bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dichroic Spectra of Anthracene, Acridine and Phenazine in Stretched PVA sheets
Authors: Inoue Hiroyasu , Hoshi Toshihiko , Masamoto Tadashi , Shiraishi Junko , Tanizaki Yoshie 
Published: March 2014

AbstractDichroic spectra of anthracene, acridine and phenazine in stretched PVA (polyvinylalcohol) sheets were measured above 210 mμ. Using the results of the dichroic spectra, the absorption spectrum of each compound was divided into two kinds of absorptions polarized to the long (x) and the short (y) axes of the molecule. By comparing the results of the divided spectra with those of the Pariser‐Parr‐Pople calculations involved a variable ß approximation, assignment of the absorption bands for the above compounds were established. Near ultraviolet absorption spectrum of each compound consists of four bands, which are polarized to the y‐, x‐, x‐ and y‐axes of the molecule in the order of decreasing wavelength.
Rates of Hydrated Electron Reactions with Undissociated Carboxylic Acids
Authors: Mićić O. , Marković V. 
Published: March 2014

AbstractThe rate constants for the reaction series RCOOH + eaq−, with different substituents R(H, CH3, C2H5, CHO, CH2OH, CH3CHOH, C6H5, CH2COOH, (CH2)2 · COOH, CH2COO−) have been determined by the steady state competition kinetics. The competing reaction was the reaction of hydrated electrons with hydronium ions. The effect of the substituents on the rate constants was shown to be mainly of inductive type. The reaction rates can be correlated by means of Taft's equation with the positive slope ρ* = 1.94 ± 0.15. As expected, significant deviations are observed in the cases in which other interactions besides inductive are possible. H atoms are not formed in these reactions. In the case of formic acid, acetic acid and propionic acid reactions proceed in two paths at comparable rates. H atoms are formed as a product in one of them.
Kinetics and Mechanism of the Radiolysis of some Tris‐oxalto Complexes in Aqueous solutions
Authors: Murgulescu I. G. , Paun J. 
Published: March 2014

AbstractThe radiolysis of some tris‐oxalatocomplexes of transition metals has been studied in neutral aqueous solutions. As radiation sources have been used α‐Po210, β‐Sr90, and γ‐Co60.In order to establish the reaction mechanism the influence of the following factors has been investigated: radiation dose, does rate. L.E.T., solute concentration, the presence of some scavangers for reducing and oxidizing species and the presence of oxygen.The predominant process in the radiolysis of these compounds is the reduction of the complex ions by the hydrated electrons and hydrogen atoms:

The nature of the final radiolysis products as well as the kinetics of their formation during irradiation is different for each complex ion.
Pulse Radiolysis of Metal‐Organic Compounds. I. Aluminiumalkyl‐naphthalene‐diethylether‐system
Authors: Lehmkuhl H. , Getoff N. , Schwörer F. 
Published: March 2014

AbstractAn attempt was made to simulate metal‐organic reactions of the triethylaluminium‐naphthalene‐diethylether‐system by pulse radiolysis. Using 1 μs‐pulses a partial absorption spectrum of esol− in ether in the range from 800 to 1200 nm was obtained at room temperature. The radicals and radical‐ions, produced by the pulse radiolysis of argon saturated ether, possess a total absorption spectrum in the range from 210 to 350 nm. The transient absorption decays with mixed order.The intermediates, obtained in argon‐saturated ether solutions of triethylaluminium (10−3 – 10−2 M) have a total absorption spectrum between 220 and 340 nm which changes considerably 50 μs after pulse end. Here too, mixed kinetics are occuring (at 250 nm. k1 ∼ 6 · 104 s−1 and k2/ε ≈︁ 107 cm · s−1). By saturating pure ether with HCl gas the solvated electrons are scavenged. Similar results as in the presence of argon were obtained, showing that the reactivity of H‐atoms is rather high too.A total absorption spectrum of C10H8− and C10H9 species was measured by irradiating naphthalene (10−3 – 10−2 M, argon saturated) in ether. Using again HCl gas as a scavenger for esol− the spectrum of C10H9 radicals was obtained with maxima at 300, 307 and 320 nm. It changes strongly 50 and 100 μs after the pulse, indicating that these species are very reactive, probably with HCl. They disappear in a second order reaction (at 330 nm k2/ε = 2.8 · 106 cm ≈︁ s−1). Subtracting the spectrum of C10H9 from the total one, the absorption spectrum of C10H8− with maxima at 330 and 370 nm was obtained. Its shape does not change very much with time, suggesting that the second order disappearance of the radical‐anions (at 370 nm k2/ε = 5 · 107 cm · s−1) is mainly due to a dimerisation process.Investigating the total absorption spectrum of the complete triethylaluminium‐naphthalene‐diethylether‐system (saturated with argon) at different times after the pulse, the appearance of a new maximum at 312 nm was observed. It was attributed to the intermediate, formed by the reaction of Al(C2H5)2+ and C10H8− and/or C10H9 species. This assumption was supported by analysing the final radiolytic products of the system.A full report of the absorption spectra, kinetic data and product analysis will be published elsewhere.
Transient Species in the Pulse Radiolysis of Periodate Ion in Neutral Aqueous solution
Authors: Barat F. , Gilles L. , Hickel B. , Lesigne B. 
Published: March 2014

