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Chemistry as the key to understand the microuniverse

Theoretical work on metrological issues – SI units

Prof. Bogumił Jeziorski, PhD DSc [*]; Michał Lesiuk, PhD DSc, Assoc. Prof. and the team 

In 2019, the International System of Units (SI), which is a basis for accurate and reproducible measurements in science and technology, was fundamentally changed. It no longer relies on artifacts such as the platinum-irydium cylinder stored in Saint-Cloud (France), which used to serve as a prototype of the kilogram. Instead, in order to define the basic physical units, well-known atomic properties and fundamental laws of nature are used now. In particular, the energy of one joule and the temperature of one kelvin are strictly defined as multiples of the energy of a single photon emitted during a certain hyperfine transition in the cesium atom. The new definitions enable more accurate measurements of temperature and pressure — two fundamental quantities necessary in many fields of human activity, from the manufacturing of integrated circuits to aviation and navigation. The goal of our research is to develop theoretical models and computational software for accurate determination of atomic and molecular properties employed in temperature and pressure standards. The basic quantities of interest are electric and magnetic properties and noble atoms and parameters characterizing interaction of these atoms in vacuum and in laser fields. Theoretical calculations take into account subtle physical phenomena, such as relativistic effects, and enable the determination of properties of, e.g., helium gas with an accuracy better than one part per milion.

Selected publications:

  1. Rubin, I. Silander, C. Forssén, J. Zakrisson, E. Amer, D. Szabo, T. Bock, A. Kussicke, C. Günz, D. Mari, R.M. Gavioso, M. Pisani, D. Madonna Ripa, Z. Silvestri, P. Gambette, D. Bentouati, G. Garberoglio, M. Lesiuk, M. Przybytek, B. Jeziorski, J. Setina, M. Zelan, O. Axner, “Quantum-based realizations of the pascal’ status and progress of the empir-project: quantumpascal” Joint IMEKO TC3, T5, TC16 and TC22 International Conference, Cavtat-Dubrovnik, Croatia, 2022, DOI: 10.21014/tc16-2022.103
  2. Puchalski, K. Piszczatowski, J. Komasa, B. Jeziorski, K. Szalewicz, “Theoretical determination of the polarizability dispersion and the refractive index of helium” Phys. Rev. A 2016, 93, 032515, DOI: https://doi.org/10.1103/PhysRevA.93.032515
  3. Puchalski, K. Szalewicz, M. Lesiuk, B. Jeziorski, “QED calculation of the dipole polarizability of helium atom” Phys. Rev. A 2020, 101, 022505, DOI: https://doi.org/10.1103/PhysRevA.101.022505
Advancing Quantum Crystallography

Prof. Paulina Dominiak, PhD DSc; Prof. Krzysztof Woźniak, PhD DSc

Advances in science and technology, particularly, in chemistry, biology, medicine, pharmacy, mineralogy and materials science, rely on accurate information about the structures of chemical molecules and their assemblies. Crystallography is the most common method for determining 3D molecular structures. Over the past century, crystallographers have significantly improved crystallographic hardware, however, a century-old framework, spherical Independent Atom Model (IAM) of atomic electron density, still dominates in interpreting the diffraction/scattering data. IAM assumes that radiation scatters independently on atoms, treating them as isolated entities with no interactions or disturbances from chemical bonds or intermolecular interactions. Yet, it is evident that the experimental data we collect these days contains richer information than IAM can fully mimic.

Quantum crystallography (QCr) goes beyond IAM and merely determining atomic connectivity. It also supplies electronic parameters and  bridges the gap between theory and experiment in understanding the fundamental behaviour of matter at the molecular, atomic and subatomic levels.  QCr either provides more accurate  quantum-mechanical models to extract better-quality information on atomic structure from crystallographic data, or uses crystallographic data to enhance modelling of electronic structure of studied systems using either an electron density (charge and spin) or wave function based approaches. The resulting models constitute the basis for characterizing the nature of chemical bonds and quantifying the physicochemical properties of the studied sample.

