bluuebunny/crossref_metadata_2025 huggingface dataset:
The structure of water in human ras oncogene proteins
Authors: Yu Jeong Yun , Shin Jae Kwang , Jhon Mu Shik
Published: January 2005

High‐directional Monte Carlo (HDMC) simulations are performed to investigate the behavior of water molecules in the catalytic sites of human ras p21 proteins and the results are compared among three types of hydrated ras p21 proteins: the normal ras complexed with GDP (normal‐p21/GDP), the mutant ras complexed with GDP (mutant‐p21/GDP), and the normal ras complexed with GTP (normal‐p21/GTP). Also, the original Metropolis Monte Carlo (MMC) simulation is performed on the normal‐p21/GDP system. Comparison between HDMC and MMC shows the improved efficeincy of HDMC on this complicated system. Interaction between water molecules is represented by the TIP3P potential function. The solute–water interaction is represented by the Coulomb and van der Waals interactions from the CHARMM force field spliced with TIP3P. The mean‐square displacements and dipole correlation functions are reported. We specifically examined the hydrogen‐bond interactions existing near the catalytic sites, by the distribution of small water clusters connected by the hydrogen bond and by the average lengths and fluctations of hydrogen bonds between water molecules and solute atoms. Water molecules form different local structures in different types of the p21/GDP(GTP) complexes. The structure and motion of water molecules near the catalytic sites of the proteins are discussed in detail. © 1994 John Wiley & Sons, Inc.
Semisimilarity of molecular bodies: Scaling–nesting similarity measures
Authors: Mezey Paul G.
Published: January 2005

A simple, new technique for the evaluation of the similarity of molecular shapes is presented. The concept of semisimilarity (asymmetric similarity) is applied within the topological–geometrical framework of scaling–nesting similarity measures of molecules. The practical application of these similarity measures is illustrated by the examples of the three‐dimensional formal bodies of electronic charge densities of a set of simple molecules. © 1994 John Wiley & Sons, Inc.
Electron crystallization in two dimensions
Authors: Iyakutti K. , Palanichamy R. Rajeswara
Published: January 2005

The ground state of the 2D electron crystal is investigated using a localized representation for the electrons. Assuming a neutralizing background, calculation for a nonmagnetic electron crystal is performed. The areal electron densities corresponding to the crystallization for different rs values are computed and these are compared with the available experimental areal densities. An upper limit for the obtainable areal density has been predicted from our results. © 1994 John Wiley & Sons, Inc.
Alternating charge densities, peierls distortion, and charge‐conjugation symmetry in correlated one‐dimensional diatomic systems
Authors: Kuprievich Victor A.
Published: January 2005

The full‐optimized‐APSG approach based on the MC SCF technique is developed and applied to study ground‐state properties of one‐dimensional correlated systems. The effects of electron–electron interactions and bond relaxation are considered for the conjugated diatomic polymer; charge distribution and bond relaxation are calculated for the N = 50 chain within a wide range of site energy and e–e integral modulation involving the case of alternancy symmetry for diatomic systems. With relation to the results obtained, the problem of the neutral–ionic transition in mixed‐stack crystals is discussed. © 1994 John Wiley & Sons, Inc.
On the stability of the autodissociative ground electronic state of BeH2+
Authors: Chrysos Michael , Alikhani M. Esmail , Jacon Marcel
Published: January 2005

It is shown that the mechanism of spontaneous infrared emission enhances substantially the stability of the long‐lived ground electronic state of the exotic BeH2+, whose autodissociation becomes possible only via tunneling. The system, initially situated in any vibrational level (except the high‐lying ones for which dissociation is predominate) and statistically distributed over all rotational states, reaches stability through a cascade of dipole emissions toward lower levels. The rapid spatial variation of the dipole moment results in fast radiative processes and might suggest experimental observations easier to perform. The methodology is based on a recently presented analytic discrete variable representation (DVR) [D.T. Colbert and W.H. Miller, J. Chem. Phys. 96, 1982 (1992)] that facilitates calculations. This might prove particularly useful to spectroscopists, allowing a check of the quality of potentials produced by inversion methods or the reliable calculation of spectrochemical quantities. © 1995 John Wiley & Sons, Inc.
Extension of the Coulomb–Hole–Hartree–Fock theory to molecules
Authors: De Windt Laurent , Hofman Detlef W. M. , Pisani Lorenzo , Clementi Enrico
Published: January 2005

The Coulomb–Hole–Hartree–Fock method introduced by E. Clementi in the early 1960s and reparametrized more recently by S. Chakraworty and E. Clementi to compute the correlated electronic energy in atomic systems, is here extended to compute molecules. The new parametrization is obtained empirically by fitting first and second atomic ionization potentials from He to Ca and a few diatomic molecules. The present formulation makes use of either one or more determinants in order to ensure proper dissociation products, following the early proposal of G.C. Lie and E. Clementi in the context of density functional computations for molecular systems. The new formulation is tested against the dissociation energies of a large number of molecules and it is found satisfactory. © 1995 John Wiley & Sons, Inc.
A discrete look at localization
Authors: Hall G. G. , Rees D.
Published: January 2005

This article introduces a set of localized orthonormal functions to serve as basis functions for quantum calculations. They are defined to be eigenfunctions of the position operator in a function space. Their properties, including their variances, for a one‐dimensional system are developed. The application to simple harmonic motion is considered as an example and, in particular, the time evolution of an initially localized function is calculated and shown to be periodic. The theory can be interpreted as producing a discrete quantization of space with Hamiltonian interactions that are predominantly between nearest neighbors. These functions can also be used in approximate calculations. To illustrate their accuracy, the example of a Morse oscillator treated as a perturbation of a harmonic oscillator is reconsidered. It is shown that the localized functions in a variational calculation lead to a result that is a good approximation for the lowest states. Furthermore, the use of a wave function that is defined only at discrete points can be justified as the first approximation to this, so that its accuracy can also be discussed. © 1995 John Wiley & Sons, Inc.
Accurate local density photoionization cross sections by LCAO Stieltjes imaging approach
Authors: Stener M. , Lisini A. , Decleva P.
Published: January 2005

