Wyniki wyszukiwania dla: physical and chemical
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Oxidizing CO2 with superhalogens
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The quantum free energy barrier for hydrogen vacancy diffusion in Na3AlH6
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Dissociative electron attachment to HGaF4 Lewis–Brønsted superacid
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Mechanisms of carbon monoxide hydrogenation yielding formaldehyde catalyzed by the representative strong mineral acid, H2SO4, and Lewis–Brønsted superacid, HF/AlF3
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Elastic moduli of biological fibers in a coarse-grained model: crystalline cellulose and β-amyloids
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Reactivity induced at 25 K by low-energy electron irradiation of condensed NH3-CH3COOD (1:1) mixture
PublikacjaW wyniku bombardowania niskoenergetycznymi elektronami skondensowanej mieszaniny kwasu octowego (CH3COOD) i amoniaku (NH3) następuje synteza najprostszego aminokwasu - glicyny - bez potrzeby dodatkowej aktywacji termicznej. Filmy molekularne przed i po bombardowaniu elektronami były badane techniką HREELS.
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Electron attachment and electron iozization of acetic acid clusters embedded in helium nanodroplets
PublikacjaThe effect of incident electrons on acetic acid clusters is explored for the first time. The acetic acid clusters are formed inside liquid helium nanodroplets and both cationic and anionic productsejected in to the gas phase aredetected by mass spectrometry.
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Visible-light-induced photocatalysis through surface Plasmon excitation of gold on titania surfaces
PublikacjaPietnascie komercyjnych probek tlenku tytanu(IV) zostalo zmodyfikowanych zlotem za pomoca fotodepozycji oraz scharakteryzowanych. Fotoaktywnosci proszkow Au/TiO2 zostaly przebadane dla fotodegradacji kwasu octowego i 2-propanolu podczas naswietlania promieniowaniem widzialnym oraz ultrafioletowym. Wykazano, ze fotokatalityczne aktywnosci scisle zaleza od wlasciwosci nanoczastek zlota i tlenku tytanu. Analizy spektrum działania...
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A XAS study of a highly diluted Pt electrocatalyst operating in PEM fuel cells
PublikacjaWe present an X-ray absorption spectroscopy (XAS) study of a low Pt content catalyst layer(Pt loading 0.1 mg c2) operating at the cathode of a proton exchange membrane fuel cell(PEMFC). This catalyst is based on the use of a mesoporous inorganic matrix as a support forthe catalyst Pt nanoparticles. Due to the high Pt dilution, in situ measurements of itsstructural properties by XAS are challenging and suitable experimental strategies...
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Hydrophobic hydration and pairwise hydrophobic interaction of Lennard-Jones and Mie particles in different water models
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Radiative lifetime of a BODIPY dye as calculated by TDDFT and EOM-CCSD methods: solvent and vibronic effects
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Energy levels in CaWO4:Tb3+ at high pressure
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Comparison of quenching mechanisms in Gd3Al5−xGaxO12:Ce3+ (x = 3 and 5) garnet phosphors by photocurrent excitation spectroscopy
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Temperature effect on the emission spectra of narrow band Mn4+phosphors for application in LEDs
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Spectroscopic properties and location of the Tb3+ and Eu3+ energy levels in Y2O2S under high hydrostatic pressure
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Spectroscopic properties and location of the Ce3+ energy levels in Y3Al2Ga3O12 and Y3Ga5O12 at ambient and high hydrostatic pressure
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Reply to the ‘Comment on “Spectroscopic properties and location of the Ce3+ energy levels in Y3Al2Ga3O12 and Y3Ga5O12 at ambient and high hydrostatic pressure”’ by Y. Wang, M. Głowacki, M. Berkowski, A. Kamińska and A. Suchocki, Phys. Chem. Chem. Phys., 2019, 21, DOI: 10.1039/C8CP06154H
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Study of persistent luminescence and thermoluminescence in SrSi2N2O2:Eu2+,M3+(M = Ce, Dy, and Nd)
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Spectroscopic properties of high-temperature sintered SrS:0.05%Ce3+ under high hydrostatic pressure
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Spectroscopic properties and location of the Tb3+ and Eu3+ energy levels in Y2O2S under high hydrostatic pressure
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Creation of mesopores in carbon nanotubes with improved capacities for lithium ion batteries
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Dynamics and stability of icosahedral Fe–Pt nanoparticles
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Superconductivity in CaBi2
PublikacjaSuperconductivity is observed with critical temperature Tc = 2.0 K in self-flux-grown single crystals of CaBi2. This material adopts the ZrSi2 structure type with lattice parameters a = 4.696(1) Å, b = 17.081(2) Å and c = 4.611(1) Å. The crystals of CaBi2 were studied by means of magnetic susceptibility, specific heat and electrical resistivity measurements. The heat capacity jump at Tc is DC/gTc = 1.41, confirming bulk superconductivity;...
