bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distortion in the Metric of a Small Center of Gravitational Attraction due to its Proximity to a Very Large Mass
Authors: Manasse F. K. 
Published: January 2005

The problem of two bodies in general relativity in an especially restricted mode is analyzed. One body is of small mass, and, under the influence of gravitational attraction, moves toward a much larger mass whose field produces ``tidal'' deformations in the geometry of the smaller one. To evaluate these deformations, we treat the Schwarzschild metric of the particle by a perturbation analysis similar to that performed by Regge and Wheeler. The boundary conditions for this analysis are obtained from the metric of the background field expressed in a novel set of comoving coordinates, here called Fermi normal coordinates. These coordinates have been described in the previous paper. In this paper we use the Schwarzchild metric given there in comoving coordinates as an asymptotic approximation for the full solution which is evaluated here.
A perturbation analysis using the ``tidal deformation'' (background curvature) as an expansion parameter is performed on the metric of a small Schwarzschild particle. The solution so obtained satisfies Einstein's equations for empty space for small deviations from a nonflat metric. This solution also reduces to the Fermi metric in the appropriate limit, namely, when the ``distance'' from the geodesic is large compared to the radius of the small mass but small compared to the separation of the two masses. Thus only the quadratic terms in the distance are important. This solution is then used to find the deformations in shape of the throat of the wormhole and to locate this region of symmetry (the throat) by finding a coordinate transformation which leaves the metric invariant.
Principle of General Q Covariance
Authors: Finkelstein D. , Jauch J. M. , Schiminovich S. , Speiser D. 
Published: January 2005

In this paper the physical implications of quaternion quantum mechanics are further explored. In a quanternionic Hilbert space HQ, the lattice of subspaces has a symmetry group which is isomorphic to the group of all co-unitary transformations in HQ. In contrast to the complex space HC (ordinary Hilbert space), this group is connected, while for HC it consists of two disconnected pieces.
The subgroup of transformations in HQ which associates with every quaternion q of magnitude 1, the correspondence ψ → qψq−1 for all ψ∈HQ (called Q conjugations), is isomorphic to the three-dimensional rotation group. We postulate the principle of Q covariance: The physical laws are invariant under Q conjugations. The full significance of this postulate is brought to light in localizable systems where it can be generalized to the principle of general Q covariance: Physical laws are invariant under general Q conjugations. Under the latter we understand conjugation transformations which vary continuously from point to point.
The implementation of this principle forces us to construct a theory of parallel transport of quaternions. The notions of Q-covariant derivative and Q curvature are natural consequences thereof.
There is a further new structure built into the quaternionic frame through the equations of motion. These equations single out a purely imaginary quaternion η(x) which may be a continuous function of the space—time coordinates. It corresponds to the i in the Schrödinger equation of ordinary quantum mechanics. We consider η(x) as a fundamental field, much like the tensor gμν in the general theory of relativity. We give here a classical theory of this field by assuming the simplest invariant Lagrangian which can be constructed out of η and the covariant Q connection. It is shown that this theory describes three vector fields, two of them with mass and charge, and one massless and neutral. The latter is identifiable with the classical electromagnetic field.
Photoelastic Property of Cross-Linked Amorphous Polyethylene
Authors: Nagai Kazuo 
Published: January 2005

By assuming the additivity of bond polarizabilities, a formal expression is derived for the difference Δγ in principal polarizabilities of a real polymer chain having constant end-to-end distance r. The expression is given as a series in powers of r2, whose coefficients are functions of the differences α1κ—α2κ in principal polarizabilities of constituent bonds, 〈r2k〉, and 〈r2k cos2Φiκ〉, (k≥1). Here, Φiκ is the angle between the end-to-end vector and the unit vector along the κth bond of the ith structural unit, and the averages refer to those about a polymer chain in free state. It is shown that if r2 is in magnitude of the same order as 〈r2〉, at the limit of infinite chain length the expression reduces to Δγ=310〈r2〉*−2 ∑ i,κ(α1κ−α2κ)(3〈r2cosΦiκ〉−〈r2〉)r2,where 〈r2〉* is such a part of 〈r2〉 as proportional to chain length.
The difference in principal polarizabilities of the ``equivalent random link'' is shown to be ΔΓ=12〈r2〉*−1 ∑ i,κ(α1κ−α2κ)(3〈r2cos2Φiκ〉−〈r2〉).An expression in a matrix form is derived for ΔΓ of the polyethylene chain. Numerical computations are made by a digital computer, using two geometrical models for this molecule recently proposed by Hoeve and by Nagai and Ishikawa, and also using Denbigh's and Bunn and Daubeny's values for bond polarizabilities. It is found that a good agreement is obtained between predictions of the theory and experimental values if Denbigh's values are used.
Kinetics of Diffusion-Controlled Processes in Liquids. Theoretical Consideration of Luminescent Systems: Quenching and Excitation Transfer in Collision
Authors: Yguerabide Juan , Dillon Michael A. , Burton Milton 
Published: January 2005

