Publikacje
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wszystkich: 218
Katalog Publikacji
Rok 2020
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Total cross section measurements for electron scattering from tin(IV) chloride (SnCl4)
PublikacjaTotal cross section for electron scattering from SnCl4 molecules has been measured for energies from 0.6 to 300 eV. Obtained results have been compared with total cross sections for electron scattering from other tetrachloride molecules: XCl4 where X=C, Si, Ge.
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Theoretical and experimental study on scattering of low-energy electrons by dimethyl and diethyl ethers
PublikacjaWe report a joint theoretical and experimental investigation on low-energy electron scattering by dimethyl and diethyl ethers. The experimental elastic differential cross sections were measured at impact energies from 1 eV up to 30 eV and scattering angle range of 10◦ to 130◦. Theoretical elastic differential, integral and momentum-transfer cross sections are calculated at impact energies up to 30 eV, employing the Schwinger multichannel...
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Role of methylation in electron scattering on X(CH3)4 (X= C, Si, Ge) molecules (2)
PublikacjaTo investigate how replacement of H atom with methyl group (CH3) – in tetrahedral compounds of carbon, silicon and germanium – affects electron scattering process, total cross sections (TCS) for electron scattering from C(CH3)4, Si(CH3)4 and Ge(CH3)4 molecules have been compared with data for CH4, SiH4 and GeH4 molecules. All examined data have been obtained with the same experimental setup. The shape of all discussed TCS energy...
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Role of methylation in electron scattering on X(CH3)4 (X = C, Si, Ge) molecules
PublikacjaTotal cross sections (TCS) for low-energy electron scattering from X(CH3)4 (where X = C, Si, Ge) molecules have been measured using linear transmission method. Present results and those obtained previously for XH4 molecules were used to determine how methylation of the target is reflected in TCS energy dependence.
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Recent total cross section measurements in electron scattering from molecules
PublikacjaThe grand-total cross sections (TCSs) for electron scattering from a range of molecules, measured over the period 2009-2019 in various laboratories, with the use of different electron transmission systems, are reviewed. Where necessary, the presented TCS data are also compared to earlier results. Collection of investigated molecular targets (biomolecules, biofuels, molecules of technological application,hydrocarbons) reflects their...
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Polarimetric studies of L-arginine-doped potassium dihydrogen phosphate single crystals
PublikacjaConoscopic interference patterns, channelled spectra and polarimetric techniques have been used for the characterization of pure and doped (with L-arginine amino acid) potassium dihydrogen phosphate (KDP) single crystals. Experimental polarimetric data have been obtained for the frequently used wavelength of 633 nm and for two close wavelengths of 532 and 543 nm in a high-accuracy dual-wavelength polarimeter. The measurement of...
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Oddziaływanie elektronów z wybranymi prekursorami metalicznych i półprzewodnikowych nanostruktur wytwarzanych za pomocą skupionych wiązek elektronowych
PublikacjaPraca poświęcona jest oddziaływaniom elektronów z prostymi prekursorami metody FEBID. W szczególności wyznaczono oraz przeanalizowano całkowite przekroje czynne na rozpraszanie elektronów funkcji energii dla wybranych cząsteczek: SnCl4, TiCl4, C(CH3)4, Si(CH3)4 oraz Ge(CH3)4, C5H6. W ramach pracy badano korelacje pomiędzy wartościami całkowitych przekrojów czynnych, a wybranymi fizykochemicznymi wielkościami charakteryzującymi...
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Methylation effect in e−— scattering on methyl-substituted ethylenes
PublikacjaMethylation effect has been observed and studied in electron-scattering from selected hydrocarbon molecules. In measured total cross section (TCS) functions we have noticed energy shifts and changes in the intensity of observed structures.
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Low energy inelastic electron scattering from carbon monoxide: I. excitation of the a3Π, a’3Σ+ and AΠ1 electronic states.
PublikacjaDifferential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20◦ to 120◦. The normalization of the experimental cross sections...
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Low energy electron mass stopping power in H2
PublikacjaWe present experimental mass stopping powers of electrons in gaseous H2 obtained with a newly developed electron time-of-flight spectrometer, for the incident electron energy range of 10eV to 25eV. In our procedure the average energy loss is derived from our conversion of measured electron time-of-flight spectra into equivalent electron energy loss spectra so as to obtain the values of mass stopping power for electron scattering...
