Michal Chodkiewicz

Michal Chodkiewicz
University of Warsaw | UW · Research Laboratory of Theoretical Chemistry and Crystallography

About

27
Publications
1,278
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
147
Citations

Publications

Publications (27)
Article
Full-text available
Hirshfeld atom refinement (HAR) is one of the most effective methods for obtaining accurate structural parameters for hydrogen atoms from X-ray diffraction data. Unfortunately, it is also relatively computationally expensive, especially for larger molecules due to wavefunction calculations. Here, a fragmentation approach has been tested as a remedy...
Article
The advancement in 3D electron diffraction (3D ED) techniques that lead to a revolution in molecular structure determination using nano-sized crystals is now achieving atomic resolution. The structures can be obtained from 3D ED data with tools similar to those used for X-ray structure determination. In this context, the MoPro software, originally...
Article
Full-text available
Correction for 'Towards accurate and precise positions of hydrogen atoms bonded to heavy metal atoms' by Magdalena Woińska et al., Chem. Commun., 2021, 57, 3652-3655, DOI: 10.1039/D0CC07661A.
Article
Full-text available
A comparison of five X-ray structures of transition-metal-bound hydride complexes, successfully refined using Hirshfeld Atom Refinement (HAR) against low resolution X-ray diffraction data (including the positions and ADPs of all hydrogen atoms), with neutron structures shows that using aspherical atomic scattering factors instead of spherical ones...
Article
Full-text available
Hirshfeld atom refinement is one of the most successful methods for the accurate determination of structural parameters for hydrogen atoms from X-ray diffraction data. This work introduces a generalization of the method [generalized atom refinement (GAR)], consisting of the application of various methods of partitioning electron density into atomic...
Article
Hydrogen is present in almost all of the molecules in living things. It is very reactive and forms bonds with most of the elements, terminating their valences and enhancing their chemistry. X-ray diffraction is the most common method for structure determination. It depends on scattering of X-rays from electron density, which means the single electr...
Article
Full-text available
A revolution in resolution is occurring now in electron microscopy arising from the development of methods for imaging single particles at cryogenic temperatures and obtaining electron diffraction data from nanocrystals of small organic molecules or macromolecules. Near-atomic or even atomic resolution of molecular structures can be achieved. The b...
Preprint
A revolution in resolution is occurring now in electron microscopy arising from the development of methods for imaging single particles at cryogenic temperatures and obtaining electron diffraction data from nanocrystals of small organic molecules or macromolecules. Near- atomic or even atomic resolution of molecular structures can be achieved. The...
Article
It has been recently established that the accuracy of structural parameters from X-ray refinement of crystal structures can be improved by using a bank of aspherical pseudoatoms instead of the classical spherical model of atomic form factors. This comes, however, at the cost of increased complexity of the underlying calculations. In order to facili...
Article
Full-text available
The author list of the article by Michels-Clark et al. [ J. Appl. Cryst. (2016), 49 , 497–506] is amended with the addition of Michal Chodkiewicz, Thomas Weber and Hans-Beat Bürgi. The complete list of authors is Tara Michels-Clark, Andrei Savici, Vickie Lynch, Xiaoping Wang, Michal Chodkiewicz, Thomas Weber, Hans-Beat Bürgi and Christina Hoffmann.
Article
Two-dimensional diffuse X-ray scattering from an organic salt [ N -(3-(2,6-dimethylanilino)-1-methylbut-2-enylidene)-2,6-dimethylanilinium chloride, C 21 H 27 N 2 + Cl − ] was interpreted with the help of an analytical model of diffuse scattering. An analysis of the relationship between symmetry and diffuse scattering for the studied system has bee...
Chapter
This chapter revisits critical aspects of pseudoatom interpretation of X-ray Bragg diffraction data to derive the crystalline electron density experimentally. The main focus is on the radial basis functions in the nucleus-centered multipole expansion of the model density. Based on the direct-space projection of the stockholder-partitioned quantum-c...
Article
A new computer program for post-processing analysis of quantum-chemical electron densities is described. The code can work with Slater- and Gaussian-type basis functions of arbitrary angular momentum. It has been applied to explore the basis-set dependence of the electron density and its Laplacian in terms of local and integrated topological proper...
Article
A new method for generating a compact multipolar representation of the electrostatic potential (EP) for flexible molecules is presented. The method is based on a constrained minimization of the difference between the quantum mechanical and the classical EP. The fitting procedure used adopts the least absolute shrinkage and selection operator techni...
Article
Various models applied to DFT structures and energies of 2-D and 3-D aromatic molecules shed new light on the effects of strain and aromaticity in these systems. The cyclic pi electron delocalisation does not stabilize the fullerene C60 formation; and 5-6 and 6-6 CC bonds have near-identical bond stretch potentials.
Article
A formalism is presented for the description of the electron density in a molecule or its fragment, using only a small number of parameters. The method is based on statistical analysis of a set of fragment electron densities obtained for a given quantum mechanical subsystem embedded in different environments (e.g., substituent groups, external fiel...

Network

Cited By