Publications by authors named "A Tkatchenko"
Complex signal vectors, particularly spectra, are integral to many scientific domains. Interpreting these signals often involves decomposing them into contributions from independent components and subtraction or deconvolution of the channel and instrument noise. Despite the fundamental nature of this task, researchers frequently rely on costly commercial tools.
View Article and Find Full Text PDFWe present computational results of many-body dispersion (MBD) interactions for 40 pairs of molecular and atomic species: hydrocarbons, silanes, corresponding fluorinated derivatives, pairs which have multiple H---H contacts between the molecules, as well as pairs having π-π interactions, and pairs of noble gases. The calculations reveal that the MBD stabilization energy () obeys a global relationship, which is . It is proportional to the product of the masses of the two molecules () and inversely proportional to the corresponding distances between the molecular centers-of-mass () or the H---H distances of the atoms mediating the interactions of the two molecules ().
View Article and Find Full Text PDFThe seventh blind test of crystal structure prediction: structure ranking methods.
Acta Crystallogr B Struct Sci Cryst Eng Mater
December 2024
Article Synopsis
- Participants from 22 research groups utilized various methods, including periodic DFT-D methods, machine learning models, and empirical force fields to assess crystal structures generated from standardized sets.
- The findings indicate that DFT-D methods generally aligned well with experimental results, while one machine learning approach showed significant promise; however, the need for more efficient research methods was emphasized due to resource consumption.
The seventh blind test of crystal structure prediction: structure generation methods.
Acta Crystallogr B Struct Sci Cryst Eng Mater
December 2024
A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern.
View Article and Find Full Text PDFArticle Synopsis
- Van der Waals (vdW) interactions, although weaker than ionic and covalent bonds, play a crucial role in determining the structure, function, and stability of various materials, including metal halide perovskites (MHPs).
- MHPs, known for their impressive optoelectronic properties due to high defect tolerance, show that vdW interactions account for about 5% of the total energy and significantly influence the properties related to defects.
- The study focuses on defects in CsPbBr, illustrating that different vdW interaction models can dramatically affect geometric structures and electronic properties, such as the fundamental bandgap and electron-vibrational dynamics, highlighting the importance of considering these interactions in material research.