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Related papers: Time-Dependent Complete-Active-Space Self-Consiste…

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Strong field photoemission and electron recollision provide a viable route to extract electronic and nuclear dynamics from molecular targets with attosecond temporal resolution. However, since an {\em ab-initio} treatment of even the…

Atomic Physics · Physics 2016-11-02 N. Suárez , A. Chacón , M. F. Ciappina , B. Wolter , J. Biegert , M. Lewenstein

This chapter provides a basic introduction to excited-state extensions of density functional theory (DFT), including time-dependent (TD-)DFT in both its linear-response and its explicitly time-dependent formulations. As applied to the…

Chemical Physics · Physics 2023-05-02 John M. Herbert

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

We present a theoretical description of femtosecond laser induced dynamics of the hydrogen molecule and of singly ionised sodium dimers, based on a real-space, real-time, implementation of time-dependent density functional theory (TDDFT).…

Condensed Matter · Physics 2007-05-23 Alberto Castro , M. A. L. Marques , Julio A. Alonso , George F. Bertsch , Angel Rubio

Time-frequency (TF) analysis is a powerful tool for exploring ultrafast dynamics in atoms and molecules. While some TF methods have demonstrated their usefulness and potential in several of quantum systems, a systematic comparison among…

Data Analysis, Statistics and Probability · Physics 2021-06-21 Yae-lin Sheu , Hau-tieng Wu , Liang-Yan Hsu

The structure of approximate two electron wavefunction is deeply investigated, both theoretically and numerically, in the strong-field driven ionization dynamics. Theoretical analyses clarify that for two electron singlet systems, the…

Atomic Physics · Physics 2014-11-13 Takeshi Sato , Kenichi L Ishikawa

We derive and implement analytic nuclear gradients and derivative couplings for a constrained Complete Active Space Self-Consistent Field with a small active space designed to model electron or hole transfer. Using a Lagrangian formalism,…

Computational Physics · Physics 2025-09-01 Tian Qiu , Joseph E. Subotnik

Accurately resolving many-body satellite features in molecular core-level spectra requires theoretical approaches that capture electron correlation both efficiently and systematically. The recently developed time-dependent double…

Quantum Physics · Physics 2026-05-12 Vibin Abraham , Priyabrata Senapati , Himadri Pathak , Bo Peng

Computation of electronic spectra is one of the most important applications of methods capturing static electron correlation, including complete-active-space self-consistent field (CASSCF) and post-CASSCF theories. Performance of these…

Chemical Physics · Physics 2025-11-19 Reza G. Shirazi , Alexander Zech , Peter Pinski , Vladimir V. Rybkin

We present a novel theoretical approach to simulate spin, time and angular-resolved photoelectron spectroscopy (ARPES) from first principles that is applicable to surfaces, thin films, few layer systems, and low-dimensional nanostructures.…

Computational Physics · Physics 2017-01-03 Umberto De Giovannini , Hannes Hübener , Angel Rubio

The computation of excited states within the Complete Active Space Self-Consistent Field (CASSCF) framework remains a significant challenge in quantum chemistry, both theoretically and algorithmically. In this work, we extend the K\"ahler…

Chemical Physics · Physics 2026-04-16 Laura Grazioli , Yukuan Hu , Tommaso Nottoli , Filippo Lipparini , Eric Cancès

In this work, two approaches for simulating X-ray absorption (XA) spectra with the complete active space self-consistent field (CASSCF) linear response (LR) method are introduced. The first approach employs the well-known core-valence…

Chemical Physics · Physics 2022-03-10 Benjamin Helmich-Paris

The first 52 fs of a time evolution of the electron density in OCS after an interaction with an intense sub 10 fs laser pulse are studied using the time-dependent density functional theory. The nuclear motion in this linear trimer is…

Materials Science · Physics 2008-08-18 G. Bilalbegovic

The time-dependent surface flux method developed for the description of electronic spectra [L. Tao and A. Scrinzi, New J. Phys. 14, 013021 (2012); A. Scrinzi, New J. Phys. 14, 085008 (2012)] is extended to treat dissociation and…

Atomic Physics · Physics 2014-10-09 Lun Yue , Lars Bojer Madsen

The increasing need to simulate the dynamics of photoexcited molecular and nanosystems in the sub-picosecond regime demands new efficient tools able to describe the quantum nature of matter at a low computational cost. By combining the…

The time-dependent Hartree-Fock (TDHF) method is an approach to simulate the mean field dynamics of electrons within the assumption that the electrons move independently in their self-consistent average field and within the space of single…

Quantum Physics · Physics 2023-09-06 Sahil Gulania , Stephen K. Gray , Yuri Alexeev , Bo Peng , Niranjan Govind

Two-color laser fields offer significantly enhanced control over electron excitation dynamics under ultrashort intense laser pulses compared to monochromatic fields. However, their strong nonlinearity necessitates computationally expensive…

Optics · Physics 2025-07-03 Mizuki Tani , Kenichi L. Ishikawa , Tomohito Otobe

Real-time time-dependent density functional theory, in conjunction with the Ehrenfest molecular dynamics scheme, is becoming a popular methodology to investigate ultrafast phenomena on the nanoscale. Thanks to recent developments, it is…

Materials Science · Physics 2020-08-18 Jannis Krumland , Ana M. Valencia , Stefano Pittalis , Carlo A. Rozzi , Caterina Cocchi

Despite the variety of available computational approaches, state-of-the-art methods for calculating excitation energies such as time-dependent density functional theory (TDDFT), are computationally demanding and thus limited to moderate…

Chemical Physics · Physics 2022-03-10 Martina Stella , Kritam Thapa , Luigi Genovese , Laura E. Ratcliff

Time-dependent density functional theory is implemented in an all electron solid-state code for the case of fully non-collinear spins. We use this to study laser induced demagnetization in Fe, Co and Ni. It is shown that this…

Materials Science · Physics 2014-06-26 K. Krieger , J. K. Dewhurst , P. Elliott , S. Sharma , E. K. U. Gross