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Unique agreement of experimental and computational infrared spectroscopy: a case study of lithium bromide solvation in an important electrochemical solvent
PublikacjaInfrared (IR) spectroscopy is a widely used and invaluable tool in the studies of solvation phenomena in electrolyte solutions. Using state-of-the-art chemometric analysis of a spectral series measured in a concentration-dependent manner, the spectrum of the solute-affected solvent can be extracted, providing a detailed view of the structural and energetic states of the solvent molecules influenced by the solute. Concurrently,...
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How water mediates the long-range interactions between remote protein molecules
PublikacjaThe high crowding of macromolecules in the cytoplasm affects the processes that occur inside a living cell. It can, for example, promote the forming of various loosely connected structures of proteins. It also means that bulk water is, essentially, not present there. The relatively thin layer of solvent that separates macromolecules may be able to participate in the long-range interactions between them and make them respond to...
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Modelling charge transfer processes in C2+ -tetrahydrofuran collision for ion-induced radiation damage in DNA building blocks
PublikacjaInvestigations of collision-induced processes involving carbon ions and molecules of biological interest in particular DNA building blocks, are crucial to model the effect of radiation on cells in order to improve medical treatments for cancer therapy. Using carbon ions appears to be one of the most efficient ways to increase biological effectiveness to damage cancerous cells by irradiating deep-seated tumors. Therefore, interest...
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Dissociative electron attachment and anion-induced dimerization in pyruvic acid
PublikacjaWe report partial cross sections for the dissociative electron attachment to pyruvic acid. A rich fragmentation dynamics is observed. Electronic structure calculations facilitate the identification of complex rearrangement reactions that occur during the dissociation. Furthermore, a number of fragment anions produced at electron energies close to 0 eV are observed, that cannot originate from single electron-molecule collisions....
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Multicomponent ionic liquid CMC prediction
PublikacjaWe created a model to predict CMC of ILs based on 704 experimental values published in 43 publications since 2000. Our model was able to predict CMC of variety of ILs in binary or ternary system in a presence of salt or alcohol. The molecular volume of IL (Vm), solvent-accessible surface (Sˆ), solvation enthalpy (DsolvGN), concentration of salt (Cs) or alcohol (Ca) and their molecular volumes (Vms and Vma, respectively) were chosen...
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Electronic structure and time-dependent description of rotational predissociation of LiH
PublikacjaThe adiabatic potential energy curves of the ^1Sigma+ and ^1Pi states of the LiH molecule were calculated. They correlate asymptotically to atomic states, such as 2s + 1s, 2p + 1s, 3s + 1s, 3p + 1s, 3d + 1s, 4s + 1s, 4p + 1s and 4d + 1s. A very good agreement was found between our calculated spectroscopic parameters and the experimental ones. The dynamics of the rotational predissociation process of the 1^1Pi state were studied...
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Characteristics of hydration water around hen egg lysozyme as the protein model in aqueous solution. FTIR spectroscopy and molecular dynamics simulation
PublikacjaW niniejszej pracy przedstawiono wyniki badań dotyczące hydratacji białka modelowego - lizozymu z jaja kurzego w roztworze wodnym. Wiodącą techniką stosowaną w badaniach była spektroskopia oscylacyjna FTIR z zastosowaniem techniki rozcieńczenia izotopowego wody półciężkiej HDO w roztworze wody zwykłej. Analiza widma HDO przy pomocy "metody widm zaburzonych" pozwoliła na wyizolowanie widma wody zaburzonej przez lizozym, a tym samym...
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Interaction of cisplatin and two potential antitumoral platinum(ii) complexes with a model lipid membrane: a combined NMR and MD study
PublikacjaIn this study, the interaction of cisplatin (1) and two potential antitumoral Pt(II) complexes (2 and 3) with a model DMPC bilayer was investigated by multinuclear NMR spectroscopy and MD simulations in order to understand its implication for the different antitumoral properties shown by the three complexes. In particular, 31P, 13C and 2H solid state NMR experiments were performed to obtain information on the phase structure, phase...
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The importance of the shape of the protein-water interface of a kinesin motor domain for dynamics of the surface atoms of the protein
PublikacjaSingle kinesin motor domain immersed in water has been investigated using molecular dynamics. It has been found that local properties of water in solvation shell change along with the nature of neighboring protein surface. However, a detailed analysis leads to the conclusion that the geometrical features of hydrogen bonds and overall structure of kinesin hydration water is not very different from bulk water. The local values of...