Prof. Krzysztof Woźniak, Prof. Paulina Dominiak, Dr Michał Chodkiewicz and their younger colleagues are the world’s leading experts in the field of quantum crystallography. They are known from developments of such methods such as HAR, TAAM, MATTS data bank and dynamical QCr, and their implementations to single-crystal X-ray or electron diffraction, PDF analysis, as well applications in studying organic and inorganic crystals, minerals and proteins  or nucleic acids systems. They have also combined QCr with high pressure studies.

Selected publications:

  1. L. Chodkiewicz, R. Gajda, B. Lavina, S. Tkachev, V. B. Prakapenka, P. Dera, K. Woźniak,”Accurate crystal structure of ice VI from X-ray diffraction with Hirshfeld atom refinement” IUCrJ, 2022, 9, 573, DOI: https://doi.org/10.1107/S2052252522006662   IUCrJ Highlight
  2. L. Chodkiewicz, M. Woińska, K. Woźniak, „Hirshfeld atom like refinement with alternative electron density partitions” IUCrJ, 2020, 7, 1199, DOI: https://doi.org/10.1107/S2052252520013603
  3. Gajda, D. Zhang, J. Parafiniuk, P. Dera, K. Woźniak, „Tracing electron density changes in langbeinite under pressure„, IUCrJ, 2022, 9, 146, DOI: https://doi.org/10.1107/S2052252521012628
  4. Stachowicz, R. Gajda, J. Parafiniuk, A. Makal, S. Sutuła, P. Fertey, K. Woźniak, „Charge Density Redistribution With Pressure in Hsianghualite„, Scientific Reports 2023, 13 1609, DOI: https://doi.org/10.1038/s41598-023-28350-4
  5. K. Jha, B. Gruza, P. Kumar, M. L. Chodkiewicz, P. M. Dominiak, “TAAM: a reliable and user friendly tool for hydrogen-atom location using routine X-ray diffraction data” Acta Crystallogr. B 2020, 76, 296, DOI: https://doi.org/10.1107/S2052520620002917
  6. Gruza, M. L. Chodkiewicz, J. Krzeszczakowska, P. M. Dominiak, “Refinement of organic crystal structures with multipolar electron scattering factors” Acta Crystallogr. A 2020, 76, 92, DOI: https://doi.org/10.1107/S2053273319015304
  7. M. Rybicka, M. Kulik, M. L. Chodkiewicz, P. M. Dominiak, “Multipolar atom types from theory and statistical clustering (MATTS) data bank: impact of surrounding atoms on electron density from cluster analysis” J. Chem. Inf. Model., 2022, 62, 3766, DOI: https://pubs.acs.org/doi/10.1021/acs.jcim.2c00145
  8. A. Budniak, N. K. Karolak, M. Kulik, K. Młynarczyk, M. W. Górna, P. M. Dominiak “The role of electrostatic interactions in IFIT5-RNA complexes predicted by the UBDB+EPMM method” J. Phys. Chem. B., 2022, 126, 9152, DOI: https://pubs.acs.org/doi/10.1021/acs.jpcb.2c04519
  9. A. Hoser, M. Sztylko, D. Trzybiński, A. Ø. Madsen, “Theoretically derived thermodynamic properties can be improved by the refinement of low-frequency modes against X-ray diffraction data” Chem. Comm. 2021, 57, 9370, DOI: https://doi.org/10.1039/D1CC02608A
  10. Zwolenik, D. Tchoń, A. Makal, “Evolution of structure and spectroscopic properties of a new 1,3-di­acetylpyrene polymorph with temperature and pressure” IUCrJ 2024, 11, 519, DOI: https://doi.org/10.1107/S2052252524003634
  11. Tchoń and A. Makal, “Maximizing completeness in single-crystal high-pressure diffraction experiments: phase transitions in 2oAP” IUCrJ 2021, 8, 1006, DOI: https://doi.org/10.1107/S2052252521009532