bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mass Spectrometry of Ions in Glow Discharges. I. Apparatus and Its Application to the Positive Column in Rare Gases
Authors: Knewstubb P. F. , Tickner A. W. 
Published: January 2005

An apparatus is described which samples and analyzes ions from a glow discharge. Results are given for the positive column of discharges in argon, krypton, and mixtures of the two, at pressures between 0.4 and 1.0 mm and current densities in the range 0.035 to 0.105 ma/cm2. In general, the results are in reasonable agreement with those of other workers, but some differences are noted.
The results appear to favor the formation of A2+ by the reaction Ar*+Ar→A2++e, but it is not possible to rule out conclusively the three-body process Ar++2Ar→Ar2++Ar. Traces of hydrogenous impurities (especially water) appear to interfere with molecule ion formation.
The formation of ArH+ from impurities is also studied and the results suggest that it may be formed from any or all of Ar+, Ar2+ or Ar*. Experiments in which 1.25% hydrogen is added to the argon suggest that ArH+ is not formed mainly by the reaction of Ar+ with H2 but that the reaction of metastable argon atoms with hydrogen atoms should be seriously considered.
The visible structure of a striated positive column is found to be reflected in the ion concentrations which vary differently for different ions. The effect seems to be related to fluctuations in the potential gradient which may be enhanced by the formation of negative ions.
Effect of Reactor Length on the Formation of Detonation in Saturated Knallgas-Steam Mixtures
Authors: Luker James A. , Adler Leonard B. 
Published: January 2005

Reactor length is an external variable governing the formation of detonation in certain gaseous mixtures which has received only limited attention.
Data presented herein show a qualitative relationship between reactor length and the effect of end-reflected precompressional shock waves on the deflagration process. Within a specific length range for certain gaseous mixtures, shortening the reactor may enhance the formation of detonation while lengthening the reactor will retard the reflection effects which accelerate the predetonation flame. For proper experimental definition of the formation of detonation in mixtures exhibiting long induction distances, reactor length must be considered along with the other major external variables.
Electrical Conductivity of Proteins. II. Semiconduction in Crystalline Bovine Hemoglobin
Authors: Rosenberg Barnett 
Published: January 2005

Evidence has been presented to show that crystalline bovine hemoglobin is a semiconductor in the dry state. The semiconduction activation energy is 2.3 ev. This is similar to the values obtained for a number of other proteins, chromoproteins, and biological structures which have proteins as the main constituent. The effect of adsorbed water is to increase the conductivity enormously. The dependence on the amount of adsorbed water is exponential, in agreement with the results of Baxter and Spivey. In the ``wet'' state, the protein is still a semiconductor, but the semiconduction activation energy is lower. The dependence of the activation energy on the amount of adsorbed water is given by EW=ED−δm.It has been proved that this is the only effect of water in causing the increase in conductivity. The value of σ0 in the semiconduction formula is 7×103[Ω—cm]—1 and is independent of the adsorbed water content. The effect of water adsorption on the conductivity is reversible when the water is desorbed. Experimental evidence, which strongly indicates that the conductivity process in the wet protein is electronic rather than ionic, has been given previously by the writer.
A theory is developed which shows that the effect of adsorbed water in increasing the dielectric constant of the protein lowers the work necessary to separate the charges due to the increase in the polarizability of the medium. This leads to a prediction that the dependence of the dielectric constant on the adsorbed water content should be of the form κ′=κ/(1−κχm).Some previous measurements of Medley and King are in semiquantitative agreement with this. The theory also predicts that for higher adsorbate concentrations, the conductivity should become constant (saturation effect). Again, the measurements of Medley and King confirm this. This saturation effect allows an estimate to be made of the radius of the polarization (R) and the ionization energy minus the electron affinity (I — A) for the protein. R≈2.8×10—8 cm and I — A≅10 ev. Both values are in reasonable agreement with expectations.
Raman Spectral Studies of the Effects of Electrolytes on Water
Authors: Walrafen George E. 
Published: January 2005

