GPAW: An open Python package for electronic structure calculations

Abstract

We review the GPAW open-source Python package for electronic structure calculations. GPAW is based on the projector-augmented wave method and can solve the self-consistent density functional theory (DFT) equations using three different wave-function representations, namely real-space grids, plane waves, and numerical atomic orbitals. The three representations are complementary and mutually independent and can be connected by transformations via the real-space grid. This multi-basis feature renders GPAW highly versatile and unique among similar codes. By virtue of its modular structure, the GPAW code constitutes an ideal platform for the implementation of new features and methodologies. Moreover, it is well integrated with the Atomic Simulation Environment (ASE), providing a flexible and dynamic user interface. In addition to ground-state DFT calculations, GPAW supports many-body GW band structures, optical excitations from the Bethe–Salpeter Equation, variational calculations of excited states in molecules and solids via direct optimization, and real-time propagation of the Kohn–Sham equations within time-dependent DFT. A range of more advanced methods to describe magnetic excitations and non-collinear magnetism in solids are also now available. In addition, GPAW can calculate non-linear optical tensors of solids, charged crystal point defects, and much more. Recently, support for graphics processing unit (GPU) acceleration has been achieved with minor modifications to the GPAW code thanks to the CuPy library. We end the review with an outlook, describing some future plans for GPAW.

Orbital-Optimized Versus Time-Dependent Density Functional Calculations of Intramolecular Charge Transfer Excited States

“…All TD-DFT calculations are performed with version 5.0 of the ORCA software , and use the linear-response and adiabatic approximations, with all the electrons (core and valence) represented with the aug-cc-pVDZ basis set. The orbital-optimized calculations with the LDA and GGA functionals are performed with the grid-based projector augmented wave (GPAW) software, − making use of the frozen core approximation and the PAW formalism . For these calculations, the valence electrons are represented in an LCAO basis consisting of primitive Gaussian functions taken from the aug-cc-pVDZ set − augmented with a single set of numerical atomic orbitals (Gaussian basis set + sz). , The orbitals are represented on a uniform grid with a spacing between the points of 0.15 Å.…”

Origin of Macroscopic Observables of Strongly Coupled Metal Nanoparticle–Molecule Systems from Microscopic Electronic Properties

“…The two elements are placed in a linear manner, reminiscent of J-aggregates, with the long axis of the molecule along the applied electric field kick (see the inset in Figure a). The NP–molecule systems studied here are modeled using the RT-TDDFT method as implemented in the GPAW package − with a total simulation time of 30 fs, a time step δ t = 15 as, and the Perdew–Burke–Ernzerhof (PBE) exchange–correlation functional.…”

Dynamic stability of Pt-based alloys for fuel-cell catalysts calculated from atomistics

“…We performed ab initio electronic structure calculations using density functional theory (DFT) by employing the GPAW (grid-based projector-augmented wave) code 61–63 with a plane wave (PW) basis set. The atomic manipulations and visualizations were handled in Atomic Simulation Environment (ASE).…”

“…Atomistic manipulations were performed in the Atomic Simulation Environment (ASE), 64 which is freely available at and in repository format at . Electronic structure calculations (density functional theory) was performed in GPAW, 61 which is freely available at and in repository format at . The corresponding author and his group routinely submit code to both projects.…”