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Low energy elastic electron scattering from benzonitrile (C6H5CN)
PublikacjaWe present experimental differential elastic scattering cross sections (DCSs) for low energy electron scattering from benzonitrile along with integral and momentum-transfer cross sections that are determined from these DCSs. The measurements of DCSs are obtained using the relative flow method with helium as the standard gas, in a crossed electron-molecular gas beam arrangement. Our measurements are made at incident electron energies...
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Low energy differential elastic electron scattering from trichloromethane
PublikacjaExperimental differential cross sections for low energy electron scattering from trichloromethane is measured utilizing a crossed electron-molecular beam experiment via the relative flow method, for the incident electron energies in the range of E = 0.5 eV-30 eV and the scattering angles in the range of θ = 10◦ − 130◦ .
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Interaction of 4-nitrothiophenol with low energy electrons: Implications for plasmon mediated reactions
PublikacjaThe reduction of 4-nitrothiophenol (NTP) to 4-4′-dimercaptoazobenzene (DMAB) on laser illuminated noble metal nanoparticles is one of the most widely studied plasmon mediated reactions. The reaction is most likely triggered by a transfer of low energy electrons from the nanoparticle to the adsorbed molecules. Besides the formation of DMAB, dissociative side reactions of NTP have also been observed. Here, we present a crossed electron-molecular...
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Electron-impact ionization cross section calculations for selected ribonucleosides
PublikacjaTotal cross sections for the single electron-impact ionization of selected ribonuclosides (guanosine, adenosine, cytidine and uridine) have been calculated for electron energies ranging from the ionization threshold up to 5 keV.
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Electron-impact ionization cross section calculations for 5-chloropyridine and 5-bromopyridine molecules
PublikacjaThe total cross sections for the single electron-impact ionization of 5-chloropyridine (5-C5H4ClN) and 5-bromopyridine (5-C5H4BrN) molecules have been calculated using binary-encounter-Bethe method for electron energies ranging from the ionization threshold up to 5 keV.
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Electric and magnetic properties of Lanthanum Barium Cobaltite
PublikacjaThe cubic Ba0.5La0.5CoO3‐δ was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X‐ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low‐temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with θP = 198(3)...
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Dissociative electron attachment to benzoic acid (C7H6O2)
PublikacjaThe dissociative electron attachment (DEA) to benzoic acid (C6H5COOH) has been studied using an experimental crossed beam setup of a quadrupole mass spectrometer and a trochoidal electron monochromator. Relative partial cross sections for the DEA to produce negative ion fragments show the main channels for dissociation. The comparison of the present results with the ultraviolet photoelectron spectrum of benzoic acid [J. Meeks,...
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Dissociation of furan-2-carboxylic acid by low energy electrons
PublikacjaElectron attachment to molecular target can lead to a variety of negative fragment ions. We experi- mentally probe the main dissociative electron attachment channels in furan-2-carboxylic acid (C3H3O2 − COOH) - a molecular target composed of two important structural units: a furan ring and a carboxylic group. In our studies we utilise nearly mono-energetic electrons at electron energies from 0 eV up to 15 eV. Our detection setup...
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Dia- and paramagnetic contributions to magnetizabilities of relativistic hydrogenlike atoms in some low-lying discrete energy eigenstates
PublikacjaIn this paper we present tabulated data for relative diamagnetic and paramagentic contributions to the magnetizability ($\chi$) of the relativistic hydrogenlike atoms with a pointlike, motionless and spinless nucleus of charge $Ze$. Utilizing general analytical formulas for the diamagnetic ($\chi_{d}$) and paramagnetic ($\chi_{p}$) components of $\chi$, recently derived by us [P. Stefa{\'n}ska, 2020] with the aid of the Gordon...
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CROSS SECTIONS CALCULATIONS FOR ELECTRON SCATTERING FROM RHODANINE AND CYANOACETIC ACID
PublikacjaCross sections for electron-impact ionization and for elastic electron scattering for rhodanine (C3H3NOS2) and cyanoacetic acid (C3H3NO2) have been calculated in wide impinging electron energy range.
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Changes of Conformation in Albumin with Temperature by Molecular Dynamics Simulations
PublikacjaThis work presents the analysis of the conformation of albumin in the temperature range of 300K – 312K, i.e., in the physiological range. Using molecular dynamics simulations, we calculate values of the backbone and dihedral angles for this molecule. We analyze the global dynamic properties of albumin treated as a chain. In this range of temperature, we study parameters of the molecule and the conformational entropy derived from...
