We are working on the combination of first principles electronic structure theories with QOCT. In the past, we have successfully combined QOCT with time-dependent density-functional theory (TDDFT) [Castro et al., Phys. Rev. Lett. 109, 153603 (2012)]. We intend to extend this idea to other models, such as time-dependent Hartree-Fock, etc. Likewise, we have further combined the QOCT+TDDFT scheme with some form of Molecular Dynamics, in order to study the optimization of combined classical nuclei + quantum electron systems. We chose the simplest non-adiabatic MD possible, i.e. Eherenfest dynamics [Castro et al., J. Phys. A 47, 025204 (2014)]. We are extending this idea to other molecular dynamics schemes.

I am one of the founding authors of the octopus project. This code is a scientific program aimed at the ab initio virtual experimentation on a hopefully ever-increasing range of system types. Electrons are described quantum-mechanically within density-functional theory (DFT), in its time-dependent form (TDDFT) when doing simulations in time. Nuclei are described classically as point particles. Electron-nucleus interaction is described within the pseudopotential approximation. For optimal execution perfomance Octopus is parallelized using MPI and OpenMP and can scale to tens of thousands of processors. It also has support for graphical processing units (GPUs) through OpenCL.Octopus is free software, released under the GPL license, so you are free to download it, use it and modify it.

We are interested in the theoretical foundations of Molecular Dynamics, i.e. the foundations of quantum/classical models. In particular, our future goal is understanding the statistical mechanics of this type of hybrid systems, which surprisingly is not fully understood. One example of this kind or research is [Alonso et al., J. Chem. Phys. 137, 22A533 (2012)].

We are exploring a potential new route to the improvement of the exchange-and-correlation functional (XCF) approximations in density-functional theory (DFT). We propose to depart acknowledging that DFT can be formulated for fictitious electron-electron interactions – not only for the Coulomb interaction of real electrons. To each interaction corresponds a different XCF. Conversely, a given functional may correspond to an interaction potential, exactly or approximately. Therefore, our purpose is to explore manifolds of XCFs seeking for the one whose corresponding electron-electron interaction most closely resembles the real Coulomb one.