AbstractTwo transients are observed with light absorption between 300 nm and 600 nm in the pulse radiolysis of neutral aqueous solution with dissolved periodate ions: The influence of scavengers and the study of the salt effect have permitted their identification as the IO4 radical and the IO42‐ ion with the extinction coefficients ε520nm(IO4) ∼ 3000 M‐1 cm‐1 and ε360nm(IO42‐) ∼ 1000 M−1 cm−1 respectively.The disappearance of these species are second order processes with the rate constants 2k = 9 · 108 M−1 s−1 for IO4 radicals and 2k = 2.5 · 1010 M−1 s−1 for IO42‐ ions.The rate constant of the reaction IO4− + OH → IO4 + OH− has been determined as k = (4.5 · 0.5) 108 M−1 s−1 by following the formation of IO4.
Concerning the Optical Absorption Band of the Hydrated Electron
Authors: Kenney‐Wallace Geraldine , Walker David C. 
Published: March 2014

AbstractPhotobleaching of hydrated electrons in liquid water has been attempted under the immense light flux of a Q‐switched ruby laser. The 20 nanosecond ruby pulse was utilized as both the exciting light and a monitor for the absorbance of eaq−. Whereas stable solutions of organic dyes (cryptocyanine and methylene blue) showed marked nonlinear absorption due to saturation of optical transitions, no such change was observed for hydrated electrons even though the light intensity was varied by >107 up to 200 photons per hydrated electron per cm2. Consequently the photoexcited state lifetime is estimated to be less than 6 · 10−12 sec. This finding is discussed briefly in terms of three possible origins for the absorption band, namely that involving excitation to a bound excited state, as a photoionization efficiency profile or as a distribution of potential wells of various depths.
Isothermal Compressibilities of Sodium‐ and Potassium‐Ammonia solutions
Authors: W. Böddeker K. , Vogelsgesang R. 
Published: March 2014

AbstractThe isothermal compressibility of alkali metal‐ammonia solutions, measured at several pressure intervals up to 1000 at, is compared with the adiabatic compressibility and is used to calculate the apparent molar volume of the dissolved metal at various pressures.
Radiolytic Formation of Ammoniated Electrons of Long Lifetime at Room Temperature
Authors: Belloni J. , Fradin De La Renaudière J. 
Published: March 2014

AbstractThe yields of the γ radiolysis of liquid ammonia at various pH are compared. In basic solutions, containing an alkali amide, the attack of hydrazine by H atoms is less important, since these species are transformed into ammoniated electrons which do not destroy N2H4. On the other hand, adding hydrogen to amide solutions increases the initial yield G(N2H4), so suggesting that the NH2 radicals may be scavenged by H2 and also transformed into eam−. Under those conditions the disappearance reactions of eam− are all hindered.Effectively, after irradiation, for an H2 pressure of 0.2 – 0.8 atm (5 ± 10−2 M KNH2) an absorption in near infra‐red with the same characteristics as for eam− is observed. This absorption increases first linearly with the dosis and the initial yield G(eam−) is independent of H2 pressure above 0.6 atm. After the end of irradiation, the decrease of absorption with time is of the first order and very slow (1/2 ± 2 hr) as in the spontaneous decomposition of alkali metal solutions.
Theoretical Studies of Excess Electron States in Liquids
Authors: Jortner Joshua 
Published: March 2014

