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Related papers: A complex Gaussian approach to molecular photoioni…

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We develop an approximate model for the process of direct (nonsequential) two-photon double ionization of atoms. Employing the model, we calculate (generalized) total cross sections as well as energy-resolved differential cross sections of…

Quantum Physics · Physics 2016-08-17 Morten Førre , Sølve Selstø , Raymond Nepstad

Photoelectron angular distributions (PADs) obtained from ionization of potassium atoms using moderately intense femtosecond IR fields ($\sim$10$^{12}$Wcm$^{-2}$) of various polarization states are shown to provide a route to "complete"…

Atomic Physics · Physics 2015-01-15 Paul Hockett , Matthias Wollenhaupt , Christian Lux , Thomas Baumert

We present a new adaptive method for electronic structure calculations based on novel fast algorithms for reduction of multivariate mixtures. In our calculations, spatial orbitals are maintained as Gaussian mixtures whose terms are selected…

Numerical Analysis · Mathematics 2019-06-19 Gregory Beylkin , Lucas Monzon , Xinshuo Yang

Many applications are in need of accurate photoionization cross-sections, especially in the case of complex atoms. Configuration-interaction relativistic many-body perturbation theory (CI-RMBPT) that has been successful in predicting atomic…

Atomic Physics · Physics 2014-10-09 I. M. Savukov , D. V. Filin

Various explicitly correlated Gaussian (ECG) basis sets are considered for the solution of the molecular Schr\"odinger equation with particular attention to the simplest polyatomic system, H$_3^+$. Shortcomings and advantages are discussed…

Chemical Physics · Physics 2019-12-03 Andrea Muolo , Edit Mátyus , Markus Reiher

Several physics methods for the simulation of the photoelectric effect are quantitatively evaluated with respect to a large collection of experimental data retrieved from the literature. They include theoretical and empirical calculations…

The Gaussian state description of continuous variables is adapted to describe the quantum interaction between macroscopic atomic samples and continuous-wave light beams. The formalism is very efficient: a non-linear differential equation…

Quantum Physics · Physics 2007-05-23 L. B. Madsen , K. Mølmer

We photoionize nitrogen molecules with a train of extreme ultraviolet attosecond pulses together with a weak infrared field. We measure the phase of the two-color two-photon ionization transition (molecular phase) for different states of…

Numerical simulation of complex optical structures enables their optimization with respect to specific objectives. Often, optimization is done by multiple successive parameter scans, which are time consuming and computationally expensive.…

Computational Physics · Physics 2017-07-27 P. -I. Schneider , X. Garcia Santiago , C. Rockstuhl , S. Burger

The proposal for quantum computing with rare-earth-ion qubits in inorganic crystals makes use of the inhomogeneous broadening of optical transitions in the ions to associate individual qubits with ions responding to radiation in selected…

Quantum Physics · Physics 2009-11-10 Ingela Roos , Klaus Molmer

When a laser-cooled atomic sample is optically excited, the envelope of coherent forward scattering can often be decomposed into a few complex Gaussian profiles. The convenience of Gaussian propagation helps addressing key challenges in…

Atomic Physics · Physics 2024-12-31 Xing Huang , Yuzhuo Wang , Jian Zhao , Saijun Wu

We present and discuss a new computationally inexpensive method to study, within the single active electron approximation, the interaction of a complex system with an intense ultrashort laser pulse. As a first application, we consider the…

In this paper, we propose a model and algorithm for sparse representing Gaussian molecular surface. The original Gaussian molecular surface is approximated by a relatively small number of radial basis functions (RBFs) with rotational…

Numerical Analysis · Mathematics 2019-09-20 Sheng Gui , Minxin Chen , Benzhuo Lu

In conditions where the interaction betweeen an atom and a short high-frequency extreme ultraviolet laser pulse is a perturbation, we show that a simple theoretical approach, based on Coulomb-Volkov-type states, can make reliable…

Atomic Physics · Physics 2009-11-07 Guillaume Duchateau , Eric Cormier , Robert Gayet

We propose efficient algorithms for classically simulating Gaussian unitaries and measurements applied to non-Gaussian initial states. The constructions are based on decomposing the non-Gaussian states into linear combinations of Gaussian…

Quantum Physics · Physics 2026-02-26 Oliver Hahn , Ryuji Takagi , Giulia Ferrini , Hayata Yamasaki

A review of some recently developed methods of calculating multiple differential cross-sections of photoionization and electron impactionization of atoms and molecules having two active electrons is presented. The methods imply original…

A Gaussian resolution method for the computation of equilibrium density matrices rho(T) for a general multidimensional quantum problem is presented. The variational principle applied to the ``imaginary time'' Schroedinger equation provides…

Quantum Physics · Physics 2009-11-10 P. Frantsuzov , A. Neumaier , V. A. Mandelshtam

We present a quantum kinetic approach for the time-resolved description of many-body effects in photoionization processes in atoms. The method is based on the non-equilibrium Green functions formalism and solves the Keldysh/Kadanoff-Baym…

Atomic Physics · Physics 2015-05-13 D. Hochstuhl , K. Balzer , S. Bauch , M. Bonitz

Realistic modeling of stellar spectra requires accurate radiative opacity coefficients. Owing to the fragmentary nature of existing data from rigorous quantum-mechanical calculations, photoionization coefficients based on the…

Solar and Stellar Astrophysics · Physics 2026-04-22 René D. Rohrmann

In this contribution we present a protocol to evaluate partial and total Auger decay rates combining the restricted active space self-consistent field electronic structure method for the bound part of the spectrum and numerically obtained…

Chemical Physics · Physics 2019-10-30 Gilbert Grell , Oliver Kühn , Sergey I. Bokarev