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Carboxylation Enhances Fragmentation of Furan upon Resonant Electron Attachment
PublikacjaWe report a dissociative electron attachment study to 2-furoic acid (C5H4O3) isolated in a gas phase, which is a model molecule consisting of a carboxylic group and a furan ring. Dissociation of furan by low energy electrons is accessible only via electronic excited Feshbach resonances at energies of incident electrons above 5 eV. On the other hand, carboxylic acids are well- known to dissociate via attachment of electrons at subexcitation energies....
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Analytical calculations of scattering lengths for a class of long-range potentials of interest for atomic physics
PublikacjaWe derive two equivalent analytical expressions for an $l$th partial-wave scattering length $a_{l}$ for central potentials with long-range tails of the form % \begin{math} \displaystyle V(r)=-\frac{\hbar^{2}}{2m}\frac{Br^{n-4}}{(r^{n-2}+R^{n-2})^{2}} -\frac{\hbar^{2}}{2m}\frac{C}{r^{2}(r^{n-2}+R^{n-2})}, \end{math} % ($r\geqslant r_{s}$, $R>0$). % For $C=0$, this family of potentials reduces to the Lenz potentials discussed in...
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An approach to constructing genuinely entangled subspaces of maximal dimension
PublikacjaGenuinely entangled subspaces (GESs) are the class of completely entangled subspaces that contain only genuinely multiparty entangled states. They constitute a particularly useful notion in the theory of entanglement but also have found an application, for instance, in quantum error correction and cryptography. In a recent study (Demianowicz and Augusiak in Phys Rev A 98:012313, 2018), we have shown how GESs can be efficiently...
Rok 2019
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Ultrazimne atomy od kuchni
PublikacjaArtykuł prezentuje w jaki sposób osiągnąć temperaturę bliską 0 K w laboratorium fizycznym. Krok po kroku opisane zostały procedury eksperymentalne używane do wytwarzania atomowego kondensatu Bose-Einsteina, m.in. chłodzenie laserowe, pułapkowanie magnetyczne, chłodzenie przez odparowanie.
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Storing Matter’technique in SIMS depth profile analysis
PublikacjaSecondary ion mass spectrometry (SIMS) is a very useful technique for the analysis of layered systems. It is based on the primary ion beam sputtering of solids and mass analysis of the emitted secondary ions. A main limitation of this technique results from the direct quantitative analysis, since the ionization efficiency of a given atom is highly influenced by the neighbouring atoms at the surface. This phenomenon is known as...
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Statistical properties of a modified standard map in quantum and classical regimes
PublikacjaWe present a model—a modified standard map. This model has interesting properties that allow quantum–classical correspondences to be studied. For some range of parameters in the classical phase space of this model, there exist large accelerator modes. We can create a family of maps that have large accelerator modes.
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Relativistic two-dimensional hydrogen-like atom in a weak magnetic field
PublikacjaA two-dimensional (2D) hydrogen-like atom with a relativistic Dirac electron, placed in a weak, static, uniform magnetic field perpendicular to the atomic plane, is considered. Closed forms of the first- and second-order Zeeman corrections to energy levels are calculated analytically, within the framework of the Rayleigh–Schrödinger perturbation theory, for an arbitrary electronic bound state. The second-order calculations are...
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Optical activity and electro-optic effect of l-arginine doped KDP single crystals
PublikacjaWe have used the modified polarimetric methods to study optical activity (OA) in the potassium dihydrogenphosphate (KDP) crystals doped with 0.7, 1.4 and 3.8 wt% L-arginine (L-arg) amino acid. Crystals were grown by the temperature reduction method. Small changes of the absolute eigen waves ellipticity and OA values in doped crystals were noted. We have experimentally determined the signs of OA in the [1 00] and [01 0] directions...
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Low to intermediate energy elastic electron scattering from dichloromethane (CH2Cl2)
PublikacjaWe report a theoretical-experimental investigation of electron scattering by dichloromethane (CH2Cl2) in the low- and intermediate energy ranges. Experimental elastic differential cross sections (DCS), in the incident electron energy range of 0.5-800 eV and scattering angle range of 10°–130°, were measured using a crossed beam relative flow technique. Integral and momentum- transfer cross sections were determined from the experimental...