Photoionization cross sections are evaluated at the local density level avoiding any potential shape approximation by employing the Stieltjes imaging (ST) technique in conjunction with large (STO) basis LCAO calculations. The ST technique proves accurate in comparison with full continuum calculation on the noble gases ionization. Several choices for the final‐state potentials, including different exchange‐correlation potentials, are tested on the noble gases, as well as in H2O and CO. Finally, several molecules are investigated employing the transition‐state xα potential and the results compared with available experimental data and previous calculations. The accuracy of the proposed approach appears quit comparable to the ab initio static‐exchange level, removing spurious resonances associated to the muffin‐tin approximation, and should prove useful in the analysis and interpretation of cross‐section data for large systems, where it is shown that basis‐set requirements become less stringent. The accuracy obtainable for the cross‐section profiles allows close comparison with experimental data, which, although showing good general agreement for the shape of the cross‐section profile, indicates the need of a further refinement of the theoretical model. © 1995 John Wiley & Sons, Inc.
Interpretation of the high‐energy band within the photoelectro spectra of alkanes both in terms of appropriate orbitals and on the basis of chemical structure
Authors: Gineityte V.
Published: January 2005

Two generalized interpretations of the high‐energy band (HEB) within the photoelectron spectras (PES) of alkanes, usually referred to as the C2s band, have been suggested. The quantum chemical one consists of attributing to the HEB of any alkane (CnH2n+2) the chain of n similiar orbitals ηk (k = 1…n), each of them containing mainly one 2sc AO and some contributions of another four orbitals from its nearest environment. The structure of each orbital ηk has been shown to be similar to that of the lowest totally symmetric MO of methane. The chemical interpretation of the same band involves relating it and the definite subspectrum of the full chemical graph of alkane, associated mainly with its C skeleton. The interrelation of these two complementary interpretations follows from the one‐to‐one correspondence between the orbitals ηk and the CH2(CH3) groups in alkane. © 1995 John Wiley & Sons, Inc.
Cubic‐grid Gaussian basis sets for electron scattering calculations. I. Definition and construction
Authors: Čársky Petr , Hrouda Vojtéch , Michl Josef
Published: January 2005

We propose a new type of Gaussian basis sets for use in calculations of electron scattering by molecules. Instead of locating the basis‐set functions on the atomic centers of the target molecule, we place primitive s‐type Gaussians at the positions of a cubic lattice with a regular grid. The grid and the Gaussian exponent are fixed so as to give the best representation of the plane‐wave function. Plane‐wave functions and Green functions obtained by means of the cubic‐grid basis set are tested graphically against exact functions and functions expressed by means of a conventional Gaussian basis set. © 1995 John Wiley & Sons, Inc.
Variational calculations for the hydrogen atom confined in spaces with paraboloidal and spheroidal boundaries
Authors: Cruz S. A. , Ley‐Koo E. , Marín J. L. , Taylor‐Armitage A.
Published: January 2005

Variational calculations for the lowest‐energy states of the hydrogen atom confined in (A) semi‐infinite spaces with paraboloidal boundaries, (B) symmetrical boxes with paraboloidal surfaces, and (C) prolate spheroidal boxes were performed with geometry‐adapted trial wave functions. Comparisons of variational energies with the exact energies available for the respective geometries provide indications on the reliability of the trial wave functions. This is a necessary and preliminary step to investigate atoms with several electrons in the corresponding confining geometries. © 1995 John Wiley & Sons, Inc.
On master equations, spectral resolutions, and self‐energy fields in propagator theories for quantum open systems
Authors: Bochicchio Roberto C. , Grinberg Horacio
Published: January 2005

Master equations for propagators in quantum open systems and their spectral resolutions are derived. The Zwanzig partitioning scheme along the superoperator algebra are used to derive equations of motion for partitioned operators in a Liouville space. The reservoir influence on the dynamical evolution of operators is shown to lead explicitly to dissipative effects arising from memory terms in the evolution equations of such operators. It is also shown that spectral representations may be written in a self‐consistent analytic way by means of the self‐energy fields for transition energies of the system by taking into account the lack of the complete knowledge about the reservoir. A kinematic fluid interpretation of the resultant equations is given and an explicit form of the “collision” superoperator is obtained. Finally, a simple example to illustrate the determination of self‐energy fields for the system–reservoir interaction corrections is given. © 1995 John Wiley & Sons, Inc.
A new boundary treatment: HF surface potential model applied to solid‐state cluster calculations
Authors: Liu Hong‐Lin , Chen Nian‐Yi , Ladik Janos J. , Otto P.
Published: January 2005

A new boundary treatment, a Hartree–Fock (HF) surface potential model, is proposed to deal with the surface effect in the solid‐state cluster calculations using the LCAO–MO–SCF ab initio method. The surface potential arises from one or more atoms, which have no basis function and are added to the calculated cluster system. These atoms are placed in such sites so that the HF potential field of the calculated system should possess a point‐group symmetry. The surface potential could be found by the corresponding HF potential using a symmetry operator. The fact that a rather symmetric electronic structure of the asymmetric cluster YBa2CuZn2O7 is obtained using the HF surface potential shows that the surface effect in the cluster calculations could be neutralized to a great extent. © 1995 John Wiley & Sons, Inc.
Accurate energy eigenvalues for enclosed hydrogen atom within spherical impenetrable boxes
Authors: Aquino A. Norberto
Published: January 2005

We study the hydrogen atom confined within spherical impenetrable walls. The potential in the box is the Coulombian potential and outside the box the potential is infinite. To compute the energy eigenvalues of the Schrödinger's equation, we use a method proposed few years ago by Campoy and Palma to solve free quantum systems. The energy eigenvalues are computed with great accuracy for different box sizes, in addition we also compute few position expectation values that are related with the hyperfine splitting, nuclear magnetic shielding, polarizability, and pressure. Our results are more accurate than the literature calculations. © 1995 John Wiley & Sons, Inc.
Direct solution of the many‐body Schrödinger equation in the hyperspherical formalism: Application of the CFHH–GLF method to a set of He‐like systems
Authors: Bian Wensheng , Deng Conghao
Published: January 2005

