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Cross sections for ionization and ionic fragmentation of pyrimidine molecules by electron collisions
PublicationThe electron impact mass spectroscopy and the total ion collection measurements were used to investigate the ionization and ionic fragmentation of the pyrimidine, C4H4N2, molecules in the gasphase. The cation mass spectra were measured in the 10−85 amu range and the observed mass peaks assigned to corresponding ionic fragments. The most abundant cation in the mass spectra is the parent cation, C4H4N+2, at 80 amu. The appearance...
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Electron ionization and low energy electron attachment to molecules of biological interest
PublicationEthylenediaminetetraacetic acid (EDTA) and 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) were investigated by electron impact ionization and low energy electron attachment. Both compounds are components of biological buffers and often are used as DNA stabilizers in irradiation studies. hus it is of a great importance to understand their potential interactions with radiation. Our results revealed that at least one of them, EDTA, may...
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Electron impact fragmentation of pyrrole molecules studied by fluorescence emission spectroscopy
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Fragmentation of isoxazole molecules by electron impact in the energy range 10–85eV
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Electron ionization and low energy electron attachment to molecules of biological interest
PublicationEthylenediaminetetraacetic acid (EDTA) and 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS) were investigated by electron impact ionization and low energy electron attachment. Both compounds are components of biological buffers and often are used as DNA stabilizers in irradiation studies. hus it is of a great importance to understand their potential interactions with radiation. Our results revealed that at least one of them, EDTA, may...
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Molecular Dynamics Study of the Internal Water Molecules in Vasopressin and Oxytocin Receptors
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Stable anions formed by organic molecules substituted with superhalogen functional groups
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Electron scattering from hexafluoroacetone molecules: cross section measurements and calculations
PublicationZmierzono absolutne całkowite przekroje czynne na zderzenie elektronów z drobinami hexafluoroacetonu (HFA). Pomiary przeprowadzono dla energii zderzenia od 1 do 400 eV. Zależność energetyczna przekroju czynnego wykazała obecność struktur związanych z procesami o charakterze rezonansowym. Wykonano obliczenia sprężystego i jonizacyjnego przekroju czynnego dla drobin HFA i acetonu. Suma obliczonych przekrojów wykazuje dużą zgodność...
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Cross sections for electron scattering from furan molecules; measurements and calculations
PublicationZmierzono i policzono przekroje czynne (TCS) na rozproszenie elektronów na drobinach furanu (C4H4O). Całkowite przekroje czynne zmierzono metodą transmisyjną w zakresie energii 0.6 - 400 eV. Sprężysty i jonizacyjny przekrój czyny obliczono dla energii zderzenia do 4 keV; powyżej 70 eV suma obu przekrojów pozostaje w dobrej zgodności z mierzonymi wartościami TCS.
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Electron-scattering total cross sections for triatomic molecules: NO2 and H2O
PublicationZmierzono całkowite przekroje czynne na rozpraszanie elektronów na drobinach NO2 i H2O, odpowiednio w zakresie energii od 3 do 370 eV oraz 0,5 do 370 eV. Dla średniej energii zderzenia obliczono ponadto przekroje na rozproszenie sprężyste i jonizację.
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Excited states of isoxazole molecules studied by electron energy-loss spectroscopy
PublicationElectron energy-loss spectra were measured in isoxazole in the excitation energy range 3.5−10 eV to investigate the valence excited states. Spectra recorded at different scattering conditions enabled the identification of the singlet and triplet states and the determination of their vertical excitation energies. The two lowest energy triplet bands, ππ* 13A' and ππ* 23A' at 4.20 and 5.30 eV, respectively show vibrational progressions....
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Formation of CN (B2∑+) radicals in the vacuum-ultraviolet photodissociation of pyridine and pyrimidine molecules
PublicationFormation of the excited CN(B2∑+) free radicals in the photodissociation of pyridine (C5H5N) and pyrimidine (C4H4N2) molecules was investigated over the energy ranges 16–27 and 14.7–25 eV, respectively. Photon-induced fluorescence spectroscopy was applied to detect the vibrationally and rotationally excited CN radicals by recording the B2∑+→X2∑+ emission bands (violet system). The measured dissociation yield curves demonstrate...
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Annihilation rates of low-energy positron scattering from simple diatomic molecules
PublicationWe discuss the calculations of Zeff coefficients for a series of diatomic molecules over the range of energies below the positronium formation. During the development of a general code for polyatomic, nonlinear molecules colliding with positrons, it was discovered that the earlier one, employed only for diatomic molecules, had an error. The error is corrected and the corrected results are presented here. We also discuss a way of...