The over-all behavior of reacting particles in solution is determined both by specific molecular properties and by probability of encounter. This paper presents an examination of the effect of the details of diffusion and locally inhomogeneous distributions on the over-all behavior of a system of reacting particles both for steady-state conditions and for the decay (or relaxation) phenomena subsequent to creation of an initial condition.
The problem is formulated for the quenching of excited molecules in solution in terms of diffusion equations for excited and quencher molecules with appropriate initial and boundary conditions. The diffusion equations are solved for a completely determined, but otherwise arbitrary, initial distribution of quencher molecules around an excited molecule and two sets of boundary conditions: the so-called Smoluchowski and ``radiation'' boundary conditions. The resultant equations give, in their turn, expressions for decay of excited molecules for initial random distributions following instantaneous excitation and, by the use of superposition integrals, for initial distributions following any form of excitation. Explicit expressions for the rise and fall of excited molecule concentrations result. The techniques are extendable in principle to a variety of essentially different processes.
NMR Study of Rotational Barriers and Conformational Preferences. I. Cyclohexyl Fluoride
Authors: Bovey F. A. , Anderson E. W. , Hood F. P. , Kornegay R. L. 
Published: January 2005

The equatorial:axial ratio and rate of conformational isomerization of cyclohexyl fluoride has been measured by observation of the 19F resonance as a function of temperature (—87.6° to +29.5°) for a 25 vol.% solution in CCl3F. Rate information is readily obtained over a wide temperature range, since the equatorial and axial fluorines differ in chemical shift by 20.5 ppm; the equatorial and axial α protons differ in chemical shift by only 0.46 ppm.
Interpretation of the spectra in terms of isomerization rates is complicated by the following: (a) the equatorial and axial conformers are present in unequal proportions; (b) their ratio changes with temperature; and (c) 19F–H coupling produces fine structure and/or peak broadening. The general expression for spectral line shape resulting from exchange between two unequal, chemically shifted spin populations is plotted (using the IBM 7090 computer), chemical shift and conformer ratio data being obtained from the low temperature 19F spectra. The observed spectra fit the calculated spectra very closely, and can be used with their aid to obtain the rates for axial-to-equatorial and equatorial-to-axial isomerization. Excess line broadening resulting from 19F–1H coupling was eliminated by double resonance.
Modifications to the rate expressions arising from the differing entropies and enthalpies of the axial and equatorial conformers are presented. Theoretical expectations for the activation entropies and enthalpies are discussed and compared to observed values.
Partial Pressures in Equilibrium with Group IV Tellurides. I. Optical Absorption Method and Results for PbTe
Authors: Brebrick R. F. , Strauss A. J. 
Published: January 2005

