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A Fast Algorithm for Real-Time Time Dependent Density Functional Theory Simulations

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Model of Cl collision with atomically thin semiconductor (MoSe2). Collision region shown in blue; red points show Cl initial positions. Simulation calculates ion energy loss based on incident and emergent velocities

Scientific Achievement
Developed new algorithm for simulating excited-state systems. Method uses bigger timestep and operates ~100x faster than conventional computations.

Significance and Impact
New method reduces computational cost and makes possible real-time simulations of ultrafast phenomena on femtosecond timescales, for systems of ~100 atoms.

Research Details

  • Conventional computational methods cannot be used to study excited systems
  • Real-time simulations model excited systems using time-dependent wave equations
  • New algorithm eliminates higher-order terms and allows bigger timestep
  • This reduces computational cost and increases speed of simulations
  • New method can simulate processes such as excitation in photovoltaic materials and demagnetization following optical excitation

Z. Wang, S. Li, L.W. Wang, Phys. Rev. Lett. Feb 2015