the formation of…

Computational Physics · Physics 2019-06-05 Vojtech Vlcek , Roi Baer , Daniel Neuhauser

The below-threshold harmonic generation in the multiphoton ionization regime for a helium atom driven by the elliptically polarized laser field is studied numerically within the framework of two-dimensional (2D) and three-dimensional (3D)…

Optics · Physics 2024-12-11 Mikhail Yu. Emelin , Mikhail Yu. Ryabikin