Photoelectric Raman spectra of water at temperatures from 2° to 94°C have been obtained for the spectral region of about 0–4000 cm—1. Comparisons of these spectra, with Raman spectra of bromide and chloride solutions, indicate that certain intensities, which are increased by lowering the temperature of water, are also increased by electrolyte addition. Such intensity increases of Raman bands of the bromide and chloride solutions appear to be related to the ordering of water and ions. Other Raman bands of water, for which intensity increases occur with lowering of temperature, decrease in intensity with electrolyte addition. Those effects apparently are related to O–H···O bonds.
The intensities of various bands studied, e.g., the librational bands, were observed to increase linearly with electrolyte concentration. In addition, marked intensity increases with increasing anionic size, i.e., Br—&gt;Cl—, were observed, but the effects of the cations, while similar with respect to increasing size, appear to be relatively small.
The linear intensity increases have been explained in terms of the concentration of ordered water-electrolyte units. The size effects have been considered in terms of the polarities of the bonds of those units.
Structure and Surface Binding: N and CO on Tungsten
Authors: Ehrlich Gert 
Published: January 2005

The energetics of the interactions of N2 and CO with initially clean tungsten surfaces are analyzed to establish the dependence of chemisorption upon surface structure. For N2, calorimetric measurements yield a heat of adsorption of ∼90 kcal mole—1, constant over the range of coverages accessible at T=300°K. This suggests that the equilibrium binding sites for nitrogen are energetically equivalent. Desorption obeys bimolecular kinetics, with an activation energy of ∼81 kcal mole—1, unchanging to the highest surface concentrations (n∼250×1012 molecules cm—2).
This constancy confirms the energetic equivalence of the surface sites filled by nitrogen, and demonstrates the presence of adatoms without lateral interactions. Alternative proposals for the occupation of binding sites of different strengths are examined and rejected as caused by experimental error.
In contrast, evolution of CO takes place in distinct steps, with activation energies of 53, 75, and ∼100 kcal mole—1 for β material. Stepwise desorption stems from the arrangement of CO binding sites. These differ in strength, are widely separated from one another, and presumably consist of planes with different crystallographic orientation.
Despite the constant heat of adsorption, the presence of an activation barrier to surface diffusion, amounting to ∼35 kcal mole—1 on the approaches to the (100), demonstrates that binding of nitrogen atoms does depend on surface structure. In the regions between equilibrium sites, a nitrogen adatom is less firmly bound. On the (110) planes, in which each tungsten atom has six nearest neighbors, the binding energy of a nitrogen adatom is lowered to such an extent that at room temperature these areas should be bare. This is confirmed by direct observation in the field ion microscope. Such ``structural exclusion'' arises from the high dissociation energy of N2, which precludes occupation of sites accessible to other, less strongly bonded molecules. For nitrogen atoms only a narrow band in the total spectrum of binding energies is available. Structural exclusion is also shown to be in accord with the following unique properties of nitrogen layers: (1) The limited concentration (∼40% of the total number of surface sites) achievable at room temperature; (2) The presence of an additional and heavily populated binding state (γ) at T&lt;200°K; (3) The absence of interactions between adatoms.
On the Use of Nonintegral Exponents in Elliptical Coordinate Wave Functions, with Special Reference to the Hydrogen Molecule-Ion
Authors: Geller Murray , Ludwig Oliver G. 
Published: January 2005

Introduction of arbitrary powers of the elliptical coordinate μ is shown to give a better approximate wave function for the hydrogen molecule-ion than any previous function of comparable complexity. The three-parameter two-configuration functionψ=Nμne−αμ(1+bν2)is found to give an energy of —0.602566 a.u. and an equilibrium internuclear separation of 1.9956 a0 compared with the results for n=0 of —0.602386 a.u. and 1.9966 a0, respectively, and with the exact values of —0.60263 a.u. and 2.0 a0, respectively. This agreement is maintained over a range of internuclear distances.
In the Appendix a discussion is given of various methods for computing kinetic energy integrals, and a special difficulty is pointed out that arises when functions in prolate spheroidal coordinates are employed.
Vacuum Ultraviolet Absorption Spectra of 1,4-Dioxane and 1,3-Dioxane
Authors: Hernandez G. J. , Duncan A. B. F. 
Published: January 2005

