bluuebunny/crossref_metadata_2025 huggingface dataset:
The Tensile Strength of Benzene
Authors: Donoghue J. J. , Vollrath R. E. , Gerjuoy E.
Published: January 2005

Measurements were made of the tensile strength of benzene, by the centrifuge method. The method is described, together with various features which have been incorporated into the procedure to insure uniformity of samples. There is evidence, which is not conclusive however, that the rupture strength increases as the amount of permanent gas dissolved in the liquid decreases. At any given permanent gas pressure in equilibrium with the liquid our results are highly variable. Although further confirmation is needed, it appears that the variability is a result of differing histories of our tubes and not of lack of uniformity of our benzene samples. Exposure of the glass surface to the atmosphere appears to decrease the tensile strength. Our highest observed rupture strength, 157 atmospheres, is believed to represent the adhesion strength of the benzene to the walls of a particular tube, and may be much less than the limiting tensile strength of benzene. No evidence for a temperature dependence of the tensile strength has been found, but this result is probably also not representative of the limiting tensile strength of benzene.
A Theory of Cooperative Phenomena. II. Equation of States for Classical Statistics
Authors: Kikuchi Ryoichi
Published: January 2005

A method of obtaining the equation of state of a classical assembly through the solid, liquid, and gas phases based on the order-disorder concept is explained. At first, the method is illustrated on an imaginary two-dimensional model. Next, the general procedure to increase the number of interstitial sublattices to infinity is explained for a one-, two-, and three-dimensional lattice. In the one-dimensional case, the present method proves to be identical with Gürsey's rigorous solution. An approximate treatment for the solid state is added.
Isotope Effect in the Band Spectrum of HNO2
Authors: Porter George
Published: January 2005

The band system between 3100 and 3900A which has been attributed both to HNO2 and enhanced NO2 is shown to belong to the former molecule by means of the isotope effect. Measurements of the spectrum of DNO2, and a partial interpretation of the band structure and isotope shift are given.
Scintillations in the Diphenylpolyenes and Related Compounds
Authors: Koski W. S. , Thomas C. O.
Published: January 2005

Scintillations in two series of structurally related organic compounds were investigated. One series was composed of the symmetrical diphenyl derivatives of ethane, ethylene, and acetylene. The other series consisted of the diphenyl polyenes from diphenyl to diphenyl octatetraene. In the first series it was found that the wavelength of the emission spectra ranged from 3550 to 4030A and the counting efficiency increased with the number of π-electrons in the system. In the second series the emission spectra wavelengths ranged from 3400A to 6000A and increased as one went up the series, whereas the counting efficiency went through a maximum at diphenyl butadiene. The results were interpreted in terms of the ``metallic'' model for conjugated compounds.
Molecular Quadrupole Moments of N2 and O2
Authors: Greenhow Charles , Smith William V.
Published: January 2005

Molecular orbital calculations of the quadrupole moments of N2 and O2 have been made. Models assuming 20 percent s—p hybridization for N2 and 5–10 percent s—p hybridization for O2 give calculated quadrupole moments agreeing with those deduced from microwave line broadening data (0.27e×10−16 esu for N2 and <0.09e×10−16 esu for O2).
The Ultraviolet Spectra of Benzene-Halogen Complexes and of Iodine in Solution
Authors: Ham J. S. , Platt J. R. , McConnell H.
Published: January 2005

The spectra of the 1:1 complexes between benzene and iodine and between benzene and bromine were examined in the wavelength range 2350–3500A using a 64-micron cell. In both cases a new absorption band was found at 2600A. This band is of considerable theoretical interest in connection with previous discussions of the spectra and structures of the benzene-halogen complexes. Also, the solution spectrum of iodine has been extended to 1820A and the f value compared with predictions.
The Cataphoresis of Spherical Fluid Droplets in Electrolytes
Authors: Booth F.
Published: January 2005

A theory of the electrophoresis of spherical fluid droplets in an electrolyte is developed. A general formula is given for the electrophoretic velocity in terms of the applied field, the potential distribution in and near the drops, and the dielectric constants and coefficients of viscosity of the liquid and electrolyte. It is assumed that the liquid drop retains its spherical form in cataphoresis and also that relaxation effects in the electrolyte may be neglected.

Detailed formulas are worked out for the case of a Debye-Hückel potential in the electrolyte, and the following charge distributions in the fluid sphere.

(a) No charge within the sphere; the whole charge is concentrated on the interface.

(b) Uniform volume distribution of charge.

(c) Ionic double layer potential in the sphere.