We apply the CFHH–GLF method, a modified version of our HH–GLF method, to directly solve the three‐body Schrödinger equation for a set of He‐like systems, including H−, He, Li+, Be2+, and B3+. Correlation functions with no adjustable parameters are determined from the cusp condition of the wave function. Our calculational results exhibit very fast and good convergence with hyperspherical harmonics (HH) and a generalized Laguerre function (GLF) and substantial improvement over the HH–GLF method. With only 36 HH and 6 GLF, we obtained the ground‐state energy of −2.90371, −7.27988, −13.6555, and −22.0308 au for He, Li+, Be2+, and B3+, respectively. This compares with −2.89361, −7.26131, −13.6253, and −21.9859 au, respectively, by the HH–GLF method and Pekeris' results of −2.90372, −7.27991, −13.6556, and −22.0310 au, respectively. So, the inclusion of 36 HH and 6 GLF has yielded the precision of a few parts in 106 for He, Li+, Be2+, and B3+. However, our calculational results for H− are not so good. We analyzed the cause of this kind of exception and improved our calculations in this respect by using a slightly different correlation function. We finally obtained the ground‐state energy of −0.527754 au for H− with 36 HH and 15 GLF, which is very near Pekeris' result of −0.527751 au and of the same order of precision as those achieved for other He‐like ions. © 1995 John Wiley & Sons, Inc.
Newton–Raphson optimization of the explicitly correlated Gaussian functions for the ground state of the beryllium atom
Authors: Zhang Zhenghong , Adamowicz Ludwik
Published: January 2005

Explicitly correlated Gaussian functions have been used in variational calculations on the ground state of the beryllium atom. In such calculations on systems with more electrons, it becomes imminent and essential to develop effective strategies for optimizing the parameters involved in the basis functions. The theory of analytical first and second derivatives of the variational functional with respect to the Gaussian exponents and its computational implementation in conjunction with the Newton–Raphson optimization technique is described. Some numerical results are presented to illustrate the performance of the method. © 1995 John Wiley & Sons, Inc.
Backscattering effects in Auger electron spectroscopy: A review
Authors: Jabłoński Aleksnder
Published: December 2004

Quantitative Auger electron spectroscopy requires knowledge of a factor correcting for backscattering effects. This paper discusses the definition of the backscattering correction and reviews the experimental and theoretical methods for determining this correction. The values of the backscattering factor reported in the literature are compiled, and the dependence of the backscattering factor on the primary beam incidence angle and the solid composition is also briefly discussed.
Surface characterization and adhesive bonding of stainless steels: II—The Steel/Adhesive Interface
Authors: Gettings M. , Kinloch A. J.
Published: December 2004

In part I of this study the surfaces of three steels were characterized prior to the application of adhesives. In this part of the study the interface region between a silane‐based primer and the surface of the three chemically etched stainless steels was analyzed using a verity of surface‐specific techniques to investigate the chemistry of the primer/metal interaction. These studies were correlated with joint durability studies. It was found that polymerization of the primer was limited and the variation in durability of the joint could be directly related to the amount of interaction between the silicon in the primer and the surface oxide. It appears that the primer/metal interaction was influenced by surface topography and morphology.
Adventitious carbon—the panacea for energy referencing?
Authors: Swift P.
Published: December 2004

A brief historical review has been made of the values assigned to the binding energy of C1s electrons from hydrocarbon contamination on sample surfaces. The particular energy calibration technique used for each electron spectrometer on which the C1s determination was made has been identified. There are notable variations in the C1s electron binding energy for a hydrocarbon contamination layer with respect to the substrate on which it was measured. The possible source and nature of adventitious carbon have been discussed, as have factors which can affect its C1s binding energy value. Sodium phosphate salts have been used to illustrate the relative merits of using an internal energy reference line rather than the C1s electrons from the adventitious carbon layers of these salts. Alternative energy referencing techniques, which include deposition of soot from a candle flame and deliberate ‘in situ’ condensation of a volatile organic compound onto the sample surface, have been compared with the method under review. Another possible method is the mixing of powdered samples with reference compounds (e.g. graphite). It is concluded that, although the use of C1s electrons from adventitious carbon layers is often a convenient method of energy referencing, interpretation of binding energy data obtained should be treated with caution.
Surface studies of keratin fibers and related model compounds using ESCA. I—intermediate oxidation products of the model compound 1‐cystine and their hydrolytical behaviour
Authors: Setiawan L. D. , Baumann H. , Gribbin D.
Published: December 2004

The intermediate oxidation products of 1‐cystine, namely cystine S‐monoxide, cystine S,S‐dioxide and cysteine sulphinic acid have been synthesized according to the procedures of other workers. Attempts to prepare cystine trioxide and cystine tetroxide have also been carried out. The stability of cystine S‐monoxide, cystine S,S‐dioxide and cysteine sulphinic acid in aqueous solutions both under mild hydrolytical conditions (2 h, 25 °C) at different pH values and under the conditions of acid hydrolysis (6 N HCl, 105 °C, 1–20 h, 24 h) have been studied. Cystine, its oxidation products and the disproportionation products are identified by ESCA (C 1s, O 1s, N 1s, S 2p). Both cysteine sulphinic acid and cysteic acid exist mainly as Zwitterions due to the fact that in the carbon spectra of each of them an additional peak shifted to about 1.4 eV (relative to the hydrocarbon peak) has been observed, which is attributed to carbon bond to protonated nitrogen. In addition, only in the cases of cysteine sulphinic acid and cysteic acid an increasing of the nitrogen binding energy of about 1 eV compared with those of cystine and its corresponding oxides has been found indicating of protonated nitrogen. Both the monoxide and the dioxide are relatively unstable in aqueous solutions (2 h, 25 °C, pH 1–10). However the monoxide is more stable than the dioxide under these conditions. Cysteine sulphinic acid is stable under this mild hydrolytical condition. Even in 6 N HCl at 105 °C for 1–20 h in vacuo cysteine sulphinic acid is moderately stable. After 24 h it cannot be detected at all. The results achieved from these studies are discussed in detail in conjunction with previous results reported by other investigators concerning the hydrolytical behaviour of cystine intermediate oxidation products.
Application of elastic peak electron spectroscopy (EPES) to determine inelastic mean free paths (IMFP) of electrons in copper and silver
Authors: Doliński W. , Nowicki H. , Mróz S.
Published: December 2004