The spectrum of 1,4-dioxane shows strong absorption regions with intensity maxima at 55 500, 63 000, 69 500, and 72 000 cm—1, and an absorption region whose maxima is obscured by the last two absorption regions. A first ionization potential was located at 76 750 cm—1 (9.52 ev) which agrees with the value determined by electron impact (9.52 ev). The first electronic transition shows considerable virbrational structure, and the analysis of this structure indicates that the upper-state vibrational frequencies are only slightly changed from those of the normal state. The other electronic transitions form a possible Rydberg series which converges to the first ionization potential.
1,3-dioxane shows an absorption region with a maximum at 62 500 cm—1, and another very strong continuous absorption region beginning at about 67 500 cm—1. There is no apparent discontinuity in the region of the ionization potential. The electronic spectrum of 1,3-dioxane showed no vibrational structure.
Chemical Processes Subsequent to n—π* and π—π* Transitions of Pyridine N-oxide and 2-Picoline N-oxide
Authors: Hata Norisuke , Tanaka Ikuzo 
Published: January 2005

The gaseous photolysis of pyridine N-oxide was carried out by irradiating with the 3261 A (Cd) or 2537 A (Hg) resonance line which corresponds to the absorption due to an n—π* or a π—π* transition of this substance, respectively. The main product was pyridine in both cases. However, there exists a remarkable difference in the relation between the quantum yield of pyridine produced and the temperature. In the case of 3261 A irradiation the quantum yield of pyridine increases steeply at temperatures greater than 80°C, which means that an activation energy would be required for the production of pyridine. On the other hand, the quantum yield of pyridine produced at 2537 A irradiation was nearly independent of the temperature. The activation energy necessary for the production of pyridine in the case of 3261 A irradiation is about 11.9 kcal mol—1, which was estimated from the temperature-dependence of the quantum yield of pyridine. The chemical processes succeeding to an n—π* or a π—π* transition of pyridine N-oxide were interpreted under the assumption that the excited molecule dissociates to pyridine and atomic oxygen in a predissociative manner, in which a triplet state crossing with the first excited state exists as a short-lived intermediate.
The gaseous photolysis of 2-picoline N-oxide was also carried out by irradiating it with the 3261 or 2537 A resonance line. It was found that 2-picoline N-oxide undergoes a photochemical rearrangement to isomerize to 2-pyridinemethanol at 3261 A (n—π* transition) and a fission of N→O bond to produce 2-picoline at 2537 A (π—π* transition).
Thermal Isomerization of Isopropyl-1,1,1-d3 Radicals
Authors: Jackson W. M. , McNesby J. R. 
Published: January 2005

The unimolecular isomerization of isopropyl radicals was investigated by studying the thermal decomposition of pure CD3CH2CH3 from 472° to 553°C. Isomerization of CD3CHCH3, was detected by measuring CD2CHD formed from the isomerized radical. The net result of isomerization is reaction (14). (14)CH3CHCH3→[CH3CH2CH2]→C2H4+CH3,(15)CH3CHCH3→CH3CH=CH2+H.
It is found that isomerization of isopropyl up to 500°C proceeds at a rate, relative to decomposition via reaction (15), which can be described by k14/k15≤0.07. A mechanism which produces methyl and ethylene directly without intermediate isomerization gives k14/k15≤0.04 at 500°C. Contrary to other published estimates of k14/k15, the latter shows no downward trend with increasing temperature.
Hydrostatics in Various Gravitational Fields
Authors: Li Ta 
Published: January 2005

A closed axisymmetric container placed in a gravitational field is partially filled with a liquid. The stable configuration of the liquid—vapor interface is determined by minimizing the sum of the potential energy and the surface energies.
It is found that the Dupré—Young equation is an immediate consequence of the terminal condition of an isoperimetric problem, and that it is valid in all gravitational fields. Because of this fact, the initial radius of curvature of the liquid—vapor interface and the initial value of this interface which appeared as parameters in the solutions of the capillary equation of Gauss—Laplace—Young, derived from the isoperimetric problem, are expressed as functions of the radius of intersection of the interfaces.
The radius of the intersection of the liquid—vapor interface and the vapor—solid interface is evaluated by considering the vapor-to-tank volume ratio. Thus, the stable configuration is unique, once the form of the container, the contact angle, the volume ratio, and the gravitational field are given.
ESR Study of Thio-indigo and Related Free Radicals
Authors: Bruin M. , Bruin F. , Heineken F. W. 
Published: January 2005

