Excited-state properties

Theory & Simulation (Theory & Simulation )

The simulation of the excited state properties of complex and realistic systems represents a wide field at the forefront of research. Such systems include, e.g., surfaces, biomolecules, nanostructured materials, and potentially any combination of them. In this realm the present NFFA installation provides access to the most up-to-date and efficient ab-initio codes that, in a fully parameter-free way, make possible to describe a wealth of equilibrium and out-of- equilibrium properties. 

Excited state properties in static conditions:

Excited state properties in metastable equilibrium conditions are crucial for the understanding of the quantum-mechanical properties of the materials. The related observables can give access to the single-particle energy levels, optical excitations and much more:

  • Neutral excitations: optical absorption, energy-loss spectra;
  • Charged excitations: photoemission spectra;
  • Static magnetic susceptibilities;

 Out-of-Equilibrium / Dynamical excited state properties: 

The out-of-equilibrium dynamics describes how the system responds to external stimuli and evolves from one configuration to the other. Several dynamical processes are possible, ranging from those involving the motion of atoms and molecules (occurring on the time-scale of the picosecond) to those involving the motion of electrons, occurring on very short time- scales, ranging from femto to even atto-seconds. Both timescales can be addressed by the codes developed by, and available to, the NFFA theory installation. The offer presently includes calculation of a wealth of dynamical excited state properties such as:

  • Neutral excitations: time-resolved transient absorption, reflectivity and photoluminescence;
  • Charged excitations: time-resolved two-photon-photon photoemission, structural deformations, atomic motion and lattice deformation;
  • Piezoelectric constants;

New features will be continuously provided by the ongoing research activities carried out within NFFA.

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          provided by:
CNR-IOM (TS)
Italy
ICN2
Spain
UMIL
Italy
EPFL
Switzerland
JÜLICH
Germany
CNR-ISM
Italy
CNR-IOM (TS)
Italy
Quantum ESPRESSO
Time dependent density functional theory calculations, GW many perturbation theory calculations
ICN2
Spain
SIESTA
Time Dependent Density Functional Theory Real time dynamics of excited states Coupled electron-nuclear dynamics in excited states
CNR-ISM
Italy
Yambo
Yambo is a general purpose tool for theoretical spectroscopy. The code can perform several kind of calculations (https://www.yambo-code.eu/about/). Most of these methods fall in the realm of excited state calculations: quasi-particle properties, optical absorption, electron energy loss. Yambo can include the effect of the electron-hole attraction (excitons) as well as electron-phonon interaction (finite temperature effects) and more.
JÜLICH
Germany
FLEUR
UMIL
Italy
YAMBO
Excited state properties of bulk systems, surfaces, molecules, using many-body methods (https://www.yambo-code.eu/about/). <https://www.yambo-code.eu/about/). Optical absorption spectra, electron energy loss, Kerr effect, circular dichroism, excitonic effects, electron-phonon interaction.
UMIL
Italy
OCTOPUS
Linear and non linear optical response; pump and probe simulations on nanoalloys (Au and Ag based). Up to hundreds of atoms.
EPFL
Switzerland
Quantum ESPRESSO