Elastic peak electron spectroscopy (EPES) is used for determination of inelastic mean free paths in silver and copper for electrons with energy of 250, 500, 1000 and 1500 eV. Namely, the elastic scattering coefficient ηe is measured with a retarding field analyser (LEED optics) and calculated by computer simulation for different values of the inelastic mean free path λ. A value of λ giving the best fit for the measured and calculated ηe is taken as the experimental inelastic mean free path. Results obtained are in agreement with those known from the literature. Equivalency between the values of ηe obtained by analytic calculation and by computer simulation is found.
Evaluation and measurement of changes in intensity of the characteristic lines and background of Auger electron spectra due to crystalline effects. Application to an aluminium target bombarded with electrons
Authors: Akamatsu B. , Henoc P. , Maurice F. , Le Gressus C. , Raouadi K. , Sekine T. , Sakai T.
Published: December 2004

We evaluated and measured the influence of channelling on changes in intensity of the characteristic lines and background of Auger electron spectra by performing calculations and experiments on an aluminium single crystal.

Propagation of the incident beam in the crystal was calculated by the dynamic theory of electron diffraction, while the Monte‐Carlo method was used to simulate electron paths in the material as a function of experimental conditions.

We measured the contrasts of the Al LVV (68 eV) and Al KLL (1396 eV) lines in both channelling and abnormal absorption positions and we recorded the background of the En(E) curves for different electron accelerating voltages and for some strong reflections.

The theoretical and experimental results are consistent, revealing the magnitude of crystalline effects in AES. These effects, although they are a hindrance in routine analysis, can be used to study changes in the surface layer composition of metals and ceramics.
Charge compensation and high‐resolution TOFSIMS imaging of insulating materials
Authors: Briggs D. , Hearn M. J. , Fletcher I. W. , Waugh A. R. , McIntosh B. J.
Published: December 2004

A charge compensation system, based on a pulsed lowenergy electron flood source, designed for the 1X23S time‐of‐flight secondary ion mass spectrometry (TOFSIMS) instrument is described. Its performance in the non‐imaging mode is illustrated by spectra from polytetrafluoroethene (PTFE). High‐resolution (∼1 pm) imaging of challenging insulating samples under near‐static SIMS conditions is demonstrated for the first time.
Determination of peak positions and areas from wide‐scan XPS spectra
Authors: Turner N. H. , Single A. M.
Published: December 2004

It has been found that by taking transforms of both Gaussian and Lorentzian line shapes into polynomial representations, it is possible in many instances to determine peak position, peak intensity and the full‐width at half‐maximum (FWHM) from wide‐scan XPS spectra that have a low number of data points per electron‐volt. This approach was tested with several samples, ranging from an insulator, Al2O3, to an excellent conductor, sputter‐cleaned gold. Several data sets were constructed from narrow‐scan spectra with points selected about 1 eV apart to simulate wide‐scan spectra. Then, comparisons were made between values calculated with a non‐linear least‐squares fit that used all of the data points from a given spectrum, and the polynomial procedure with the simulated wide‐scan data. It was found that the peak positions usually agreed to within 0.1 eV between the methods. The FWHM and intensities agreed to ∼20%. The area ratios usually were within ∼10%. Comparisons between actual and simulated wide‐scan data showed similar area ratio agreement. However, there appeared to be a systematic difference in the peak position of ∼0.5 eV, which was due to the spectrometer used in this study. Thus, in many cases, estimates of the relative atomic amounts can be made with those results from the polynomial procedure that would be comparable to those obtained from non‐linear least‐squares analysis of narrow‐scan data. The effects of such factors as baseline, overlapping peaks, computational techniques and line shape on the use of the polynomial method are discussed also.
Ion microprobe for studying cluster ion decay reactions
Authors: Bekkerman A. D. , Dzhemilev N. Kh. , Rotstein V. M.
Published: December 2004

In the present paper, an ion microprobe is used to study the fragmentation regularities of Aln+ and Sin+ cluster ions sputtered under ion bombardment. The results have shown that the ions formed during cluster fragmentation, along the path from the target to the detector, transform the mass spectra of both charged and neutral components and the energy distribution of the parent cluster and monomer ions.
Escape depth of photoelectrons
Authors: Jablonski Aleksander
Published: December 2004

The sampling depth of electron spectroscopies, AES and XPS, is frequently directly associated with the value of the inelastic mean free path (IMFP). Owing to elastic scattering of signal electrons, a separate parameter, the escape depth (ED), should be used to describe the analysed volume. There is no simple relation between the ED and the IMFP. In the present work, extensive Monte Carlo calculations were performed to calculate the ED for photoelectrons emitted from gold (Au 4s, Au 4p3/2, Au 4d5/2 and Au 4f7/2). All XPS configurations within a plane normal to the surface were considered. It has been found that the anisotropy of photoelectron emission is strongly reflected in the angular dependences of the ED. Furthermore, the value of ED divided by the cosine of the detection angle, which is equivalent to the attenuation length (AL) described by one of the definitions, may considerably exceed the IMFP, in contrast with common expectations. This occurs at large detection angles and/or in experimental configurations with the direction of x‐rays close to the direction towards the analyser. A simple and accurate parameterization was proposed in the present work, taking into account the anisotropy of photoemission, from which the ED can be predicted for photoelectrons considered and for any XPS configuration.
Potential applications of hyperthermal atomic oxygen for treatment of materials and structures
Authors: Kleiman J. I. , Iskanderova Z. A. , Gudimenko Y. I. , Tennyson R. C.
Published: December 2004

Many polymer‐based materials degrade in low earth orbit (LEO), mainly due to the damaging environmental effects of hyperthermal or fast atomic oxygen of energy E ∼ 5 eV and solar vacuum ultraviolet radiation. Fast atomic oxygen fluxes of similar energies are generated now in ground‐based facilities that are used for accelerated testing of materials.