It is shown that sundry special cases of the theory agree with previous computations and that it is not legitimate to apply theories of the cataphoresis of solid particles to fluid drops.
Elastic Relaxation and Structure of Liquids. I. Ultrasonic Absorption in Some Halogenated Methylenes, Ethanes, and Ethylenes
Authors: Sette Daniele
Published: January 2005

In order to obtain information on the presence of structural effects in the elastic relaxation phenomena observed in liquids, the ultrasonic absorption was studied as a function of temperature in some organic compounds whose structure is correlated in a simple way. Large differences of absorption coefficient and of its temperature dependence have been found. It is difficult, at the present time, to understand clearly the results, but they show that the liquid structure has a great importance in the relaxation phenomena present in liquids.

Moreover an increase in dipole moment of the molecules is often present with an increase of absorption, showing that the dipole moment is not related in a simple way with the characteristics of relaxation phenomena and that all the interactions among the molecules are to be taken in account.
On the Elastic Relaxation in Carbon Disulfide: The Temperature Dependence of the Ultrasonic Absorption Coefficient
Authors: Sette Daniele
Published: January 2005

The experimental values of the ultrasonic absorption coefficient given in the literature for carbon disulfide show the presence of dispersion in the frequency range 1–100 Mc/sec, but large differences are present in the values obtained by various authors at the same frequencies so that it is difficult to analyze the behavior of this liquid. In order to discriminate among the various results more information is needed. For this reason a measurement of the absorption coefficient was performed at 30 Mc/sec. The value obtained for α is in agreement with the higher values of the absorption coefficient obtained by other authors at various frequencies and, therefore, it gives more credence to them in comparison with others.

The absorption coefficient as a function of temperature does not follow a linear law as it does in other unassociated liquids. The temperature coefficient (1/α)(∂α/∂t) goes from 7.3·10−3 deg−1 at −23°C to almost zero near the boiling point. These results can be used to examine the theoretical explanations of absorption in carbon disulfide based on the assumption that all the vibrational modes relax together or on the hypothesis that they have different relaxation times. The value of the temperature coefficient at 25°C seems to be better explained with the first treatment.
Vapor Pressures below 1 mm Hg of Several Aromatic Compounds
Authors: Hopke E. R. , Sears G. W.
Published: January 2005

Vapor pressures of the three isomeric picolines and p-di-tert-butylbenzene were determined over a pressure region of approximately 5–250 microns Hg using a Rodebush manometer and an effusion manometer for each compound. The experimental results of the two methods show good agreement. A comparison of the two manometers is made and the merits of each method are discussed.
Quantitative Line-Width Measurements in the Infrared. II. Unpressurized Carbon Monoxide
Authors: Penner S. S. , Weber D.
Published: January 2005

Experimental measurements on self-broadening of CO are correlated quantitatively by the use of a dispersion formula for line-shape representation. Interpretation of experimental data in terms of a simplified line-intensity distribution leads to the conclusion that the apparent rotational half-width of CO changes with the pressure of CO at approximately the same rate as with the pressure of H2 for the fundamental. Similar calculations for the first overtone lead to relatively small values for the apparent rotational half-width. Numerical calculations for a realistic line-intensity distribution have not been carried out.
I. Normal Frequencies of a One-Dimensional Crystal. II. An Approximation to the Lattice Frequency Distribution in Isotropic Solids
Authors: Halford J. O.
Published: January 2005

I. The accurate expression for the individual frequencies of a linear crystal of any number of particles is derived.

II. It is shown that, for an isotropic three-dimensional array of uniform masses, the root-mean-square frequency is easily evaluated and the maximum square must always be less, but not much less, than twice the mean square. For two commonly studied simple cubic systems, the maximum square is evaluated and shown to be twice the mean square. The Debye expression for the frequencies in terms of standing wave components is modified empirically to give the correct maximum and mean squares by substituting linear crystal frequencies for the components and introducing a second force constant.

The resulting expression, a simplified form of the factored secular equation, should yield a more realistic and probably therefore a more widely useful distribution function than the Debye equation.
A Note on the Quantum-Mechanical Perturbation Theory
Authors: Löwdin Per-Olov
Published: January 2005

The solution of the quantum-mechanical eigenvalue problem is discussed for cases when a series of approximate eigenfunctions is known. If these ``unperturbed'' states are divided into two classes, a perturbation formula is derived giving the influence of one class of states on the other in the final solution. The formula contains as special cases: (i) the Schrödinger-Brillouin formula for the eigenvalue of a nondegenerate state, (ii) a new simple formula for treating a class of degenerate states, and (iii) the splitting of the secular equation in cases where the system naturally consists of two independent parts in mutual interaction.
Excluded Volume Effect in Polymer Chains. I
Authors: Frisch H. L. , Collins F. C. , Friedman B.
Published: January 2005