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Limonene: electronic state spectroscopy by high-resolution vacuum ultraviolet photoabsorption, electron scattering, He(I) photoelectron spectroscopy and ab initio calculations
PublikacjaZbadano limonen metodami spektroskopii absorpcyjnej, elektronowej, fotojonizacyjnej. Wyniki porównano z obliczeniami ab initio. Otrzymano strukturę wibracyjną molekuły.
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Defect engineering, microstructural examination and improvement of ultrafast third harmonic generation in GaZnO nanostructures: a study of e-beam irradiation
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Raman spectroscopic study of Ni2+-DNA interactions in aqueous systems
PublikacjaMetodą ramanowskich widm różnicowych określono sposób oddziaływania jonu Ni2+ z DNA(CT) w układach wodnych. Kation Ni(II) koordynuje w pozycjach N7 guaniny (G) i adeniny (A) w powtarzających się sekwencjach GG, AA i GA cząsteczki DNA. Jednocześnie Ni2+ oddziałuje zewnątrz sferowo poprzez cząsteczki wody z grupami fosforanowymi DNA.
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Preferential solvation in (amide+alcohol) binary mixtures. Part 2. The N-methylpyrrolidinone+methanol mixture at T = 313.15 K: thermodynamic resultsand molecular dynamics calculations.
PublikacjaBadano zjawisko preferencyjnej solwatacji amidu (N-metylopyrrolidonu) przez metanol wykorzystując dwie uzupełniające się metody: bezpośrednich pomiarów własności termodynamicznych roztworu oraz symulacji komputerowych. W metodzie pierwszej dokonano pomiarów wielkości termodynamicznych takich jak: nadmiarowa energia swobodna mieszania, nadmiarowa objętość mieszania oraz współczynnika ściśliwości izotermicznej mieszaniny,...
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Preferential solvation in (amide+alcohol) binary mixtures. Part 1. The N- methylpyrrolidinone+ethanol mixture at T = 313.15 K: thermodynamic resultsand molecular dynamics calculations.
PublikacjaBadano zjawisko preferencyjnej solwatacji amidu (N-metylopyrrolidonu) przez etanol wykorzystując dwie uzupełniające się metody: bezpośrednich pomiarów własności termodynamicznych roztworu oraz symulacji komputerowych. W metodzie pierwszej dokonano pomiarów wielkości termodynamicznych takich jak: nadmiarowa energia swobodna mieszania, nadmiarowa objętość mieszania oraz współczynnika ściśliwości izotermicznej mieszaniny,...
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Water-mediated influence of a crowded environment on internal vibrations of a protein molecule
PublikacjaThe influence of crowding on the protein inner dynamics is examined by putting a single protein molecule close to one or two neighboring protein molecules. The presence of additional molecules influences the amplitudes of protein fluctuations. Also, a weak dynamical coupling of collective velocities of surface atoms of proteins separated by a layer of water is detected. The possible mechanisms of these phenomena are described....
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Application of the tetraphenylphosphonium tetraphenylborate (TPTB) assumption to the thermodynamic properties of solvated ions in dimethylsulfoxide
PublikacjaW niniejszej pracy za pomocą spektroskopii ATR FTIR sprawdzano możliwość zastosowania tetrafenyloboranu tetrafenylofosfoniowego w metodzie elektrolitu wzorcowego, służącej do podziału wielkości termodynamicznych elektrolitów w dimetylosulfotlenku na udziały jonowe. Jednoznacznie stwierdzono, że poza termodynamiczne założenie o identycznych oddziaływaniach jonów w elektrolicie wzorcowym z cząsteczkami DMSO jest nieprawdziwe. Uzyskane...
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Tuning the work function of graphite nanoparticles via edge termination
PublikacjaGraphite nanoparticles are important in energy materials applications such as lithium-ion batteries (LIBs), supercapacitors and as catalyst supports. Tuning the work function of the nanoparticles allows local control of lithiation behaviour in LIBs, and the potential of zero charge of electrocatalysts and supercapacitors. Using large scale density functional theory (DFT) calculations, we find that the surface termination of multilayer...
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Water uptake and energetics of the formation of barium zirconate based multicomponent oxides
PublikacjaA group of multi-component oxides based on BaZrO3 have been prepared using a solid-state reaction method and examined in terms of their water uptake and thermodynamics of formation. Depending on the type and amount of acceptor substitution, the synthesized compounds exhibit various proton defect concentrations, reaching up to 0.2 mol/mol for a compound containing 10 different elements in the B-sublattice, where 50% of them are...