This paper presents a brief overview of the effects of interaction of fast atomic oxygen fluxes with polymer‐based materials in the LEO space environment and in ground‐based simulators, and discusses a few possible applications of fast atomic oxygen fluxes. Such applications can lead to considerable advantages over plasma treatment, aimed at improvement of adhesion‐related and optical properties of polymer‐based materials, high‐quality precise photoresist etching and passivative oxidation of advanced semiconductor materials, and modified or entirely new surface properties of biomaterials and chemical sensors.
NIST oxide‐marker‐layer standard reference material (SRM 2136) for depth profile analysis
Authors: Fine Joseph , Navinsek Boris
Published: December 2004

A chromium thin‐film structure containing thin oxide layers was developed specifically for secondary ion mass spectrometry calibration of sputtered depths and erosion rates. Information on its structure and characterization is summarized. It is available from NIST as Standard Reference Material 2136.
Molecular Printboards on Silicon Oxide: Lithographic Patterning of Cyclodextrin Monolayers with Multivalent, Fluorescent Guest Molecules
Authors: Mulder Alart , Onclin Steffen , Péter Mária , Hoogenboom Jacob P. , Beijleveld Hans , ter Maat Jurjen , García‐Parajó María F. , Ravoo Bart Jan , Huskens Jurriaan , van Hulst Niek F. , Reinhoudt David N.
Published: December 2004

Three compounds bearing multiple adamantyl guest moieties and a fluorescent dye have been synthesized for the supramolecular patterning of β‐cyclodextrin (CD) host monolayers on silicon oxide using microcontact printing and dip‐pen nanolithography. Patterns created on monolayers on glass were viewed by laser scanning confocal microscopy. Semi‐quantitative analysis of the patterns showed that with microcontact printing approximately a single monolayer of guest molecules is transferred. Exposure to different rinsing procedures showed the stability of the patterns to be governed by specific supramolecular multivalent interactions. Patterns of the guest molecules created at CD monolayers were stable towards thorough rinsing with water, whereas similar patterns created on poly(ethylene glycol) (PEG) reference monolayers were instantly removed. The patterns on CD monolayers displayed long‐term stability when stored under N2, whereas patterns at PEG monolayers faded within a few weeks due to the diffusion of fluorescent molecules across the surface. Assemblies at CD monolayers could be mostly removed by rinsing with a concentrated CD solution, demonstrating the reversibility of the methodology. Patterns consisting of different guest molecules were produced by microcontact printing of one guest molecule and specific adsorption of a second guest molecule from solution to non‐contacted areas, giving well‐defined alternating assemblies. Fluorescent features of sub‐micrometer dimensions were written using supramolecular dip‐pen nanolithography.
Poly(dimethylsiloxane) sealant with improved properties by blending with vinyl polymers
Authors: Blaga A. , Beznaczuk L. M. , Feldman D.
Published: December 2004

Novel adhesive sealants with markedly improved mechanical and durability properties have been prepared by blending poly(dimethylsiloxane) with PVC or (VAc‐VC) copolymer. The effect of blending with the vinyl‐type polymer, the influence of three types of substrates (California redwood, aluminum, or Portland cement mortar), and the effect of weathering on the properties of the PDS or the resulting products were assessed by stress‐strain testing and toughness determinations. The morphology of unblended PDS and the PDS‐based blends was studied by SEM observation in conjunction with EDXA and DSC measurements. Results have indicated considerable improvement in mechanical properties and enhanced weathering resistance in some of the blends used in conjunction with either wood or aluminum substrates.
Zur Kenntnis der Stickstoffquecksilberverbindungen
Authors: Pesci L.
Published: January 2005

Aus dem im vorstehenden Gesagten kann man den Schluss ziehen, dass die Tatsachen die Theorie bestätigen, nach welcher nur ein einziger Typus von Merkuriammoniumsalzen, und zwar Hg2 N‐X, angenommen wird. Diese Salze leiten sich von dem Hydroxyd Hg2 NOH ab und geben besonders leicht mit den Ammoniumsalzen komplexe Verbindungen, wie die weissen Präcipitate
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und dir anderen Doppelsalze
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Die Absorption. 5. Abhandlung. Die Absorption von HCl und KCl aus wässeriger Lösung durch kolloïdales Zinnoxyd
Authors: Van Bemmelen J. M. , Klobbie E. A.
Published: January 2005

Die Absorption von HCl und von KCl (KNO3, K2SO4) durch die kolloïdale sogenannte Metazinnsäure hat die Ergebnisse meiner früheren Versuche über die Absorption von krystalloïdalen Säuren, Basen, Salzen aus ihren wässerigen Lösungen durch Kolloïde bestätigt.
Über ein saures Tripelsalz
Authors: Meyerhoffer W. , Cottrell F. G.
Published: January 2005

Es wurde das Hydrolangbeinitsulfatdihydrat KHMg(SO4)2.2H2O dargestellt und die Zusammensetzung der mit ihm nnd Schönit in Berührung befindlichen Lösung bei 25° ermittelt.
Kupfer und Sauerstoff
Authors: Heyn E.
Published: January 2005