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Hydrogen migration in formation of NH(A3Π) radicals in photodissociations of isoxazole and pyridine molecules
PublicationIn the present study, the H atom migration was observed in the photodissociation processes of the isoxazole and pyridine molecules in the gas-phase, applying the photon-induced fluorescence spectroscopy (PIFS).
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Electron collisions with X(CH3)4 molecules (X = C, Si, Ge)
PublicationAbsolute 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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How water mediates the long-range interactions between remote protein molecules
PublicationThe 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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Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules
PublicationWe present correlation-polarization potentials for the calculation of scattering cross sections of positrons with atoms and molecules. The potentials are constructed from a short-range correlation term and a long-range polarization term. For the short-range correlation term we present four different potentials that are derived from multi-component density functionals. For the long-range polarization term we employ a multi-term...
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Formation of CN (B2Σ+) radicals in the vacuum-ultraviolet photodissociation of pyridine and pyrimidine molecules
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Calculation of Vibrational Resonance Raman Spectra of Molecules Using Quantum Chemistry Methods
PublicationThe understanding and interpretation of experimental resonance Raman (RR) spectra can strongly benefit from theoretical simulations. These can be achieved by combining quantum chemistry (QC) methods to calculate the electronic and vibrational molecular properties, together with appropriate models and approximations to compute the Raman intensities. This chapter presents the main and most commonly employed approaches to calculate...
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Exploring Solanum tuberosum Epoxide Hydrolase Internal Architecture by Water Molecules Tracking
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Review of the applicability of ionic liquid matrices for the quantification of small molecules by MALDI MS
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Non-parametric application of Tsallis statistics to systems consisting of M hydrogen molecules
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Total electron-scattering cross section measurements for tetrahydropyran, (CH2)5O, molecules
PublicationZmierzono całkowity przekrój czynny (TCS) na rozproszenie elektronów na drobinach tetrahydropyranu. Pomiary przeprowadzono metodą transmisyjną w zakresie energii zderzenia 1 - 400 eV. Otrzymana zależność energetyczna TCS wskazuje na obecność procesów rezonansowych w zakresie 3 - 15 eV. Wyniki porównano z całkowitymi przekrojami czynnymi dla drobin tetrahydrofuranu i alkoholu alfa-tetrahydrofurfurylowego.
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Fragmentation of isoxazole molecules by electron impact in the energy range 10-85 eV
PublicationBadano fragmentację cząsteczek isoxazolu w zderzeniach z elektronami metodą wzbudzenia optycznego. Obserwowano linie wzbudzonego wodoru z serii Balmera oraz pasma emisyjne fragmentów CH oraz CN. Zmierzono bezwzględne wartości emisyjnych przekrojów czynnych.
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Electron-scattering total cross sections for complex molecules: group additivity rule
PublicationZaprezentowano całkowite przekroje czynne na rozpraszanie elektronów na dwóch rodzinach drobin: pierwszej - zawierającej azot jako atom centralny [N(CH3)3, NH2CH3, NH3]oraz drugiej - rodzinę eterów cyklicznych [c-(CH2)nO, gdzie n=2-5]. Zostało pokazane, że TCS dla niektórych drobin wieloatomowych można wyznaczyć na podstawie wyników TCS dla drobin o prostszej budowie lub ich fragmentów.
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Fluctuation-enhanced sensing: electronic dog nose identifies odors and counts molecules.
PublicationPrzedstawiono koncepcję wykrywania mieszanin gazów za pomocą analizy fluktuacji rezystancji sensora gazu. Porównano proponowaną ideę do wykorzystywanej w naturze przez zmysł węchu, w którym do mózgu dociera szereg pojedynczych impulsów elektrycznych wywołujących odczuwane wrażenie zapachowe.
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Cross sections for electron scattering from sulfuryl chloride fluoride (SO2ClF) molecules
PublicationArtykuł prezentuje zmierzone całkowite przekroje czynne oraz obliczone sprężyste i jonizacyjne przekroje czynne na rozpraszanie elektronów na drobinach SO2ClF dla niskich i średnich energii zderzenia. Wyniki porównano z dostępnymi przekrojami czynnymi dla drobin zawierających siarkę jako atom centralny.
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Influence of diffusion on nonradiative energy transfer between FMN molecules in aqueous solution
PublicationZmierzono zależności wydajności kwantowej roztworów wodnych FMN w zakresie koncentracji od 6,31x10^-5 do 1,8x10^-2 M w temperaturach 298,2 i 323,9 K. Otrzymane wyniki porównano z analogicznymi, uzyskanymi teoretycznie na podstawie modelu nie biorącego i biorącego pod uwagę dyfuzję molekuł fluoroforu. Porównanie wykazuje, że dla badanych roztworów dyfuzja nie może być pominięta, oraz, że dla uzyskania zgodności otrzymanych wyników...
