Robert W. Góra

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Permanent need to understand nature, structure and properties of humic substances influences also separation methods that are in a wide scope used for fractionation, characterization and analysis of humic substances (HS). At the first glance techniques based on size-exclusion phenomena are the most useful and utilized for relating elution data to the(More)
A new approach for the analysis of intermolecular interactions in a solution is proposed. The changes in the interaction energy components due to the solvent effects are estimated on the basis of the interaction energy calculated in the presence of the electric field induced in a polarizable medium, or in the field of the effective fragment potentials.(More)
Twenty hydrogen-bonded complexes composed of nucleic acid base and amino acid side chain have been analyzed using ab initio quantum chemistry methods with the aim of gaining insights into the nature of molecular interactions in these systems. The intermolecular interaction energies were estimated using the second-order Møller-Plesset perturbation theory and(More)
We report the partitioning of the interaction-induced static electronic dipole (hyper)polarizabilities for linear hydrogen cyanide complexes into contributions arising from various interaction energy terms. We analyzed the nonadditivities of the studied properties and used these data to predict the electric properties of an infinite chain. The(More)
This work provides a comparison of neutral (H2O)2Ar(n) and negatively charged (H2O)(2-)Ar(n) complexes. The excess electron stabilizes the complexes and leads to the trans to cis rearrangement within the water dimer core. In the case of small complexes (n < or = 4) the microsolvation of the dimer by argon atoms arises on the trans side with respect to the(More)
The origins of stabilization in the short strong hydrogen bonds commonly referred to as "resonance-assisted" (RAHB) have been revisited using the modern valence-bond theory, the hybrid variational-perturbational interaction energy decomposition scheme and atoms in molecules (AIM) analysis. Dimers of carboxylic acids and amides have been chosen as the model(More)
2-Aminooxazole is generally considered to play a central role in the origin of informational polymers. In the current contribution we use density functional calculations to investigate the detailed mechanism of 2-aminooxazole formation from the prebiotic soup according to the scenario suggested by M. W. Powner, B. Gerland and J. D. Sutherland, Nature, 2009,(More)
Understanding the effects of ultraviolet radiation on nucleotides in solution is an important step towards a comprehensive description of the photochemistry of nucleic acids and their constituents. Apart from having implications for mutagenesis and DNA photoprotection mechanisms, the photochemistry of cytidines is a central element in UV-assisted syntheses(More)
The intermolecular hydrogen bonds in dimers of formic acid, acetic acid, and formamide were investigated. Additionally, three configurations of the pyrrole-2-carboxylic acid (PCA) dimer were studied to analyze how the pyrrole pi-electron system influences the carboxylic groups connected by double O-H...O hydrogen bonds. The ab initio calculations for the(More)
A well established method of direct injection of larger than conventional sample volumes ranging from 0.1 mL to 10 mL in HPLC is the injection valve method in which a loop of tubing is totally or partially filled with sample. Recent HPLC pumps have a flow-rate setting accuracy of +/- 1-2% over a flow-rate range from 0.1 mL/min to 10 mL/min and the flow(More)