1. Die Erstarrung der Lösungen von Kupferoxydul in Kupfer erfolgt nach der Erstarrungsart 5, im besonderen nach Art 5a oder 5b nach BAKHUIS ROOZEBOOM. Die Löslichkeit des Kupfers gegenüber Kupferoxydul wird mit dem Übergang aus dem flüssigen in den festen Aggregatzustand praktisch gleich Null. Nach der Erstarrung hat also eine Trennung zwischen Kupfer und Kupferoxydul stattgefunden; es bestehen zwei feste Phasen, reines Kupfer und kupferoxydulreicher Körper (aller Voraussicht nach Kupferoxydnl selbst). Das reine Kupfer hat einen einheitlichen Erstarrungspunkt von 1103°C.1 Die eutektische Legierung mit 3.4—3.5 % Oxydul hat einen einheitlichen Erstarrungspunkt bei 1084 °C.1 Alle übrigen Legierungen haben eine sich über mehrere Wärmegrade erstreckende allmähliche Erstarrung, deren unterer Endpunkt bei 1084 °C. liegt. Der Beginn der Erstarrung wird durch das Kupferoxydul bis zu einem Gehalt von 3.4 % herabgedrückt, und bei weiter steigenden Gehalten wieder stark nach oben verschoben. Die Berechnung der Schmelzpunktserniedrigung nach der RAOULT, VAN'T HOFFschen Formel für verdünnte Lösung stimmt mit der Beobachtung überein.

2. Abschreckung von zwischen Beginn und Ende der Erstarrung liegenden Warmegraden kann die Festhaltung des Kupferoxyduls im Kupfer im gelösten Zustande bei gewöhnlichen Wärmegraden nicht bewirken.

3. Die zwei festen Phasen in den erstarrten Legierungen von Kupfer und Kupferoxydul verteilen sich auf 3 Gefügeelemente: a) oxydulfreies Kupfer in Form rundlicher Kristalliten. b) Kristalliten von Kupferoxydul, von grösserer Härte als Kupfer, von blauer Farbe im zurückgeworfenen und cochenilleroter Farbe im durchfallenden Licht. c) Eutektisches Gemenge von a und b in feinster Verteilung. Legierungen mit weniger als 3.4% Oxydul bestehen aus a + e, solche mit 3.4–3.5% dieses Körpers nur aus e, und solche mit noch höheren Gehalten aus b + e.
Über die Reduktion der gebundenen, festen Kohlensäure zu Kohlenstoff und über elektrochemische Veränderungen bei festen Stoffen
Authors: Haber F. , Tołłoczko St.
Published: January 2005

Es wurde die Elektrolyse fester Elektrolyte ausgeführt.
Über die elektrolytische Bestimmung und Trennung von Antimon und Zinn aus ihren Sulfosalzlösungen nebst einem Anhange über die Trisulfidmethode des Antimons
Authors: Fischer Arthur
Published: January 2005

Die Hauptresultate der vorliegenden Untersuchungen sind:

1. Die elektrolytische Reduktion von Zinn gelingt sehr leicht aus der Lösung des Zinnammoniumsulfosalzes, unter Anwendung einer zuvor verzinnten Platinkathode, bei Zusatz von Natriumsulfit zum Schwefelammonium und ergibt alsdann genaue Resultate. Es empfiehlt sich hierbei die Anwendung einer Platiniridiumanode.

2. Antimon lässt sich sowohl aus dem Sulfantimonit wie aus dem Sulfantimoniat in Schwefe1natriumlösung unter Zusatz von Cyankalium als reines Metall quantitativ abscheiden. Die Gegenwart von Polysulfiden vor der Elektrolyse ist ohne Belang, da deren Reduktion durch Cyankalium leicht gelingt. Eine Platiniridiumanode ist auch Zier einer Platinanode vorzuziehen.

3. Das elektrochemische Äquivalent des Antimons in Sulfantimonit ist \documentclass{article}\pagestyle{empty}\begin{document}${{{\rm Sb}} \over {\rm 3}}$\end{document}, in Sulfantimoniat: \documentclass{article}\pagestyle{empty}\begin{document}${{{\rm Sb}} \over {\rm 5}}$\end{document}. Fünfwertigkeit des Antimons begünstigt die Umkehr der Reaktion, wahrend Dreiwertigkeit sie hinausschiebt.
Über die Bildung von Ammoniak den Elementen
Authors: Haber F. , van Oordt G.
Published: January 2005

Die in der vorläufigen Mitteilung von uns beschriebene Bestimmung des Ammoniakgleichgewichtes bei 1020° C. wurde genauer dargestellt. Im Anschluss daran wurde die Berechnung der freien Bildungsenergie des Ammoniaks versucht, die für den Ammoniakgehalt einer im Gleichgewicht befindlichen Stickstoff‐, Wasserstoff‐ und Ammoniakmischung bei einer Atmosphäre Druck die folgenden Werte lieferten:

Diese Zahlen beanspruchen indessen keine grosse Genauigkeit.
Revision des Atomgewichtes von Jod. (Zweite Mitteilung)
Authors: Baxter Gregory Paul
Published: January 2005

Die Ergebnisse dieser Untersuchung sind die folgenden:

Das Atomgewicht des Jods wurde zu 126.985 (Ag = 107.930) gefunden, 1/100 Einheit höher als der früher erhaltene Wert. Wird Silber zu 107.920 angenommen und Sauerstoff zu 16.000, so wird das Atomgewicht von Jod 126.973.

Die Beobachtung von KÖTHNER und AEUER, dass unter gewissen Bedingungen Silbernitrat von Silberjodid eingeschlossen wird und dass das erstere durch Waschen nicht entfernt werden kann, wurde bestätigt.