An optical-absorption method has been developed for measuring the partial pressures of Te2(g) and MTe(g) in equilibrium with MTe(c), where M is Pb, Sn, or Ge. The partial optical densities of Te2(g) at 4360 Å and of MTe(g) at 3650 or 3100 Å are obtained by a Beer's-law analysis of the data, which use optical constants for Te2(g) and MTe(g) found in calibration experiments. Published vapor-pressure data are then used to calculate the partial pressures of Te2(g) and MTe(g) from their respective partial optical densities.
This paper reports results obtained by the optical absorption method for the Pb–Te system. Between 725° and 924°C, the maximum melting point of PbTe, the partial pressure of PbTe(g) in equilibrium with solid PbTe is given by logp(Torr) = —11,430/T°K+10.612, corresponding to a heat of sublimation of 52.3±1.0 kcal/mole. The PbTe(g) partial pressure is independent of the composition of PbTe(c) within the limits of experimental error. The partial pressure of Te2(g) varies strongly with the composition of the solid phase, as shown by data for Pb-saturated and Te-saturated PbTe. The maximum partial pressure of Te2(g) in equilibrium with PbTe(c) is 12.5 Torr, which is attained between 796° and 832°C for Te-saturated PbTe. At these temperatures the partial pressures of Te2(g) in equilibrium with Pb-saturated Te are about two orders of magnitude smaller. The partial pressures of PbTe(g) and Te2(g) in equilibrium with PbTe(c) at its maximum melting point are 11.8 and 2.5 Torr, respectively.
Electron Spin Resonance Study of the Pairing Theorem for Alternant Hydrocarbons : 13C Splittings in the Anthracene Positive and Negative Ions
Authors: Bolton James R. , Fraenkel George K. 
Published: January 2005

The pairing theorem for alternant hydrocarbons predicts that the pi-electron spin densities at corresponding positions of the negative and positive ions of a hydrocarbon should be the same, but significant differences have been found previously for the proton hyperfine splittings in electron-spin resonance spectra. In order to examine the validity of the theorem more thoroughly, we have measured the 13C splittings in the ESR spectra of the anthracene negative and positive ions. These have been obtained by studying the satellites arising from 13C nuclei present in natural abundance and also by investigating anthracene labeled with 50% 13C in the 9-position. All of the four possible splittings were determined for the negative ion and assigned to the appropriate positions in the radical, and three of the splittings were obtained for the positive ion. The assignments of the splittings, and also their signs, were established by linewidth studies, counter-ion effects, and calculation. The negative ions were produced by reduction with lithium, sodium, and potassium, and also electrolytically. An apparatus for the electrolytic generation of radicals in vacuo is described. The positive ions were formed in concentrated sulfuric acid.
The 13C splittings in the positive and negative ions of anthracene were found to be almost identical. This result is most readily interpreted as implying that the pairing theorem is valid to a high degree of approximation for the spin densities and for those of the sigma—pi parameters (Q's) which govern the 13C splittings.
Forbidden Absorption-Band Systems of N2 in the Vacuum-Ultraviolet Region
Authors: Tanaka Y. , Ogawa M. , Jursa A. S. 
Published: January 2005

Five systems of absorption bands of N2, whose upper states are a 1IIg, a′ 1Σu—, B′ 3Σu—, w 1Δu, and C 3IIu, were investigated in the 1070–1600-Å region. A 2-m and a 3-m vacuum spectrograph, both of normal-incidence-type, were used in this work. The observations were extended to high vibration levels for four of the systems, a(v=13), a′(v=15), B′(v=20), w(v=11), while in the C—X system only two bands were analyzed. The progression which was previously ascribed as belonging to the w—X system was studied in detail, and an alternate possibility of this progression being the v″=1 progression of the a—X system was definitely removed. However, a final designation of the upper electronic state must come from a rotational analysis, because the observed T00 of the state differed from that of the w state by approximately 40 cm—1.
The potential energy curves of the low-lying N2 states prepared by Mulliken are compared with those calculated by using the presently determined constants.
Absolute Infrared Intensities of the Fundamental Absorption Bands in Solid CS2
Authors: Yamada Haruka , Person Willis B. 
Published: January 2005