AbstractIn this paper an attempt will be made to review the current state of the art in our understanding of excess electron states in non polar and polar liquids, with an emphasis on the following problems:

The nature of quasi free and localized excess electron states.
Localization criteria.
Energetic stability of the localized excess electron state.
Nature of electron solvent interactions.
Configurational charges in the medium.
A brief survey of excess electron states in non polar solvents such as He, Ar, Kr, Xe, H2, and D2 will focus attention on the general stability problem of an excess electron in a non polar dense fluid, configurational diagrams in ground and excited states, optical properties and non radiative relaxation processes. The basic problems involved are identical with those encountered in the study of excess electron states in polar solvents.Excess electron states in polar solvents will be handled by the application of continuum and molecular models. Information will be presented concerning the quasi free excess electron state in polar solvents, the electronic and medium rearrangement energy for the cavity model, the configurational stability of ground and excited state, configurational diagrams, optical properties, optical lineshapes and relaxation phenomena.
Halogen‐Austausch‐Reaktionen in Molekularstrahlen
Authors: Loesch H. J. , Beck D. 
Published: March 2014

AbstractFür die exothermen Halogenaustausch‐Reaktionen Cl + Br2, J2, BrJ (beide Kanäle) und Br + J2 wurden Winkelverteilungen der molekularen Reaktionsprodukte gemessen. Für Cl + J2 wurde bei den Labor‐Winkeln θ = 10°, 30° und 60° auch die Produktgeschwindigkeitsverteilung bestimmt. Die Analyse dieser Daten zeigt: a) beträchtliche Bruchteile direkter, im Massenmittelpunktsystem nach vorn streuender Prozesse bei Cl + Br2, J2 und BrJ (→ ClBr + J), erhöhte Rückwärtsintensität bei Br + J2 und nahezu vorwärts‐rückwärts symmetrische Streuung bei Cl + JBr → ClJ + Br, was auf eine Verschiedenheit der Reaktionszeit bei diesen Systemen hindeutet; b) eine Bevorzugung der inneren Freiheitsgrade im Energiehaushalt aller Reaktionen; c) Aktivierungsenergien Ea ⩽ 1 kcal/mol für die direkten Reaktionen; d) integrale Reaktionsquerschnitte beträchtlich kleiner als die gaskinetischen, wodurch eine starke sterische Behinderung der Reaktionen nahegelegt ist. Diese Resultate werden mit BEBO‐Potentialen verglichen. Es wird darauf hingewiesen, daß neben der Feinstruktur der Potentialflächen bei 3‐Halogen‐Atom‐Systemen eine zusätzliche Entartung wahrscheinlich ist.
Die ESR‐Spektren der Elemente der 6. Hauptgruppe in der Gasphase
Authors: Tiedemann P. , Mihelcic D. , Schindler R. N. 
Published: March 2014

AbstractIn einer kinetischen Untersuchung der Reaktion von atomarem Wasserstoff mit H2Se und H2Te wurden die ESR‐Spektren von atomarem Selen und Tellur beobachtet. Die Spektren werden beschrieben und mit bekannten Aufnahmen von atomarem Sauerstoff und Schwefel verglichen. Die folgenden g'‐Werte für die Zustände 3P2 und 3P1 wurden ermittelt:

Die Isotope Selen 77, Tellur 123 und 125, deren Kernspin I = 1/2 ist, zeigen eine deutliche Aufspaltung der magnetischen Niveaus in zwei Gruppen. Die Zuordnung der einzelnen Linien ergibt sich aus der Berechnung des Aufspaltungsbildes. Die folgenden Hyperfeinkopplungskonstanten wurden erhalten:

.
Untersuchung schneller Reaktionen nach Mikrowellenentladungen 2. Bestimmung von stabilen und kurzlebigen Produkten nach Entladung in einem Methan‐, Ammoniak‐ und Ammoniak‐Methan‐Helium‐Gemisch
Authors: Herbrechtsmeier P. , Gg. Wagner H. 
Published: March 2014