RICHARDS und WELLS wert für das Atomgewicht des Chlors 35.473 hat eine neue Stütze erhalten.
Revision der Atomgewichte von Natrium und Chlor
Authors: Richards Theodore William , Wells Roger Clark
Published: January 2005

S. 56. – Wage und Gewichte. S. 63. –Herstellung reiner Materialien: S. 65. Wasser; Chlorwasserstoffsäure; Natriumchlorid; Silber; Kalk; Utensilien. – Die Löslichkeit von Silberchlorid. S. 82. – Die Okklusion von gelösten Substanzen durch Silberchlorid. S. 88. – Das Verhältnis von Natriumchlorid zu Silberchlorid. S. 93. – Das Verhältnis von Natriumchlorid zu Silber. S. 105. – Das Schmelzen von Natriumchlorid im Vakuum. S. 117. – Synthese des Silberchlorids. S. 119. – Die neuen Atomgewichte von Natrium und Chlor und ihr Einfluss auf andere Atomgewichte. S. 131. – Zusammenfassung. S. 133.
Über die Einwirkung von Wasserstoffsuperoxyd auf Wismutsalze
Authors: Moser L.
Published: January 2005

Der aus Wismutlösungen durch Wasserstoffsuperoxyd in alkalischer Flüssigkeit erhaltene Körper ist kein höheres Oxyd des Wismuts, sondern entspricht dem basischen Hydroxyd, dem die Formel BiO.OH zukommt. Ausserdem fällt in geringer Menge basisches Wismutnitrat heraus, welcher Vorgang dann eintritt, wenn Wismutsalze in saurer Lösung mit Alkali versetzt werden.
Thalliumoxyde. II. Abhandlung
Authors: Rabe Otto
Published: January 2005

Thallioxyd, das in einem gewöhnlichen Trockenkasten erhitzt wird, zeigt eine Gewichtszunahme, deren Endwert hauptsächlich von der Dauer des Erhitzens abhängt.
Metallographische Mitteilungen aus dem Institut für anorganische Chemie der Universität Göttingen. XXXV. Über Antimon‐Kadmiumlegierungen
Authors: Treitschke W.
Published: January 2005

Antimon und Kadmium bilden also zwei Verbindungen miteinander, von denen die eine, die absolut stabile, die Formel SbCd und die andere nicht stabile wahrscheinlich die Formel Sb2Cd3 hat. Die Verbindung Sb2Cd3 und die ihr zugehörige Reihe von Mischkristallen scheidet sich spontan aus allen Schmelzen von 30–100 % Sb aus. Das Endglied dieser Reihe von Mischkristallen, der gesättigte Mischkristall b mit 53 % Sb, ist in allen spontan kristallisierten Konglomeraten von 100–53 % Sb neben primär ausgeschiedenem Antimon vorhanden. Von 50–8 % Antimon wurde nie die spontane Kristallisation der Verbindung Sb2Cd3 beobachtet, sondern es kristallisierte immer aus diesen Schmelzen die absolut stabile Verbindung SbCd in ihren charakteristischen langen Säulen. Bei schneller Abkühlung (Abschreckung) gelingt es, diese Verbindung Sb2Cd3 und ihre Mischkristalle auch in den antimonreicheren Reguli mit mehr als 42 % Sb zu fixieren.
Über die Platosalze einiger schwefelhaltigen Organischen Säuren
Authors: Ramberg Ludwig
Published: January 2005

Die oben beschriebenen Verbindungen sind sämtlich wie Salze des zweiwertigen Platins zusammengesetzt. Wie nicht anders zu erwarten war, zeigen sie aber keineswegs den Charakter normaler Salze, sondern sind in hohem Grade komplex. Es unterliegt wohl kaum einem Zweifel, dass sie diese Eigenschaft, wie überhaupt ihre Existenz, den „Nebenvalenzen”︁ des Schwefels verdanken. Übrigens kann man unter ihnen zwei scharf getrennte Klassen unterscheiden. Zur ersten gehört das Xanthogenat, das durch gelbe Farbe, Unlöslichkeit in Wasser, Löslichkeit in Chloroform und Benzol an die Platosulfinverbindungen erinnert und keine Fähigkeit besitzt, Ammoniak oder Halogenwasserstoff zu addieren, was damit zusammenhängen dürfte. dass die Xanthogensäure zwei Schwefelatome im Molelkül besitzt, von denen jedenfalls das eine durch direkte Valenzbindung mit dem Platin verkettet ist. Die zweite Klasse umfasst die Derivate von Säuren mit einem Atom Schwefel im Molekül. Sie sind mehr oder weniger grünlich gefärbt, lösen sich, wenn auch zuweilen spärlich, in Wasser, dagegen nicht in Chloroform, und zeichnen sich durch ihre Additionsfähigkeit Ammoniak und Halogenwasserstoff gegenüber aus. Die Derivate der Äthyl‐ und Phenylthioglykolsäure sind den Platinverbindungen des Glykokolls und des Acetylacetons analog, während das Derivat der Thiodiglykolsäure an die Platooxalsäure von SODERBAUM erinnert.
Über die Kaustizierung von Natriumkarbonat und Kaliumkarbonat mit Kalk
Authors: Le Blanc M. , Novotný K.
Published: January 2005

1. Die Löslichkeit und die hydrolytische Spaltung des CaCO3 wurden bei 18° und 100° bestimmt.
Beiträge zum Studium der Calciumphosphate. II. Die Einwirkung von Ammoniakgas auf Calcium‐Hydroorthophosphate
Authors: Bassett Henry
Published: January 2005

CaHPO4 reagiert nicht mit Ammoniak, weder bei gewöhnlicher Temperatur noch bei 100°.
Über das Kupfersuperoxyd
Authors: Moser L.
Published: January 2005

Die einzige Methode, um Kupfersuperoxyd CuO2.H2O zu erhalten, besteht in der Oxydation von fein verteiltem Kupferoxydhydrat durch Wasserstoffsuperoxyd (15–30%) in neutraler Lösung, wobei die Temperatur nahe dem 0‐Punkte sein soll. Im feuchten Zustande zerfällt das Kupfersuperoxyd rasch unter Abgabe von Sauerstoff und Wasser, trocken geht dieser Zerfall nur langsam vor sich. Durch die Einwirkung von Chlor und Brom in alkalischer Lösung wird nur Kupferoxyd erhalten und sind die gegenteiligen Angaben von Krüger und Vitali unrichtig. Auch Persulfate bewirken in alkalischer Lösung keine Oxydation in Cuprisalzen. Durch Natriumsuperoxyd entsteht zwar Kupfersuperoxyd, doch tritt infolge der alkalischen Flüssigkeit ein außerordentlich rascher Zerfall desselben ein. Schliefslich ist die Beobachtung von W. Schmid unrichtig, der durch Behandlung von Cuprisulfat mit Mangansuperoxyd Kupfersuperoxyd erhalten haben will.
Studien über Thalliumoxyde. (III. Teil.)
Authors: Rabe Otto
Published: January 2005