Absolute infrared intensities have been measured for ν2 and ν3 of CS2 in the solid phase. Path lengths were measured by counting interference fringes as the solid is condensed onto a cold window. The index of refraction of the solid film is estimated from the intensity of the fringe pattern on different windows of known index of refraction. The problem of choosing a suitable background is discussed. Although two different kinds of films were formed, the intensities were identical within experimental error. The intensities found for ν2 and ν3 were 850±100 and 80 000±14 000 darks, respectively. These values are quite comparable to the intensities found in liquid CS2, and are both higher than found in the gas phase. Hence, the intensity sum rule does not hold for this crystal. The observed intensification is compared with that predicted from the simple field effect, using an elliptical cavity, and found to agree quite well. Hence, we conclude that CS2 molecules do not interact strongly in the crystal in ways which affect the intensity. The ``ideal'' behavior is tested further in a comparison of the observed frequency shift with that calculated from the Kirkwood—Bauer—Magat theory; again the agreement is quite good for ν3 where the predicted shift is large. For ν2, with a smaller predicted shift, the agreement is poor, indicating that other forces are at least as large.
Finally, the infrared spectra and x-ray powder pattern are used in combination to estimate the crystal structure. Both are consistent with an orthorhombic space group D2h12, with two molecules per unit cell (a=5.45, b=8.16, and c=3.74 Å). Although this space group is not determined uniquely, the crystal splitting was calculated from the dipole—dipole model, assuming that the structure was approximately correct in locating the molecules. The calculated splitting for ν3, where it is large, agrees very well with the observed splitting; for ν2, where the calculated dipole—dipole splitting is small, the agreement with experiment is poor.
Influence of Hydrodynamic Interaction on the Viscoelastic Behavior of Dilute Polymer Solutions in Good Solvents
Authors: Tschoegl N. W. 
Published: January 2005

The treatment by Ptitsyn and Eizner of the dynamics of dilute polymer solutions for dominant hydrodynamic interaction, taking into account excluded volume effects, is extended to the general case for changing hydrodynamic interaction. The function Φ (h, ε) is tabulated for selected values of ε, the parameter which accounts for the expansion of the coil due to excluded volume effects.
An approximate derivation of the storage and loss moduli from this theory is proposed. According to this calculation, an increase in ε causes a shift of the frequency dependence of the moduli from Zimm-like toward Rouse-like behavior. The determination of ε from experimental data is discussed.
Effect of Molecular Shape on Nuclear Magnetic Relaxation. II. Quadrupole Relaxation
Authors: Shimizu Hiroshi 
Published: January 2005

The dependence of quadrupole relaxation in NMR upon molecular shape is examined by regarding the molecule as a rigid ellipsoidal body which shows anisotropic rotational Brownian motions. Dependence of relaxation times upon the angle between the direction of the maximum field gradient and that of the molecular axis is considered also; the complex angular dependence of the relaxation times is derived, which suggests that careful examinations must be taken when we use the information on molecular motion from the other measurements. For example, the effective correlation time obtained from the quadrupole relaxation cannot be used directly to compute the proton relaxation times in an accurate precision.
The use of the ordinary theory of anisotropic Brownian motion in molecular system is examined, where the constituents of the ``liquid'' have comparable dimension with that of the solute molecule and they are by no means ``homogeneous.'' The improved theory is applied to the quadrupole relaxation in the system of axial ratio=2, which predicts that the spectral density is about 2∼8 times larger than the one given by the Debye—Bloembergen—Perrin—Favro theory.
Radiolysis of Simple Aromatics in Boric Acid Glass
Authors: Hughes Floyd , Kirk Russell D. , Patten Frank W. 
Published: January 2005

Electron paramagnetic resonance studies have been made of the stable free radicals produced by x irradiation of aromatic hydrocarbons dissolved in partially dehydrated boric acid glass. In general, singly charged molecular ions were not found to be the sole species.
Deuterium substitution in the boric acid glass showed that all end point radicals contained hydrogen from the matrix. All glasses exhibited a 100–140 G EPR pattern, which has been interpreted as that of radicals produced by formation of a —CH2— group in a benzene ring.
Electron Spin Resonance Studies of Irradiated Single Crystals of Creatinine and Creatine
Authors: Ueda Hisashi 
Published: January 2005

The electron spin resonance spectra of x-irradiated single crystals of creatinine: creatinine HX (X=HO2, F, Cl, Br, I, and NO3): Ca creatine, and creatine phosphate, have been studied at room temperature. The ESR spectrum of an x-irradiated single crystal of creatinine at 77°K has also been studied. The free radicals formed in these compounds have similar structures to those formed in irradiated N-acetylglycine, glycylglycine, and diketopiperazine. The unpaired electron spin density distribution was computed by a Hückel molecular orbital method using an electronic computer, and was compared with the experimental results.
The anisotropic components of the observed splitting factors were relatively smaller in these compounds than those found in N-acetylglycine, glycylglycine, diketopiperazine, and malonic acid. This can be explained by considering the effective nuclear charge on the vicinal nitrogen atom which will affect the s character of the unpaired electron on the carbon atom, where the electron has main spin density of some 0.5.
The free radical, first formed, has a structure in which the unpaired electron is localized on three atoms. This, then, transforms to a delocalized species with a larger conjugated system. The delocalization energy for this transformation is about 8.3 kcal/mole.
Microwave Spectrum, Molecular Structure, and Quadrupole Coupling Constants of 2-Chloropropane
Authors: Tobiason F. L. , Schwendeman R. H. 
Published: January 2005