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Two-body dissociation of isoxazole following double photoionization – an experimental PEPIPICO and theoretical DFT and MP2 study
PublikacjaThe dissociative double photoionization of isoxazole molecules has been investigated experimentally and theoretically. The experiment has been carried out in the 27.5–36 eV photon energy range using vacuum ultraviolet (VUV) synchrotron radiation excitation combined with ion time-of-flight (TOF) spectrometry and photoelectron–photoion–photoion coincidence (PEPIPICO) technique. Five wellresolved two-body dissociation channels have...
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Proton conductivity in multi-component ABO4-type oxides
PublikacjaThis work investigates how configurational entropy in oxides could affect proton conductivity. For this purpose, three samples of different elemental compositions are synthesized. Five, six and seven elements were introduced into the A-site of ANbO4, forming La1/5 Nd1/5 Sm1/5Gd1/5 Eu1/5NbO4, La1/6Nd1/6Sm1/6Gd1/6Eu1/6Ho1/6NbO4 and La1/7Nd1/7Sm1/7Gd1/7Eu1/7Ho1/7Er1/7NbO4, respectively. The high configuration disorder changes the...
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Influence of temperature and interactions with ligands on dissociation of dsDNA and ligand-dsDNA complexes of various types of binding : an electrochemical study.
PublikacjaSeveral medicinally important compounds that bind to dsDNA strands via intercalation (C-1311, C-1305, EtBr), major groove binding (Hoechst 33258) and covalent binding (cis-Pt) were examined. The obtained results suggest that both the transfer of conformation B to C and the denaturation process, for the ligand-dsDNA complexes, except for covalently bound cis-Pt, took place at higher temperatures compared to the unbound helix. Furthermore,...
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Dissociative ionization dynamics of dielectric gas C3F7CN
PublikacjaFluoronitrile C3F7CN is a promising candidate for the replacement of SF6 dielectric gas in high-voltage insulation. We present a combined experimental and theoretical study on its ionization dynamics probed in the 0-100 eV energy range. We exploited the total ion collection technique to determine the absolute ionization cross section, mass spectrometry to determine the fragment branching ratios and ab initio nonadiabatic molecular...
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Excited state properties of a series of molecular photocatalysts investigated by time dependent density functional theory.
PublikacjaTime dependent density functional theory calculations are applied on a series of molecular photocatalysts of the type [(tbbpy)2M1(tpphz)M2X2]2+ (M1 = Ru, Os; M2 = Pd, Pt; X = Cl, I) in order to provide information concerning the photochemistry occurring upon excitation of the compounds in the visible region. To this aim, the energies, oscillator strengths and orbital characters of the singlet and triplet excited states are investigated....
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Why is the cubic structure preferred in newly formed ice?
PublikacjaMolecular dynamics was employed to explain the preference for the cubic structure in newly formed crystals of ice. The results showed that in supercooled liquid water the molecules connected by hydrogen bonds are more likely to adopt relative orientations similar to the ones characteristic for cubic ice. The observed preference for certain relative orientations of molecules in the hydrogen-bonded pairs results in the higher probability...
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Properties of water in the region between a tubulin dimer and a single motor head of kinesin
PublikacjaA kinesin is a molecular motor that can perform movement on a microtubule track in a stepping-like manner. This motion is connected with processes of association and dissociation of kinesin and tubulin. Water is an important participant in these kinds of molecular interactions. This is why we have decided to investigate the dynamical and structural properties of water in the region between the kinesin catalytic domain and the tubulin...
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Effect of osmolytes on the thermal stability of proteins: replica exchange simulations of Trp-cage in urea and betaine solutions
PublikacjaAlthough osmolytes are known to modulate the folding equilibrium, the molecular mechanism of their effect on thermal denaturation of proteins is still poorly understood. Here, we simulated the thermal denaturation of a small model protein (Trp-cage) in the presence of denaturing (urea) and stabilizing (betaine) osmolytes, using the all-atom replica exchange molecular dynamics simulations. We found that urea destabilizes Trp-cage...
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On the relationship between the structural and volumetric properties of solvated metal ions in O-donor solvents using new structural data in amide solvents
PublikacjaThe structures of the N,N-dimethylformamide (dmf), N,N-dimethylacetamide (dma), and N,N-dimethylpropionamide (dmp) solvated strontium and barium ions have been determined in solution using large angle X-ray scattering and EXAFS spectroscopy. The strontium ion has a mean coordination number (CN) between 6.2 and 6.8, and the barium ion has a mean CN between 7.1 and 7.8 in these amide solvents. The non-integer numbers indicates that...