Browsing by Author "Larsen, Ask Hjorth"

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GPAW : An open Python package for electronic structure calculations
(2024-03-07) Mortensen, Jens Jørgen; Larsen, Ask Hjorth; Kuisma, Mikael; Ivanov, Aleksei V.; Taghizadeh, Alireza; Peterson, Andrew; Haldar, Anubhab; Dohn, Asmus Ougaard; Schäfer, Christian; Jónsson, Elvar Örn; Hermes, Eric D.; Nilsson, Fredrik Andreas; Kastlunger, Georg; Levi, Gianluca; Jónsson, Hannes; Häkkinen, Hannu; Fojt, Jakub; Kangsabanik, Jiban; Sødequist, Joachim; Lehtomäki, Jouko; Heske, Julian; Enkovaara, Jussi; Winther, Kirsten Trøstrup; Dulak, Marcin; Melander, Marko M.; Ovesen, Martin; Louhivuori, Martti; Walter, Michael; Gjerding, Morten; Lopez-Acevedo, Olga; Erhart, Paul; Warmbier, Robert; Würdemann, Rolf; Kaappa, Sami; Latini, Simone; Boland, Tara Maria; Bligaard, Thomas; Skovhus, Thorbjørn; Susi, Toma; Maxson, Tristan; Rossi, Tuomas; Chen, Xi; Schmerwitz, Yorick Leonard A.; Schiøtz, Jakob; Olsen, Thomas; Jacobsen, Karsten Wedel; Thygesen, Kristian Sommer
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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.
Real-time time-dependent density functional theory implementation of electronic circular dichroism applied to nanoscale metal-organic clusters
(2021-03-21) Makkonen, Esko; Rossi, Tuomas P.; Larsen, Ask Hjorth; Lopez-Acevedo, Olga; Rinke, Patrick; Kuisma, Mikael; Chen, Xi
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Electronic circular dichroism (ECD) is a powerful spectroscopy method for investigating chiral properties at the molecular level. ECD calculations with the commonly used linear-response time-dependent density functional theory (LR-TDDFT) framework can be prohibitively costly for large systems. To alleviate this problem, we present here an ECD implementation within the projector augmented-wave method in a real-time-propagation TDDFT framework in the open-source GPAW code. Our implementation supports both local atomic basis sets and real-space finite-difference representations of wave functions. We benchmark our implementation against an existing LR-TDDFT implementation in GPAW for small chiral molecules. We then demonstrate the efficiency of our local atomic basis set implementation for a large hybrid nanocluster and discuss the chiroptical properties of the cluster.