Die Ergebnisse der vorstehenden Arbeit sind zusammengefafst die folgenden: Fein krystallines aus Thallosalzen und Hydro‐peroxyd entstehendes Thallioxyd (Tl2O3) enthälttatsächlich, auch nach dem Trocknen im Vakuum über Phosphorpent‐oxyd bis zur Gewichtskonstanz, noch geringe Mengen Wassers, wie schon in den beiden ersten Abhandlungen1 auf Grund der dort beobachteten kleinen Abweichungen des gefundenen Thalliumgehaltes von dem für Tl2O3 berech‐neten a priori angenommen wurde. Dieses Wasser wurde sowohl indirekt durch den Gewichtsverlust der Oxyde bei dem Erhitzen wie auch direkt durch Auffangen und Wägen im Chlorcalciumrohr bestimmt. Der Wassergehalt betrug im vorliegenden Falle 0.77% bei dem hraunen und 0.23% bei dem schwarzen Oxyd. Es ist wohl nicht zulässig, dieses Wasser als ein im gewöhnlichen Sinne chemisch gebundenes (Hydratwasser) anzusprechen. Dagegen spricht schon seine geringe Menge, die in den bier untersuchten Proben nur 1/5 bzw. 1/15 derjenigen betrug, die nach der Berechnung bereits für ein Thallioxydmonohgdrat (Tl2O3·H2O) erforderlich ist (3.79%). Der naheliegende Einwand, dass durch die vorhergehende Trocknung über Phosphorpentoxyd der Hauptteil des Hydratwassers schon entfernt wird, ist nicht stichhaltig. Denn der Betrag an Wasser, der dadurch entfernt wird, betrug beispielsweise in einem früheren Versuche2 mit dem braunen Oxyd (also dem an sich etwas wasserreicheren Produkt) auch nur 0.29%. Die beiden Oxydformen werden also gleich bei der Darstellung in einem sehr wasserarmen Zustand gewonnen.
Die Bestimmung von Molekelgewichten durch Verteilungsversuche
Authors: Coehn Alfred , Livingston J. , Morgan R. , Benson H. K.
Published: January 2005

1. Die Molekulargewichte von Essigsäure und Äthylalkohol in Äther sind dieselben wie in Wasser, d. h. Cw/Ce für Essigsäure und Alkohol is t konstant und unabhängig von der Verdünnung.
Beiträge zur Kenntnis der Silicate VII. Über die Verbindungen der Kieselsäure mit Alkali und über die Darstellung krystallisierter Natriumsilicat
Authors: Jordis Eduard
Published: January 2005

1. Bei der Bildung von Alkalisilicaten im Schmelzfluss aus Sand und Soda entsteht ein Gleichgewichtszustand zwischen CO3″ und SiO″, abhängig von der Masse der Komponenten und der Temperatur; ebenso bei der Darstellung auf wässerigem Wege, bei der noch die Konzentration mitspricht. Alkalilauge löst einfach die Kieselsäure, aber nicht in stöchiometrischem Verhältnie. Die Angaben der Literatur lassen sich aus diesen Gesichtspunkten erklären.
Über die Legierungen des Kupfers mit Kobalt, Eisen, Mangan und Magnesium
Authors: Sahmen R.
Published: January 2005

1. Alle vier untersuchten Metallpaare – Kobal‐Kupfer, Eisen‐Kupfer, Mangan‐Kupfer und Magnesium‐Kupfer – sind im geschmolzenen Zustande in allen Verhältaissen mischbar.
Über die Legierungen des Calciums mit Zink, Cadmium, Aluminium, Thallium, Blei, Zinn, Wismut, Antimon und Kupfer
Authors: Donski L.
Published: January 2005

Calcium zeichnet sich duroh seine hohe Verbindungsfähigkeit aua. Es bildet mit den von mir untersuchten Metalien folgende Verbindungen:
equation image

Anch die Bildung einer Verbindung mit Antimon ist höchst wahrscheinlich, doch konnte ich die Zusammensetzung diem Verbindung, sowie der Wismutverbindung, nicht feststellen.
Anormales Verhalten bei der Hydrolyse der Salze von Zn, Mg, Th, Ce, Ni und Co
Authors: Denham Henry George
Published: January 2005

Die Wasserstoffelektrode ist benutzt worden, die Veränderungen der prozentischen Hydrolyse verschiedener Salzlösungen zu verfolgen, und zwar insbosondere beim Zinksulfat und ‐chlorid, beim Magnesiumsulfat, Cerochlorid, Thoriumsulfat, Nickelsulfat und Kobaltchlorid.
Eine neue Oxydationsstufe des Palladiums
Authors: Wöhler Lothar , Martin Friedr
Published: January 2005

1. Es wurde das bisher unbekannte Palladiumsesquioxydhydrat, Pd2O3 ·xH2O, als Primiirprodulrt der Elektrolyse von Palladiumoxydulnitrat sowie seiner Oxydatiou mittels Ozon in deutlich saurer Lösung hergestellt. Die Bedingungen seiner Reindarstellung und seiner Zusammensetzung wurden gegeben, die weitere sekundare Umwandlung des primaren Sesquiouyds in Dioxyd durch freiwilligen Zerfall des, ersteren in Dioxyd und Oxydul dargetan.
Bekannte und neue Subhaloide
Authors: Wöhler Lothar , Rodewald G.
Published: January 2005

1. Das Silbersubfluorid wurde in mehreren Darstellungen nach GUNTZ als Produkt der konstanten chemischen Zusammensetzung Ag2F erhalten und damit als wirkliche chemische Verbindung charakterisiert.