Thio-indigo and various Cl, Br, CH3, OCH3, OC2H5, and C6H5 derivatives were converted into free radicals. The electron spin resonance of these radicals in acetone was studied under low and high resolution. The width at maximum slope of the unresolved spectrum is about 6 G. The spectra, consisting of hfs lines of 0.07–0.2 G width at a spacing of 0.1–0.4 G, could be consistently analyzed.
The relative unpaired-electron spin-density distribution in this type of molecule was determined. Cl and Br substituents do not give rise to observable splittings. Hyperconjugation appears to be effective for methyl substituents. For methoxy, ethoxy, and phenyl substituents a splitting due to the protons of these groups was found. The effect of substitution on observable electron spin densities is discussed.
Kinetics of Disappearance of Radicals Trapped in Irradiated Polyethylene
Authors: Smith W. V. , Jacobs B. E. 
Published: January 2005

Development of a technique for determining the concentration of alkyl radicals trapped in irradiated polyethylene using radio-iodine is described. It is applied to study the kinetics of alkyl radical disappearance in irradiated polyethylene and polypropylene, and the kinetics are interpreted in terms of a simple model.
The radicals are assumed to be formed in isolated spherical spurs and rapidly attain an approximately uniform concentration within a spur. This concentration decreases with time due to second-order recombination accompanied by a diffusion-like expansion of the spur.
Recombination is increased by hydrogen and the diffusive expansion is increased by hydrogen and by preirradiation. Both processes are faster in polypropylene than in polyethylene. The number of free radicals per spur after the irradiation decreases with increase in radiation dose due probably to the effect of the hydrogen produced by irradiation.
Valence-Bond Studies of the Dependence upon Substituents of C13–H and Si29–H Coupling
Authors: Juan Cynthia , Gutowsky H. S. 
Published: January 2005

An interpretation is presented for the additivity of substituent effects on the C13–H coupling constant, which has been observed previously in the high-resolution NMR spectra of substituted methanes. Each atom or group X is assigned a characteristic ``affinity'' for s character in the carbon hybrid orbital of the C—X bond. Distribution of s character among the carbon orbitals in accord with the relative s affinities of the four substituents leads to the observed additivity relation provided that the total s character is conserved. The valence-bond approach used with this model gives a linear relation between the s character of the carbon hybrid orbital involved in the C–H bond (αH2) and the observed C13–H coupling constant (JCH=500 αH2). Also, it allows the determination of the s character of the other carbon orbitals. The dependence of the s character of the C—X bond on the electronegativity of X is discussed in terms of electron spin and charge correlation. It is noted that the hybridization changes should affect not only JCH but also JHH, which is consistent with the observed proportionality between JCH(CH3X) and the cis and trans H–H coupling constants in CH2=C13HX.
The treatment developed for methanes has been extended to JCH in substituted ethylenes and to the Si29–H coupling in silanes. For the former, introduction of the s-electron affinities, obtained from the values of JCH(CH3X) observed for the substituted methanes, leads to the result that JCH(CH2=C13HX) = JCH(CH2=CH2)+43 [JCH(CH3 X) – JCH(CH4)]. Values predicted in this manner are systematically larger than those observed, which implies that there is a small, negative π-electron contribution of 5 to 10 cps to JCH(CH2=C13HX). Such a contribution is compatible with current theories for proton and C13 hyperfine splittings in ESR spectra of free radicals. The Si29–H coupling constants observed in substituted silanes exhibit large, systematic deviations from the simple additivity found in the methanes. These deviations are explicable qualitatively in terms of changes in the Si–H-bond polarity.
Interactions between Ordinary Vibrations and Hindered Internal Rotation. I. Rotational Energies
Authors: Kirtman Bernard 
Published: January 2005