The microwave spectra of (CH3)2CHCl35, (CH3)2CHCl37, (CH3)2CDCl35, (CH3)2C13HCl35, C13H3CHCl35CH3, CH2DCl35CH3 (3 species), and CD3CDCl35CH3 have been examined and a complete structure has been obtained by the substitution method. The parameters obtained are as follows: r(CC) = 1.522 Å, r(CCl) = 1.798 Å, r(CHsec) = 1.091 Å, r(CHmethyl) = 1.092 Å, ∠CCC = 112.7°, ∠CCCl = 109.4°, ∠CCHsec = 109.9°, ∠CCHα = 110.9°, ∠CCHβ,γ = 109.7°.
The quadrupole coupling constants in the principal axis system of (CH3)2CHCl35 have been determined to be χaa = —61.49 Mc/sec, χbb = 34.81 Mc/sec, and χcc = 26.68 Mc/sec. These values are consistent with χzz = —69.61 Mc/sec assuming a cylindrical charge distribution near the Cl nucleus, or with χzz = —67.82 Mc/sec and η = 0.0275 assuming that the z axis and the CCl internuclear line coincide.
From the absence of observable splitting in certain high J transitions in CD3CDCl35CH3, it has been concluded that the potential barrier hindering internal rotation of the methyl groups is greater than 3450 cal/mole.
Polarized Emission and Triplet—Triplet Absorption Spectra of Aromatic Hydrocarbons in Benzophenone Crystals
Authors: Hochstrasser Robin M. , Lower Stephen K. 
Published: January 2005

The polarization of the phosphorescence of naphthalene, anthracene, pyrene, and chrysene as guest in the benzophenone lattice have been examined. Considerable out-of-plane intensity has been shown to be present in these transitions. The results have confirmed conclusions from previous experimental observations and have led to certain assignments for the lowest triplet states which are in agreement with theoretical predictions.
The triplet—triplet absorption spectra of naphthalene, anthracene, and chrysene have been detected using polarized light and the mixed crystals. All these T—T transitions were polarized in the aromatic molecular planes, in accordance with theory.
The phosphorescence of pyrene in benzophenone has been analyzed and tentatively interpreted as triplet—singlet emission of the pyrene dimer.
Nuclear Magnetic Resonance Study of the Solvation of Co++ in Methanol and Methanol—Water Mixtures
Authors: Luz Z. , Meiboom S. 
Published: January 2005

Proton magnetic resonance spectra of solutions of Co(ClO4)2 in acidified methanol, and in methanol—water mixtures are reported. At temperatures below about —50°C separate peaks for the bulk methanol and for the methanol bonded to Co++ are observed, and methanol exchange is too slow to contribute appreciably to the observed linewidths. Peak intensity measurements give a coordination number of six for Co++ with respect to methanol. From the temperature dependence of the peak frequencies, values of the hyperfine interaction between the bonded methanol protons and the Co++ ion were obtained. The results are +8.8×105 cps for the OH protons and +3.9×105 cps for the CH3 protons. The linewidths are shown to be predominately determined by electron—proton dipole—dipole interaction. The relevant correlation time is the electron relaxation time, which is approximately 5×10—13 sec at —60°C. This time decreases with increasing temperature, with an apparent activation energy of 0.9 kcal mole—1.
In methanol—water solutions, additional lines, due to mixed methanol—water complexes of cobalt, are observed. Equilibrium constants for the formation of the mono- and dihydrated mixed complexes were obtained from measurements of peak intensity as function of water concentration.
At temperatures above about —50°C the rate constant of methanol exchange between complexes and bulk solvent was obtained from the excess widths of the peaks. Comparison of the OH and CH3 linewidths shows that whole methanol molecules exchange, i.e., proton exchange between the complexes and the solution is relatively unimportant.