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Prague, Czech Republic

A brief history of molecule counting in the last two centuries is described. The story started with early determinations of the Avogadro constant by Loschmidt and others and ends for the time being with its modern spectroscopic determinations. The relation of high-precision Avogadro constant measurements to modern metrology is discussed in the context of recent suggestions of reforms in the SI unit system. Source

The extracts of a homeopathic Chamomilla vulgaris preparation and chamomile tea were analyzed by surfaceenhanced Raman scattering and surface-enhanced IR spectroscopies. The aqueous or methanolic extracts were deposited on nanostructured, electrochemically prepared Au surfaces. Only saccharose was identified reliably in homeopathic sample. The presence of other component is evident but they could not be identified. Source

Muchova E.,Ustav fyzikalni chemie | Slavicek P.,Ustav fyzikalni chemie
Chemicke Listy

In this review pre-quantum atom and molecular models are briefly described. First we focus on the Bohr theory of one-electron and many-electron atoms as well as on the Bohr molecular theory. Further we describe the concepts of Newton, vortex atom models and various electron models, including those formed solely in the chemistry field. We show that even the incorrect scientific theories are inherent parts of intellectual history. Source

Hollas D.,Ustav fyzikalni chemie | Svoboda O.,Ustav fyzikalni chemie | Chmela J.,Ustav fyzikalni chemie | Slavicek P.,Ustav fyzikalni chemie
Chemicke Listy

The ultrafast dynamic processes initiated by ioni-zing radiation in water are discussed. At low photon energies, the primary processes are photoexcitation and photoionization. Both reaction channels ultimately lead to the formation of reactive species such as OH radical or solvated electron. Ejection of low-lying electrons initiate further electron processes such as the Auger decay or the recently identified intermolecular Coulomb decay. All these processes contribute to radiation damage of biomolecules. Novel experimental and theoretical methods used for the study of primary events in radiation chemistry of water are described. Source

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