English
norskBlar i forfatter "Konecny, Lukas"
Viser treff 1-10 av 10
-
Accurate Relativistic Real-Time Time-Dependent Density Functional Theory for Valence and Core Attosecond Transient Absorption Spectroscopy
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-09)First principles theoretical modeling of out-of-equilibrium processes observed in attosecond pump–probe transient absorption spectroscopy (TAS) triggering pure electron dynamics remains a challenging task, especially for heavy elements and/or core excitations containing fingerprints of scalar and spin–orbit relativistic effects. To address this, we formulate a methodology for simulating TAS within ... -
Accurate X-ray Absorption Spectra near L- and M-Edges from Relativistic Four-Component Damped Response Time-Dependent Density Functional Theory
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-27)The simulation of X-ray absorption spectra requires both scalar and spin–orbit (SO) relativistic effects to be taken into account, particularly near L- and M-edges where the SO splitting of core p and d orbitals dominates. Four-component Dirac–Coulomb Hamiltonian-based linear damped response time-dependent density functional theory (4c-DR-TDDFT) calculates spectra directly for a selected frequency ... -
Cost-Efficient High-Resolution Linear Absorption Spectra Through Extrapolating the Dipole Moment from Real-Time Time-Dependent Electronic-Structure Theory
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023)We present a novel function fitting method for approximating the propagation of the time-dependent electric dipole moment from real-time electronic structure calculations. Real-time calculations of the electronic absorption spectrum require discrete Fourier transforms of the electric dipole moment. The spectral resolution is determined by the total propagation time, i.e. the trajectory length of the ... -
Exact Two-Component TDDFT with Simple Two-Electron Picture-Change Corrections: X-ray Absorption Spectra Near L- and M-Edges of Four-Component Quality at Two-Component Cost
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-02-01)X-ray absorption spectroscopy (XAS) has gained popularity in recent years as it probes matter with high spatial and elemental sensitivities. However, the theoretical modeling of XAS is a challenging task since XAS spectra feature a fine structure due to scalar (SC) and spin–orbit (SO) relativistic effects, in particular near L and M absorption edges. While full four-component (4c) calculations of ... -
Excitation Energies from Real-Time Propagation of the Four-Component Dirac–Kohn–Sham Equation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-01-21)We report the first implementation of real-time time-dependent density functional theory (RT-TDDFT) at the relativistic four-component level of theory. In contrast to the perturbative linear-response TDDFT approach (LR-TDDFT), the RT-TDDFT approach performs an explicit time propagation of the Dirac–Kohn–Sham density matrix, offering the possibility to simulate molecular spectroscopies involving ... -
Relativistic four-component linear damped response TDDFT for electronic absorption and circular dichroism calculations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-11-21)We present a detailed theory, implementation, and a benchmark study of a linear damped response time-dependent density functional theory (TDDFT) based on the relativistic four-component (4c) Dirac–Kohn–Sham formalism using the restricted kinetic balance condition for the small-component basis and a noncollinear exchange–correlation kernel. The damped response equations are solved by means of a ... -
Relativistic Real-Time Methods
(Chapter; Bokkapittel, 2023-10-25)Recent advances in laser technology enable to follow electronic motion at its natural time-scale with ultrafast pulses, leading the way towards atto- and femtosecond spectroscopic experiments of unprecedented resolution. Understanding of these laser-driven processes, which almost inevitably involve non-linear light-matter interactions and non-equilibrium electron dynamics, is challenging and requires ... -
Resolution-of-identity accelerated relativistic two- and four-component electron dynamics approach to chiroptical spectroscopies
(Journal article; Tidsskriftartikkel; Peer reviewed, 2018-11-27)We present an implementation and application of electron dynamics based on real-time time-dependent density functional theory (RT-TDDFT) and relativistic 2-component X2C and 4-component Dirac–Coulomb (4c) Hamiltonians to the calculation of electron circular dichroism and optical rotatory dispersion spectra. In addition, the resolution-of-identity approximation for the Coulomb term (RI-J) is introduced ... -
ReSpect: Relativistic spectroscopy DFT program package
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-11)With the increasing interest in compounds containing heavier elements, the experimental and theoretical community requires computationally efficient approaches capable of simultaneous non-perturbative treatment of relativistic, spin-polarization, and electron correlation effects. The ReSpect program has been designed with this goal in mind and developed to perform relativistic density functional ... -
X-ray absorption resonances near L2,3-edges from real-time propagation of the Dirac–Kohn–Sham density matrix
(Journal article; Tidsskriftartikkel; Peer reviewed, 2015-08-07)The solution of the Liouville–von Neumann equation in the relativistic Dirac–Kohn–Sham density matrix formalism is presented and used to calculate X-ray absorption cross sections. Both dynamical relaxation effects and spin–orbit corrections are included, as demonstrated by calculations of the X-ray absorption of SF6 near the sulfur L2,3-edges. We also propose an analysis facilitating the interpretation ...