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Low energy elastic scattering of electrons from hexafluoropropene (C3F6)
PublikacjaWe present cross sections from a joint experimental and theoretical study on elastic electron scattering from hexafluoropropene (C3F6) in the gas phase. The experimental results, using low energy electron spectroscopy, were obtained at incident electron energies of 0.5, 1, 1.5, 2, 3, 4, 5, 6, 10, 12, 15 and 20 eV, for scattering angles ranging from 10°to 130°. The theoretical method used in the computation of the integral, momentum...
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Formation of Protein Networks between Mucins: Molecular Dynamics Study Based on the Interaction Energy of the System
PublikacjaMolecular dynamics simulations have been performed for a model aqueous solution of mucin. As mucin is a central part of lubricin, a key component of synovial fluid, we investigate its ability to form cross-linked networks. Such network formation could be of major importance for the viscoelastic properties of the soft-matter system and crucial for understanding the lubrication mechanism in articular cartilage. Thus,the inter- and...
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Experimental determination of H2 mass stopping powers for low-energy electrons
PublikacjaWe present experimental mass stopping powers of electrons in gaseous H2 obtained with an electron time- of-flight spectrometer, for the incident electron energy range of 11 to 25 eV. In our procedure, the average energy loss is derived from conversion of the measured electron time-of-flight spectra into equivalent electron energy-loss spectra. Our present results are compared with the only available experimental measurement and...
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Entanglement of genuinely entangled subspaces and states: Exact, approximate, and numerical results
PublikacjaGenuinely entangled subspaces (GESs) are those subspaces of multipartite Hilbert spaces that consist only of genuinely multiparty entangled pure states. They are natural generalizations of the well-known notion of completely entangled subspaces, which by definition are void of fully product vectors. Entangled subspaces are an important tool of quantum information theory as they directly lead to constructions of entangled states,...
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Electron scattering from tin tetrachloride (SnCl4) molecules
PublikacjaAbsolute grand-total cross section (TCS) for electron scattering from a tin tetrachloride, SnCl4, molecule was measured at electron-impact energies ranging from 0.6 to 300 eV, in the linear electron-transmission experiment. The measured TCS energy dependence shows two very pronounced enhancements peaking near 1.2 eV and around 9.5 eV, separated with a deep minimum centered close to 3 eV. The low energy structure is attributed to...
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Electron collisions with X(CH3)4 molecules (X = C, Si, Ge)
PublikacjaAbsolute grand-total cross sections (TCSs) for electron scattering from tetramethylmethane [C(CH3)4], tetramethylsilane [Si(CH3)4], and tetramethylgermane [Ge(CH3)4] molecules have been measured at electron-impact energies extending from around 0.5 to 300 eV in the linear electron-transmission experiment. The measured TCS energy dependences show very pronounced broad enhancement, peaking near 5.5 eV for Si(CH3)4 and Ge(CH3)4 molecules...
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Elastic scattering of electrons from chloroform
PublikacjaWe present experimental and theoretical cross sections for elastic electron scattering from CHCl3. This is an important target because of its relevance to environmental chemistry and the plasma etching industry as a source of chlorine radicals. The experimental results were obtained at incident electron energies ranging from 0.5 to 800 eV in the 10deg-130deg scattering angle range. Theoretically, the scattering cross sections in...
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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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Cross sections for electron collision with pyridine [C5H5N] molecule
PublikacjaThe absolute grand -total cross section (TCS) for electron scattering from pyridine, C5H5N, molecules has been measured at impact energies from 0.6 to 300 eV in the linear electron-transmission experiment. The obtained TCS energy dependence appears to be typical for targets of high electric-dipole moment; the cross section generally decreases with rising energy, except for the 3–20 eV range, where a broad enhancement peaked near...
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Application of two-dimensional intensity maps in high-accuracy polarimetry
PublikacjaWe propose the analysis of 2D intensity contour maps which is based on the optical transmission function for the polarizer-specimen-analyzer system. A small modification of the high-accuracy universal polarimeter (HAUP) technique was used to measure the intensity maps (HAUP maps) and determine the phase retardation, linear dichroism (LD) parameters, and multiple light reflection contribution in uniaxial crystals. We have performed...
Rok 2018
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Two-dimensional hydrogen-like atom in a weak magnetic field
PublikacjaWe consider a non-relativistic two-dimensional (2D) hydrogen-like atom in a weak, static, uniform magnetic field perpendicular to the atomic plane. Within the framework of the Rayleigh-Schr¨odinger perturbation theory, using the Sturmian expansion of the generalized radial Coulomb Green function, we derive explicit analytical expressions for corrections to an arbitrary planar hydrogenic bound-state energy level, up to the fourth...
