Multiscale modeling of materials under extreme irradiation

Theory & Simulation (Theory & Simulation )

Simulation tools are offered to: 

(i) account for the thermal response in terms of high-carrier density excitation

(ii) predict the induced structural modifications. 

One of the important issues that rises when materials are exposed to extreme irradiation conditions generated by various types of electromagnetic sources, including synchrotron sources, pulsed and free-electron lasers is the estimation of the material structural and phase changes. Such changes are inadvertently dependent on material absorption properties, and the irradiation parameters and conditions. In this context, in order to link the anticipated material structural and phase changes with the irradiating source parameters and experimental measurements, a multiscale theoretical modelling toolbox is offered to describe the physical fundamentals and mechanisms that account for the associated experimental observations after single and multiple pulse irradiation at high-carrier density excitation conditions.

The multi-scale simulation code comprises the following modules that are material and source parameters dependent:

  • Energy absorption (based on results from first principles used to compute the optical properties of the material): spatio-temporal distribution of absorbed energy (Fig.a)/ Finite Difference Finite Domain Schemes, 
  • Surface plasmon excitations: computation of conditions for excitation, length and lifetime,
  • Electron excitation and relaxation processes: computation of electron temperature and equilibration through electron-phonon scattering processes, application of Two Temperature Model (Fig.b),
  • Thermal response of the lattice and phase transitions: spatio-temporal lattice temperature distribution and investigation of associated phases transitions (i.e. hydrodynamical effects and solidification)
  • Elastic and plastic effects: application of dynamic elasticity equations and coupling with above modules
  • Estimation of phase transition, modification thresholds and morphological changes.
          provided by:
Yambo is a general purpose tool for theoretical spectroscopy. The code can perform several kind of calculations ( Among these there is the simulation of materials out-of-equilibrium. Yambo can describe the effect of an external laser pulse and the following electronic and phononic dynamics.