AbstractMethan und Ammoniak sowie ein Gemisch beider Gase wurden in einem Strömungssystem einer elektrodenlosen Mikrowellenentladung unterworfen. Die Zwischen‐ und Endprodukte konnten mit Hilfe eines Molekularstrahlabsaugsystems massenspektrometrisch analysiert werden. Eine Abschätzung der Radikalkonzentrationen von CH3, CH2 und CH führte zu der Reihenfolge CH2 > CH3 > CH. Die Bildung von Cyanwasserstoff nach der Entladung in einer Ammoniak‐Methan‐Mischung wurde mit der Reaktion gedeutet:

Ferner konnten als Reaktionsprodukte Methylamin und Methylenimin analysiert werden.
A Comparative Study of Quasielastic Neutron Scattering and NMR Relaxation in Liquid Acetonitrile
Authors: Zeidler M. D. 
Published: March 2014

AbstractNeutron scattering experiments were performed on liquid acetonitrile in the temperature range ‐19°C to 75°C. The quasielastic peak was Fourier‐transformed to obtain the intermediate scattering law.The experimental results are compared to theoretical scattering laws calculated on the basis of the random walk theory. Expressions for the rotational and translational contributions are derived. Their correspondence with equivalent expressions for the nuclear magnetic relaxation rates is discussed in detail. The parameters in the theoretical intermediate scattering laws are taken from published NMR relaxation data. Translational self‐diffusion constants were determined by spin‐echo experiments. Different results from both types of experiments are discussed.
Reduction of Silver Bromide with Hydroquinone — Studies on the Local Cell Mechanism —
Authors: Sasaki Kazuo , Kurimoto Haruyuki , Shiba Haruo 
Published: March 2014

AbstractThe local cell mechanism proposed by Jaenicke and Sutter for the reduction of silver bromide with aqueous hydroquinone has been studied. Main purpose was to determine the relative contribution of the rate of reaction through the local cell mechanism to the whole rate. Two series of experiments were carried out, i.e. 1. measurement of maximum out‐put current of a galvanic cell having a form of magnified image and 2. measurement of ordinary chemical reaction rate of silver bromide with aqueous hydroquinone. The rates determined from these two experiments were compared to obtain the following findings.
The reaction rate was limited by diffusion of hydroquinone in aqueous phase. As a consequence, when the chemical process was measured in a stationary solution, the rate obtained from the galvanic cell always exceeded the one obtained from the chemical process.
When, however, the chemical process was carried out in a stirred solution (a platinum wire carrying silver bromide on its surface was rotated actually), the rate converged to the one determined from the galvanic cell experiment.
The effects of the presence of bromide anion in the solution and the replacement of reducing agent from hydroquinone to hydroquinone monosulfonate were also studied. The results were entirely consistent with that described above. Accordingly, it can be concluded that the reduction of electrolytically prepared silver bromide with aqueous hydroquinone proceeds almost exclusively through the local cell mechanism.
Über den Reaktionsablauf in Fluor‐Flammen. II. Konzentrationsprofile in Flammen der Systeme: H2–F2, H2–F2–NH3, NH3–F2, C2H2–F2 und C2H4–F2
Authors: Homann K. H. , Maclean D. I. 
Published: March 2014

AbstractDer Verlauf der Konzentrationen von Ausgangsstoffen, stabilen Reaktionsprodukten und aktiven Zwischenprodukten wurde in Niederdruckflammen der obengenannten Systeme auf einem Vielfach‐Diffusionsbrenner gemessen. H2–F2: Vorläufige Messungen der H2‐ und F‐Atom‐Profile ergeben gute übereinstimmung mit den Ergebnissen von getrennten Messungen der Reaktion F + H2 ± HF + H. H2–F2–NH3: Ammoniak übt eine inhibierende Wirkung auf die H2–F2‐Flamme aus, die auf die Bildung von festem NH4F zurückgeführt wird. C2H2–F2: Hauptprodukte dieser Flamme sind HF und CF2, das bei Abkühlung zu C2F4 rekombiniert. Die Natur der Zwischenprodukte deutet darauf hin, daß Anlagerungsreaktionen von F bzw. F2 an ungesättigte Kohlenwasserstoffe bzw. deren Radikale eine Rolle spielen. Die Rußbildung in dieser Flamme wird mit der einer C2H2–O2‐Flamme verglichen. C2H4–F2: Da C2H4 in der Flamme zu einem großen Teil zunächst zu C2H2 abgebaut wird, ähnelt diese Flamme sehr der C2H2–F2‐Flamme.
Lumineszenz‐ und Schwingungsspektren kristallisierter Chrom(III)‐Dimethylsulfoxid‐Verbindungen
Authors: Koglin E. , Krasser W. 
Published: March 2014