The effect of vibration-hindered rotation interactions on the rotational energy levels of molecules containing a symmetric internal rotor has been re-examined theoretically. The complete Hamiltonian has been derived and includes terms which are due to Coriolis coupling and to the explicit dependence of the kinetic energy on the angle of internal rotation.
Over-all and internal rotation are separated from vibration, in zeroth order, by means of the Eckart and Sayvetz conditions. Difficulties in previous treatments are traced back to the application of these conditions. For each vibrational state, an approximate Hamiltonian for over-all and internal rotation is obtained by a Van Vleck perturbation treatment in which torsional denominators are assumed to be negligible. A correction for these denominators is determined by taking the first term in a power series expansion.
A preliminary transformation, similar to that described by Hecht and Dennison, is used to remove zeroth-order coupling between the angular momenta of over-all and internal rotation. Simple product wavefunctions, then, form a suitable basis for evaluating first-order energy corrections due to higher-order coupling of internal and over-all rotation.
Symmetric rotors, slightly asymmetric rotors, and asymmetric rotors with relatively high barriers to internal rotation are each treated separately. Empirical frequency expressions for rotational transitions of all three types of molecule are given. The symmetric rotor formula is identical in form to Kivelson's but the empirical constants must be interpreted differently. A symmetric rotor analysis was done on CH3SiF3 and CD3SiF3. K→K, J—1→J transitions of slightly asymmetric rotors obey a particularly simple frequency relation. Two groups of asymmetric rotor transitions are tractable: (1) The 00,0→10,1, ½[11,0→21,1+11,1→21,2], and 22,1→32,2 transitions, where the designation of levels is for a prolate rotor, and (2) transitions between the two members of an asymmetry doublet.
Reactions of Excited Butane Molecules
Authors: Beck D. , Niehaus A. 
Published: January 2005

To study the unimolecular reactions of highly excited molecules, a method for detection and analysis of the uncharged fragments has been reported. It uses excitation of the molecule by electron impact and—after about 10—5 sec—ionization and analysis of the fragments in a mass spectrometer.
This paper presents results for the butane molecule. The actually determined quantities are the relative concentrations of the uncharged fragments in the ion source. They are obtained with an average error of 20% and may be used to infer the relative probabilities (cross sections) of production from the molecule. The latter, constituting the neutral spectrum of the molecule, are compared quantitatively with the ion spectrum. A quantitative scheme for the decay of an excited butane molecule is set up and discussed. It is found that: (1) Radical production from the decay of the molecule occurs very seldom; (2) Excitation, high enough to be followed by break up, is about equally probable for ionized and neutral molecules.
For the radicals C3H5, C3H3, C2H5, CH3, CH2, and H, which originate from the decay of the molecule ion, the ionization potentials are reported.
Microwave Spectrum of Chlorine Dioxide. IV. Determination of Centrifugal Distortion Effects and Potential Constants
Authors: Pillai M. G. Krishna , Curl R. F. 
Published: January 2005

A reanalysis of the microwave spectrum of chlorine dioxide, taking into account the effects of centrifugal distortion, has been carried out. When the centrifugal distortion constants are forced to be consistent with the harmonic vibrational frequencies obtained from the visible spectrum, 18 rotational transitions of Cl35O2 are fitted with a standard deviation of 2.5 Mc.
The rotational and force constants obtained are A=52079.5±0.8 Mc, B=9952.23±0.15 Mc, C=8333.99±0.13 Mc, fd=7.0175±0.003×105 dyn cm—1, fα/d02=0.6514±0.002×105 dyn cm—1, fdα/d0=0.0064±0.0008×105 dyn cm—1 and fdd=—0.1699±0.003×105 dyn cm—1. The force constants were used to calculate the distortion shifts for the Cl37O2 molecule and the rigid-rotor frequencies for 7 rotational transitions of Cl37O2 were fitted with the rotational constants.
Sequential Filling of a Line by Intervals Placed at Random and Its Application to Linear Adsorption
Authors: Mackenzie J. K. 
Published: January 2005

A line with integral length n is filled sequentially at random with nonoverlapping intervals of integral length a, their end points having integer coordinates. It is shown that, as n tends to infinity, the average value of the length left vacant tends asymptotically to (n+a) A1(a) while its variance tends to (n+a) × aA2(a), where A1(a) and A2(a) are constants whose values are given numerically for all a; these asymptotic results are accurate to four significant figures for n/a&gt;8. Some results are also given for the (average) relative numbers of vacant spaces of length i=0, 1,..., a—1.
With certain restrictions, the above results can be applied to the complete adsorption of linear molecules which when once adsorbed remain fixed in position in the line troughs of suitable crystal surfaces such as (110) on an fcc crystal or (112) on a bcc crystal. These restrictions concern the way in which the molecule sits in equilibrium on the underlying crystal sur face.