Massively Parallelized Real-Time Propagation via Plane-wave based Time-Dependent Density Functional Theory

The real-time time-dependent density functional theory (rt-TDDFT) is an attractive model for simulating and calculating quantum dynamics properties such as the optical absorption spectrum. Several developments and applications in this field have been achieved in recent years. However, rt-TDDFT calculations require substantial computation resources. Applying rt-TDDFT to increasingly large systems requires developing methods to overcome computational bottlenecks, one being the cost needed to form the time propagator for the RT-TDDFT equations.

To this end, we present an efficient massively parallelized rt-TDDFT implementation in the C++-based package QBOX. We validate our approach by comparing our results to the original QBOX wavefunction routine. We present current density and optical absorption calculations of hexagonal boron nitride (h-BN) and ozone molecules photodissociation as benchmark applications. Using ultrashort laser pulse and Ehrenfest dynamics calculations, we show that the results of our calculation are consistent with the previously reported results and show faster computational speed by reducing the MPI communication routine.