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Effect of urea and glycine betaine on the hydration sphere of model molecules for the surface features of proteins
PublicationWater properties may significantly affect protein stability. Osmolytes are compounds that intrinsically affect water in many different ways and thus can influence proteins with this type of indirect mechanism. In this study, we characterize water properties in ternary solutions: model–water–osmolyte, with two model molecules: N-methylacetamide (NMA) and dimethyl sulfoxide (DMSO) and two osmolytes: glycine betaine (TMG)and urea....
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The hydration of selected biologically relevant molecules – the temperature effect on apparent molar volume and compression
PublicationThe densities and sound velocities at T = (288.15, 293.15, 298.15, 303.15 and 308.15) K were measured for aqueous solutions of glycine, trimethylamine-N-oxide, taurine and N-methylacetamide. From these data, the apparent molar volumes, V the apparent molar isentropic compressions, KS,, and the Passynski hydration numbers of solutes were determined. The concentration dependencies of the calculated quantities, their limiting values...
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Electron-impact ionization cross section calculations for 5-chloropyridine and 5-bromopyridine molecules
PublicationThe 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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Electron scattering cross sections for 1-pentene, H2C=CH-(CH2)2CH3, molecules
PublicationCross sections, both experimental and theoretical, are reported for electron scattering from 1-pentene (C5H10) molecules. Absolute grand-total cross sections (TCSs) were measured at electron impact energies ranging from 1 to 300 eV, using a linear electron-transmission technique. The dominant behaviour of the experimental TCS energy function is a distinct asymmetric enhancement with the maximum located around 6.5 eV. Discernible...
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Electron scattering from 2-methyl–1,3-butadiene,C5H8, molecules: Role of methylation
PublicationWe report cross-section results from experimental and theoretical investigations into electron collisions with the 2-methyl–1,3-butadiene [C5H8] molecule. The current results are compared with our previous results for the 1,3-butadiene [C4H6] molecule, a structural homologue of 2-methyl–1,3-butadiene, to investigate how the methylation (the substitution of hydrogen atom by a methyl group) affects the shape and/or magnitude of the...
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Sample Concentration of Charged Small Molecules and Peptides in Capillary Electrophoresis by Micelle to Cyclodextrin Stacking
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PELP1 and SRC kinase as important molecules in the estrogen-mediated pathway in human testis and epididymis
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Diffusive properties of solvent molecules in the neighborhood of a polymer chain as seen by Monte-Carlo simulations
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Luminescent collisions of He+ and He++ ions with H2 molecules at energies below 2 keV
PublicationSpectroscopic studies of collisions between He+ and He++ ions with H2 gas target have been performed in the 200–600nm wavelength range. Atomic lines of hydrogen Balmer series and several helium lines were identified and their excitation functions between 50 eV and 1keV (2keV for He++) were determined.
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UV-visible emision as a probe of core excitations applied to the furan carbon dioxide molecules
PublicationWykonano badania wzbudzenia wewnątrz powłokowego drobin furanu i dwutlenku węgla korzystając ze spektroskopii fluorescencyjnej w zakresie widzialnym i UV. Przeprowadzono pomiary emisji linii Hα i Hβ w pobliżu progu wzbudzenia O 1s i C 1s drobin furanu i dwutlenku węgla
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Electron scattering by planar boron-containing molecules BX3(X=F, Cl, CD3)
PublicationPraca prezentuje absolutny całkowity przekrój na rozpraszanie elektronów dla drobiny B(CD3)3 w zakresie niskich i średnich energii, otrzymany liniową metodą transmisyjną. Porównanie wyników dla innych płaskich drobin zawierających bor jako atom centralny - BX3(X=F, Cl) ukazuje rolę atomów zewnętrznych w procesie rozpraszania.
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Organic electroluminescent devices containing phosphorescent molecules in molecularly doped hole transporting layer.
PublicationW pracy opisano mechanizm świecenia diody dwuwarstwowej diody elektroluminescencyjnej (EL) o zewnętrznej kwantowej wydajności świecenia osiągającej 9% fot./elektron. Warstwę transportującą elektrony tworzyła pochodna osadiazolu (PBD) otrzymana metodąnaparowania próżniowego. Warstwę transportującą dziury uzyskano przez wylanie roztworu poliwęglanu(PC), dendrymeru aminowego m-MTDATAoraz fosforyzującego kompleksu irydu Ir(ppy)3 i...
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Triplet energy exchange between fluorescent and phosphorescent organic molecules in a solid state matrix.