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Time-of-flight electron scattering from molecular hydrogen: Benchmark cross sections for excitation of the X1Σ+g→b3Σ+u transition
PublikacjaThe electron impact X1Σ+g to b3Σ+u transition in molecular hydrogen is one of the most important dissociation pathways to forming atomic hydrogen atoms, and is of great importance in modeling astrophysical and industrial plasmas where molecular hydrogen is a substantial constituent. Recently it has been found that the convergent close-coupling (CCC) cross sections of Zammit et al. [Phys. Rev. A 95, 022708 (2017)] are up to a factor...
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The Dynamical Projectors Method Hydro and Electrodynamics
PublikacjaThe dynamical projectors method proves to reduce a multicomponent problem to the simplest one-component problem with its solution determined by specific initial or boundary conditions. Its universality and application in many different physical problems make it particularly useful in hydrodynamics, electrodynamics, plasma physics, and boundary layer problems. A great variety of underlying mechanisms are included making this book...
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Static magnetic multipole susceptibilities of the relativistic hydrogenlike atom in the ground state: Application of the Sturmian expansion of the generalized Dirac-Coulomb Green function
PublikacjaWe study far- and near-field magnetic and electric multipole moments induced in the ground state of the Dirac one-electron atom placed in a weak 2L-pole magnetostatic field. The analysis is carried out within the framework of the first-order Rayleigh-Schrödinger perturbation theory, with the use of the Sturmian expansion of the generalized Dirac-Coulomb Green function [Szmytkowski, J. Phys. B 30, 825 (1997);J. Phys. B 30, 2747(E)...
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Second-order Stark effect and polarizability of a relativistic two-dimensional hydrogenlike atom in the ground state
PublikacjaThe second-order Stark effect for a planar Dirac one-electron atom in the ground state is analyzed within the framework of the Rayleigh-Schrödinger perturbation theory, with the use of the Sturmian series expansion of the generalized Dirac-Coulomb Green's function. A closed-form analytical expression for the static dipole polarizability of that system is found. The formula involves the generalized hypergeometric function ${}_{3}F_{2}$...
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Resonances and Dissociative Electron Attachment in HNCO
PublikacjaIn a combined experimental and theoretical study, we probe the dissociative electron attachment in isocyanic acid HNCO. The experimental absolute cross section for the NCO− fragment shows a sharp onset and fine structures near the threshold. The autoionizing state responsible for the dissociative attachment is found in both the R-matrix calculation and using analytic continuation in the coupling constant. The involved A' resonance...
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Physical crosslinking of hyaluronic acid in the presence of phospholipids in an aqueous nano-environment
PublikacjaHyaluronic acid and phospholipids are two components in the synovial joint cavity that contribute to joint lubrication synergistically. Molecular dynamics simulations were performed and hydrogen bonds in hyaluronic acid were analyzed to identify specific sites that are responsible for its physical cross-linking. Two molecular masses of hyaluronic acid, 10 kDa and 160 kDa, were considered. We use molecular dynamics simulations and...
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Nuclear magnetic shielding constants of Dirac one-electron atoms in some low-lying discrete energy eigenstates
PublikacjaWe present tabulated data for the nuclear magnetic shielding constants (σ) of the Dirac one-electron atoms with a pointlike, motionless and spinless nucleus of charge Ze. Utilizing the exact general analytical formula for σ derived by us (Stefańska, 2016) valid for an arbitrary discrete energy eigenstate, we have computed the numerical values of the magnetic shielding factors for the ground state and for the first and the second...
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Low-energy electron scattering from molecular hydrogen: Excitation of the X1Σg+ to b3Σu+ transition
PublikacjaWe present time-of-flight differential cross-section measurements and convergent close-coupling calculations of differential cross sections for the electron-impact excitation of the X 1 g + → b 3 u + transition in molecular hydrogen. A part of this work was recently published [M. Zawadzki et al., Phys. Rev. A 97, 050702(R) (2018)]. In this work, agreement between theory and experiment is excellent overall, and marks a transition...
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Low energy differential elastic electron scattering from acetonitrile (CH3CN)
PublikacjaMeasurements of elastic differential cross sections for electron scattering from acetonitrile (CH3CN) have been performed utilizing a crossed electron-molecular beam experiment and with the relative flow method, for the incident electron energy range of 0.7 eV–30 eV and the scattering angle range of 10◦–130◦. These differential cross sections have been used to calculate the elastic integral and momentum- transfer cross sections,...