AbstractDie Lumineszenzspektren der polykristallinen Verbindungen [Cr(DMSO)6]J3 und [Cr(DMSO)6](CIO4)3 (DMSO = Dimethylsulfoxid) werden bei 77 °K und 4,2 °K aufgenommen.In der Perchlorat‐Verbindung wird bei 77°K ein starker Fluoreszenzübergang beobachtet. Die Jodid‐Verbindung zeigt nur den Phosphoreszenzübergang. Da das Lumineszenzspektrum die Schwingungsstruktur des 4 A2g‐Grundzustandes widerspiegelt, sind die Raman‐, IR‐ und FIR‐Spektren aufgenommen worden.Der kurzwelligste Übergang der Fluoreszenz liegt bei der Perchlorat‐Verbindung in der Nähe des Phosphoreszenzüberganges und überlagert dessen Schwingungsbanden.Bei der Jodid‐Verbindung wird der Phosphoreszenzübergang mit seinen Schwingungsbegleitbanden nicht beeinflußt und die im Raman. IR und FIR gemessenen und zugeordneten Schwingungen spiegeln sich gut im Lumineszenzspektrum wider.
Mass Spectrometric Investigations of Silver Halides I: Mass Spectrum, Appearance Potentials, and Fragmentation Scheme of Silver Chloride
Authors: Gräber P. , Weil K. G. 
Published: March 2014

AbstractDuring electron impact ionisation of Silver chloride vapor the following ionic species are formed (appearance potentials in brackets): Ag2+, Ag+ (11.1 eV), AgCl+ (10.8 eV), Ag2+ (18 eV), Ag2Cl+ (10.8 eV), Ag+, 3Ag3Cl+, Ag3Cl+2 (11.1 eV), Ag3Cl3+ (10.4 eV). From the ionisation efficiency curves, appearance potentials, and the dependence of relative intensities on electron energy, it is concluded that the vapor consists of AgCl and Ag3Cl3 molecules. The presence of a very small fraction of Ag2Cl2 molecules can not be excluded. For the dissociation energy of AgCl we get 3.5 eV, for that of AgCl+ 0.3 eV. A complete fragmentation scheme for the ions is evaluated and discussed.
Untersuchungen von Ionenreaktionen mittels Photoionisations‐Massenspektrometrie VI. Reaktionen in Acetylen, Äthylen, Methan und deren Gemischen
Authors: Warneck Peter 
Published: March 2014

AbstractProduktverteilungen und Geschwindigkeitskoeffizienten für die bei der Photoionisation von Acetylen, Äthylen und Methan primär auftretenden Ionenreaktionen wurden bei geringen Reaktionsenergien (0,16 eV) gemessen. Durch Verwendung der Ionisierungswellenlängen 1087 und 923 Å, bei Acetylen auch 765 Å, wurde die Fragmentierung der Primärionen weitgehend unterdrückt, so daβ überwiegend eine eindeutige Zuordnung der Reaktionswege möglich war. Für die Reaktionen der Mutterionen in Acetylen und Äthylen ergaben sich bei kürzeren Wellenlängen Änderungen der Produktverteilungen, die durch elektronisch angeregte Ionen hervorgerufen werden. Für Äthylen wird außerdem eine Verringerung des Geschwindigkeitskoeffizienten beobachtet. Das termolekulare Assoziationsprodukt C4H+8 entsteht ebenfalls mit geringerer Ausbeute. Für das entsprechende Assoziationsprodukt in Acetylen, C4H+8, wurde ein bimolekularer Bildungsmechanismus beobachtet, wahrscheinlich aufgrund intramolekularer Schwingungsrelaxation. Bei der Reaktion von C2H2+ mit Äthylen konnte Umladung nicht nachgewiesen werden, im Gegensatz zu früheren Versuchen mit Elektronenstoß. Dagegen war Umladung bei den Reaktionen von Methanionen mit Acetylen und Äthylen von Bedeutung. Die Ergebnisse werden mit den früher mittels Ionisation durch Elektronenstoß erhaltenen Daten verglichen und diskutiert.
On the Kinetics of the Formation of Berylliumfluoride Complexes
Authors: Knoche W. , Taraszewska J. 
Published: March 2014

