Electron dynamics in complex environments with real-time time dependent density functional theory in a QM-MM framework

URIEL N MORZAN; FRANCISCO F. RAMÍREZ; MARÍA BELÉN OVIEDO; CRISTIÁN G. SÁNCHEZ; DAMIÁN A. SCHERLIS; MARIANO C. GONZÁLEZ LEBRERO

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2014 vol. 140 p. 164105 - 164105

0021-9606

his article presents a time dependent density functional theory (TDDFT) implementation to propagate the Kohn-Sham equations in real time, including the effects of a molecular environment through a Quantum-Mechanics Molecular-Mechanics (QM-MM) hamiltonian. The code delivers an all-electron description employing Gaussian basis functions, and incorporates the Amber force-field in the QM-MM treatment. The most expensive parts of the computation, comprising the commutators between the hamiltonian and the density matrix?required to propagate the electron dynamics?, and the evaluation of the exchange-correlation energy, were migrated to the CUDA platform to run on graphics processing units, which remarkably accelerates the performance of the code. The method was validated by reproducing linear-response TDDFT results for the absorption spectra of several molecular species. Two different schemes were tested to propagate the quantum dynamics: (i) a leap-frog Verlet algorithm, and (ii) the Magnu