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The interaction of strong laser fields with matter intrinsically provides powerful tools to image transient dynamics with an extremely high spatiotemporal resolution. Here, we study strong-field ionisation of laser-aligned molecules and…

We consider a charged particle driven by a time-dependent flux threading a quantum ring. The dynamics of the charged particle is investigated using classical treatment, Fourier expansion technique, time-evolution method, and…

Mesoscale and Nanoscale Physics · Physics 2008-07-29 Pi-Gang Luan , Chi-Shung Tang

An implementation of coupled-cluster (CC) theory to treat atoms and molecules in finite magnetic fields is presented. The main challenges stem from the magnetic-field dependence in the Hamiltonian, or, more precisely, the appearance of the…

Chemical Physics · Physics 2015-09-02 Stella Stopkowicz , Jürgen Gauss , Kai K. Lange , Erik I. Tellgren , Trygve Helgaker

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

A new alternate method for evaluating linear response theory is formally developed, and results are presented. This method involves the time-evolution of the system using TDHF and is constructed directly on top of a static Hartree-Fock…

Nuclear Theory · Physics 2009-11-11 A. S. Umar , V. E. Oberacker

We examine the relation between the recently proposed time-dependent quantum Monte Carlo (TDQMC) method and the principles of stochastic quantization. In both TDQMC and stochastic quantization particle motion obeys stochastic guidance…

Atomic Physics · Physics 2009-11-13 Ivan P. Christov

In this paper, we study the nuclear gradients of heat bath configuration interaction self-consistent field (HCISCF) wave functions and use them to optimize molecular geometries for various molecules. We show that the HCISCF nuclear…

Chemical Physics · Physics 2022-09-14 James E. T. Smith , Joonho Lee , Sandeep Sharma

Microscopic methods and tools to describe nuclear dynamics have considerably been improved in the past few years. They are based on the time-dependent Hartree-Fock (TDHF) theory and its extensions to include pairing correlations and quantum…

Nuclear Theory · Physics 2018-09-13 C. Simenel , A. S. Umar

We develop a time-dependent variational Monte Carlo (t-VMC) method for quantum dynamics of strongly correlated electrons. The t-VMC method has been recently applied to bosonic systems and quantum spin systems. Here, we propose a…

Strongly Correlated Electrons · Physics 2015-12-22 Kota Ido , Takahiro Ohgoe , Masatoshi Imada

A time-dependent equation of motion coupled cluster singles and doubles (TD-EOM-CCSD) method is implemented, which uses a reduced basis calculated with the asymmetric band Lanczos algorithm. The approach is used to study weak-field…

Many-electron wavepacket dynamics based on time-dependent configuration interaction (TDCI) is a numerically rigorous approach to quantitatively model electron-transfer across molecular junctions. TDCI simulations of cyanobenzene…

Chemical Physics · Physics 2020-06-24 Raghunathan Ramakrishnan

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 nuclear time-dependent density functional theory (TDDFT) is a tool of choice for describing various dynamical phenomena in atomic nuclei. In a recent study, we reported an extension of the framework - the multiconfigurational TDDFT…

Nuclear Theory · Physics 2024-01-24 Petar Marević , David Regnier , Denis Lacroix

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 coupling of electronic and nuclear motion in polyatomic molecules is at the heart of attochemistry. The molecular properties, transient structures and reaction mechanism of these many-body quantum objects are defined on the level of…

Chemical Physics · Physics 2024-03-12 David Schwickert , Andreas Przystawik , Dian Diaman , Detlef Kip , Jon P. Marangos , Tim Laarmann

The variational multiparticle-multihole configuration mixing approach (MPMH) to nuclei has been proposed about a decade ago. While the first applications followed rapidly, the implementation of the full formalism of this method has only…

Nuclear Theory · Physics 2017-04-26 C. Robin , N. Pillet , M. Dupuis , J. Le Bloas , D. Peña Arteaga , J. -F. Berger

We consider a charged particle which is driven by a time-dependent flux threading a circular ring system. Various approaches including classical treatment, Fourier expansion method, time-evolution method, and Lewis-Riesenfeld method are…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Pi-Gang Luan , Chi-Shung Tang

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

It was recently shown [Phys. Rev. Lett. 105, 123002 (2010)] that the complete wavefunction for a system of electrons and nuclei evolving in a time-dependent external potential can be exactly factorized into an electronic wavefunction and a…

Chemical Physics · Physics 2015-06-11 Ali Abedi , Neepa T. Maitra , E. K. U. Gross

The exact factorization of the time-dependent electron-nuclear wavefunction has been employed successfully in the field of quantum molecular dynamics simulations for interpreting and simulating light-induced ultrafast processes. In this…

Chemical Physics · Physics 2021-09-29 Federica Agostini , E. K. U. Gross