AbstractThe kinetics of the disproportionation 2BeF2 ⇌ BeF+ + BeF‐3 has been studied with the pressure‐jump relaxation technique. In acid solutions (pH < 3.5), a parallel reaction path has been found where HF appears as an intermediate. In more basic solutions (pH > 4.5), another parallel reaction could be identified where a trinuclear intermediate exists. For the pH‐independent reaction path the rate constant (k = 16sec‐1 M‐1 ), the energy of activation (EA = 14 kcal mol‐1 ), and the volume of reaction (ΔV= 2.4 cm3 mol‐1 ) have been determined.
Messung der physikalischen Adsorption von Xenon an Quarzglas
Authors: Ahrens‐Botzong Rudolf , Hess Peter , Schäfer Klaus 
Published: March 2014

AbstractDie Adsorptionsisothermen von Xenon an Quarzglas wurden bei den Temperaturen 77,3 K, 77,4 K, 80,0 K und 90,0 K im Druckbereich von 10‐6 bis 10‐2 Torr gemessen. Die BET‐Methode ergab eine etwas gröβere Oberfläche als die Methode nach Dubinin‐Radushkevich. (Rauhigkeitsfaktor nach BET: 2,6; nach DR: 1,5.) Die isostere Adsorptionswärme steigt unterhalb der Monobedeckung fast linear an. Dies deutet darauf hin, daβ es sich bei Quarzglas ähnlich wie bei Duranglas trotz der geringen Oberflächenrauhigkeit um eine heterogene Oberfläche handelt.
Excess Volumes of a Binary Liquid Mixture at High Pressure
Authors: Engels P. , Schneider G. M. 
Published: March 2014

AbstractThe excess volume of the system water‐3‐methylpyridine has been determined by direct measurements at 50, 81.5, and 95°C up to 2500 bar. The apparatus is described.The results are used to calculate the variation of the molar excess Gibbs energy GE with pressure. The variation of the molar excess enthalpy HE and the molar excess entropy SE with pressure are discussed qualitatively.The second derivative of the excess volume with respect to the molefraction is compared with thermodynamic conclusions derived from liquid‐liquid immiscibility phenomena.
The MoSe2 Electrochemical Solar Cell: Anodic Coupling of Electron Transfer to d → d Photo‐Transitions in Layer Crystals
Authors: Tributsch Helmut 
Published: March 2014

Abstractn‐type MoSe2 layer crystals were successfully used as photoelectrodes in electrochemical solar cells. Their mechanism is based on d → d phototransitions in the electrode in combination with anodic electron transfer from suitable redox couples in the adjoining electrolyte (Fe2+/3+, I−/I2). Redox agents with potentials more negative than that of water can be oxidized by holes from the low lying Mo 4d energy band clearly before the anodic onset of the photoreaction with water molecules which would lead to the formation of selenic acid and to a gradual photodissolution of the electrode. In this way it is possible to operate regenerative electrochemical solar cells by‐passing corrosive anodic reactions. With MoSe2: I−/I2 solar cells photocurrent densities of 22 mA/cm2, photovoltages of 0.55 V and energy conversion efficiencies between 4 and 5% were obtained in the red and near infrared spectral region. Their stability behaviour was tested at photocurrent densities between 11 and 12 mA/cm2 over a period of more than 1200 hours (50 days). No deterioration of the photoelement was observed. Capacity measurements indicate that reducing agents such as iodide ions are chemisorbed to surface states formed by trapped holes on d‐orbitals. The resulting surface charge redistribution causes a relative shift of energy levels which suppresses the reaction with water and induces a space charge polarization that facilitates photoactivated electron transport from iodide.