A5004066800- Spectroscopy and Quantum Chemical Studies
- Protein Structure and Dynamics
- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Ammonia Synthesis and Nitrogen Reduction
- Machine Learning in Materials Science
- Pancreatic function and diabetes
- Quantum, superfluid, helium dynamics
- Origins and Evolution of Life
- Enzyme Structure and Function
- Advanced Photocatalysis Techniques
- nanoparticles nucleation surface interactions
- Protein purification and stability
- Restraint-Related Deaths
- Neuroscience of respiration and sleep
- Electrochemical Analysis and Applications
- Nuclear Physics and Applications
- Fusion and Plasma Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Computational Drug Discovery Methods
- Thyroid Disorders and Treatments
- Fuel Cells and Related Materials
- Luminescence Properties of Advanced Materials
- Electronic and Structural Properties of Oxides
Czech Academy of Sciences, Institute of Organic Chemistry and Biochemistry
2018-2024
Charles University
2020-2023
It is well known in the field of machine learning that committee models improve accuracy, provide generalization error estimates, and enable active strategies. In this work, we adapt these concepts to interatomic potentials based on artificial neural networks. Instead a single model, multiple share same atomic environment descriptors yield an average outperforms its individual members as measure form disagreement. We not only use disagreement identify most relevant configurations build up...
Watching electrons swarm ammonia Liquid is unusual in its capacity to host stable solution, with vivid blue and bronze colors signifying the low- high-concentration regimes, respectively. Buttersack et al. used photoelectron spectroscopy accompanying theoretical simulations track precise energetic changes that ensued as steadily rising quantities of were introduced by dissolved lithium, sodium, or potassium (see Perspective Isborn). The results point a gradual transition from dilute...
Although machine learning potentials have recently had a substantial impact on molecular simulations, the construction of robust training set can still become limiting factor, especially due to requirement reference ab initio simulation that covers all relevant geometries system. Recognizing this be prohibitive for certain systems, we develop method transition tube sampling mitigates computational cost and model generation. In approach, generate classical or quantum thermal around path...
The oligomeric state of the storage form human insulin in pancreas, which may be affected by several endogenous components β-cell granules such as arginine, is not known. Here, effect arginine on oligomerization investigated independently protein crystallography, molecular dynamics simulations, and capillary electrophoresis. combined results point to a strong ionic strength assembly. Molecular simulations electrophoretic measurements at low/mM salt concentrations show no significant...
Photoelectron spectroscopy of microjets expanded into vacuum allows access to orbital energies for solute or solvent molecules in the liquid phase. Microjets water, acetonitrile and alcohols have previously been studied; however, it has unclear whether jets low temperature molecular solvents could be realized. Here we demonstrate a stable 20 μm jet ammonia (−60 °C) vacuum, which use record both valence core-level band photoelectron spectra using soft X-ray synchrotron radiation. Significant...
The benzene radical anion is an important intermediate in the Birch reduction of by solvated electrons liquid ammonia. Beyond organic chemistry, it intriguing subject spectroscopic and theoretical studies due to its rich structural dynamical behavior. In gas phase, species appears as a metastable shape resonance, while condensed remains stable. Here, we approach system ab initio molecular dynamics ammonia demonstrate that inclusion solvent crucial indeed leads stability. mere existence...
We report valence band photoelectron spectroscopy measurements of gas-phase and liquid-phase benzene as well those dissolved in liquid ammonia, complemented by electronic structure calculations. The origins the sizable gas-to-liquid-phase shifts electron binding energies deduced from spectral features are quantitatively characterized terms Born–Haber solvation model. This model also allows to rationalize observation almost identical ammonia despite fact that former solvent is polar while...
The benzene radical anion is a molecular ion pertinent to several organic reactions, including the Birch reduction of in liquid ammonia. species exhibits dynamic Jahn-Teller effect due its open-shell nature and undergoes pseudorotation geometry. Here, we characterize complex electronic structure this condensed-phase system based on ab initio dynamics simulations GW calculations solvated Using detailed analysis structure, find that spatial character excess electron follows underlying...
The benzene radical anion, well-known in organic chemistry as the first intermediate Birch reduction of liquid ammonia, exhibits intriguing properties from point view quantum chemistry. Notably, it has character a metastable shape resonance gas phase, while measurements solution find to be experimentally detectable and stable. In this light, our previous calculations performed bulk ammonia explicitly reveal that solvation leads stabilization. Here, we focus on transition anion an unstable...
We investigate the electronic structure of aromatic radical anions in solution phase employing a combination liquid-jet (LJ) photoelectron (PE) spectroscopy measurements and calculations. By using recently developed protocols, we accurately determine vertical ionization energies valence electrons both solvent solute molecules. In particular, first characterize pure tetrahydrofuran (THF) by LJ-PE conjunction with ab initio molecular dynamics simulations G0W0 Next, neutral naphthalene (Np)...
Aromatic compounds form an unusual kind of hydrogen bond with water and ammonia molecules, known as the $\pi$-hydrogen bond. In this work, we report ab initio path integral molecular dynamics simulations enhanced by machine-learning potentials to study structural, dynamical, spectroscopic properties solutions benzene in liquid ammonia. Specifically, model spatial distribution functions solvents around molecule, establish bonding interaction a prominent structural motive, set up existence...
<div> <p>The oligomeric state of the storage form human insulin in pancreas, which may be affected by several endogenous components beta-cells granules such as arginine, is not known. Here, effect arginine on oligomerisation investigated independently protein crystallography, molecular dynamics simulations and capillary electrophoresis. The combined results point to a strong ionic strength assembly. Molecular electrophoretic measurements at low/mM salt concentrations show no...
Although machine-learning potentials have recently had substantial impact on molecular simulations, the construction of a robust training set can still become limiting factor, especially due to requirement reference ab initio simulation that covers all relevant geometries system. Recognizing this be prohibitive for certain systems, we develop method transition tube sampling mitigates computational cost and model generation. In approach, generate classical or quantum thermal around path...
The oligomeric state of the storage form human insulin in pancreas, which may be affected by several endogenous components beta-cells granules such as arginine, is not known. Here, effect arginine on oligomerisation investigated independently protein crystallography, molecular dynamics simulations and capillary electrophoresis. combined results point to a strong ionic strength assembly. Molecular electrophoretic measurements at low/mM salt concentrations show no significant aggregation. In...