PublicationW pracy przedstawiono model wymiany energii trypletów na podstawie mechanizmu Dextera i zweryfikowano go w układzie dwuamina TPD : organiczny komleks Ir(ppy)3: matryca poliwęglanowa, mierząc czasy życia emisji Ir(ppy)3 przy różnych koncentracjach molekuł TPD.
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Role of methylation in electron scattering on X(CH3)4 (X = C, Si, Ge) molecules
PublicationTotal 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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Characterization of Bioactivity of Selective Molecules in Fruit Wines by FTIR and NMR Spectroscopies, Fluorescence and Docking Calculations
PublicationFourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies were applied to characterize and compare the chemical shifts in the polyphenols’ regions of some fruit wines. The obtained results showed that FTIR spectra (1800–900 cm−1) and 1H NMR (δ 6.5–9.3 ppm) of different fruit wines can be used as main indices of the year of vintage and quality of fruit wines. In addition to the classical determination...
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Hydrogen migration in formation of NH(A3Π) radicals via superexcited states in photodissociation of isoxazole molecules
PublicationFormation of the excited NH(A 3Π) free radicals in the photodissociation of isoxazole (C3H3NO) molecules has been studied over the 14-22 eV energy range using photon-induced fluorescence spectroscopy. The NH(A 3Π) is produced through excitation of the isoxazole molecules into higher-lying superexcited states. Observation of the NH radical, which is not a structural unit of the isoxazole molecule, corroborates the hydrogen atom...
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Total cross section for low-energy electron scattering from formic acid, (HCOOH), molecules
PublicationTotal cross section (TCS) for low-energy electron scattering from formic acid molecules has been measured using electrostatic electron spectrometer working in linear transmission mode. Two local maxima centered around 1.7 eV and 7.8 eV have been observed and associated with resonant scattering processes.
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Interplay between Aryl···Perfluoroaryl and Hydrogen Bonding Interactions in Cocrystals of Pentafluorophenol with Molecules of Trigonal Symmetry
PublicationCocrystals of seven star-shaped triaryl compounds with pentafluorophenol (pfp) were prepared and structurally characterized by the single-crystal X-ray diffraction method. Cocrystallization of pfp with planar (or almost planar) compounds gave six 3:1 molecular complexes with well-defined layered structures. The layers are composed of alternating pfp3 trimers, linked by hydrogen bonding, and triaryl molecules held together in planes...
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Hydrogen migration observed in fragmentation of the pyridine molecules in collisions with the H+, H2+, He+and He++cations
PublicationThe hydrogen atom migration preceding fragmentation of the pyridine molecules by the H+, H2+, He+ and He++ collisions has been investigated in the 5-2000 eV energy range. The pyridine molecule structure is lacking of the NH group, thus formation of the NH radicals is an evidence of the H atom relocation prior to the cation-induced fragmentation. The NH(A3Π) fragmentation yields measured by detecting its A3Π→X3Σ− fluorescence show...
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Electron Scattering on X(CH3)4 Molecules: Applicability of Simple Additivity Rule and Role of Methylation
PublicationTo investigate influence of target methylation (substitution of a hydrogen atom by methyl group) on electron-collision processes we compare absolute total cross sections for XH4 and X(CH3)4 molecules, where X is Si and Ge, respectively. We also compare experimental TCSs energy dependencies with estimated data obtained using simple formula and TCSs for methyl group and those for SiH4 and GeH4. Electron-scattering TCSs for mentioned...
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Formation of OH Radicals as Evidence of Intramolecular Hydrogen Migration in Cation-Induced Dissociation of Furan Molecules
PublicationWe present the experimental results on a hydrogen atom migration preceding fragmentation of the furan molecules induced by the H3+ and C+ impact. The excited OH(A2Σ+) radical has been detected among the furan decomposition products using collision-induced emission spectroscopy. However, the OH moiety is absent in the furan ring skeleton, so detecting the OH(A2Σ+→X2Π) luminescence indicates the intramolecular H atom relocation prior...
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Photofragmentation of tetrahydrofuran molecules in the vacuum-ultraviolet region via superexcited states studied by fluorescence spectroscopy
PublicationPhotofragmentation of tetrahydrofuran molecules in the vacuum-ultraviolet region, producing excited atomic and molecular fragments, has been studied over the energy range 14-68 eV using photon-induced fluorescence spectroscopy. Excited hydrogen atoms H(n), n = 3-11, have been detected by observation of the Hα to Hı lines of the Balmer series. The diatomic CH(A2Δ), CH(B2Σ-) and C2(d3Πg) fragments, which are excited to low vibrational...