The number of allowed configurations of a polymer chain is considered on the basis of a random walk on an arbitrary ``regular'' lattice. Upper and lower bounds for the number of nonoverlapping configurations in various lattices have been derived by means of a recursion formula method. The probability density function and its moments for the ``head-to-tail'' distance for short-range nonoverlapping chains are shown to the calculable by the use of a generating function. The order of the logarithm of the number of nonsuperposable ring polymer chains has been shown to be directly proportional to the number of segments composing the ring.
The Dielectric Constant of Ethylene at High Pressures
Authors: David H. G. , Hamann S. D. , Pearse J. F.
Published: January 2005

The dielectric constant of ethylene has been measured at pressures up to 500 atmospheres and at temperatures of 25°C and 50°C. At both temperatures the Clausius-Mosotti function has been found to pass through a maximum with increasing density. The results have been discussed with reference to Kirkwood's theory of dielectric polarization.
Statistical Theory of Rubber-Like Elasticity. IV. (Two-Dimensional Stretching)
Authors: Isihara Akira , Hashitsume Natsuki , Tatibana Masao
Published: January 2005

The failure, revealed by the experiment of Treloar, of statistical theories of the rubber-like elasticity is removed. It comes from the neglection of the nongaussian character and of the nonlinear connectivity of the network structure. The theoretical formula derived here includes the semi-empirical formula given by Treloar.
Heat Generation by Electric Sparks and Rate of Heat Loss to the Spark Electrodes
Authors: Roth Walter , Guest P. G. , von Elbe Guenther , Lewis Bernard
Published: January 2005

In a capacitance spark the gas between the electrodes is heated almost instantaneously; subsequently, the spark-generated heat flows from the gas to the material of the electrodes. In the present experiments sparks of 0.1 to 2 millijoules were passed between Pt electrodes in a bulb containing helium or argon or xenon, and either the pressure change, Δp, at constant volume v or the volume change, Δv, at constant pressure p was recorded, the former by means of a sensitive diaphragm and the latter by the movement of a droplet in a capillary tube attached to the bulb. The spark-generated heat H residing in the gas at any instant was computed from the equations H=1.5vΔp and H=2.5pΔv, which apply to constant volume and pressure, respectively, and are derived from the gas law and the energy equation, using the heat capacity of monoatomic gases. From the values of H and the discharge energy corresponding to the measured capacitance and breakdown voltage, the percentage of spark-generated heat residing in the gas was obtained. Immediately after discharge the percentage was found to exceed 95. The rate at which the percentage decreases with time was found to be independent of total energy and vessel diameter above a critical value of the latter. It was found to become smaller with decreasing heat conductivity of the gas, decreasing diameter of the spherical electrodes, and increasing gap length, as expected on the basis of heat loss from the gas to the electrodes. With electrode diameters of 1 mm, the heat loss after about 30 milliseconds ranged from a few percent for xenon and 10 mm gap length to 75 percent for helium and 1 mm gap length. An increase of the electrode diameter to 3 and 4.6 mm caused a substantial increase of the rate of heat loss; for example, for xenon and 10 mm gap length the heat loss after about 30 milliseconds was 28 percent and 35 percent, respectively. It was found that for constant electrode diameter the data for the several gases and gap lengths could be combined in a plot of percentage heat loss against a dimensionless parameter, θ, representing the product of thermal diffusivity and time elapsed since discharge, divided by the square of the gap length. By means of the latter parameter, one may estimate an upper bound of the heat loss during the formation of a combustion wave from a spark in an explosive gas, i.e., during the process of spark ignition, on the basis that the combustion wave is formed in a time interval smaller than the time required for the wave to travel a distance equal to its width. It is found that the loss of spark energy during the ignition process is always rather small.
On the Quantum-Mechanical Calculation of the Cohesive Energy of Molecules and Crystals. Part I. A General Energy Formula for the Ground State
Authors: Löwdin Per-Olov
Published: January 2005

A simple expression for the energy of the ground state of a molecule or a crystal is derived by starting from a total wave function, which is a Slater determinant of molecular spin orbitals or Bloch spin orbitals, formed by linear combinations of atomic orbitals. By the introduction of the new idea of ``combined atomic orbitals,'' the energy is expressed only in terms of two-center integrals of atomic orbitals, but the formula still includes the bonding and the overlapping between neighbors of all orders, and further, all the three-center and four-center integrals occurring in previous formulas. A simplified expression of the cohesive energy is given for the case the given atomic orbitals belong to the self-consistent field with exchange of the free atoms.
The Infrared Dispersion of Acetylene and the Dipole Moment of the C–H Bond
Authors: Kelly R. L. , Rollefson R. , Schurin B. S.
Published: January 2005

The index of refraction of acetylene has been measured at 55 wavelengths in the infrared between 1 and 20 microns. The contributions of the molecular vibrations to the index of refraction have been determined and interpreted in terms of effective charges on the constituent atoms. According to the analysis, during the infrared-active bending vibration the hydrogen atoms have an effective charge of 0.991×10−10 esu. The product of this effective charge by the separation of the carbon and hydrogen atoms is interpreted as giving an estimate of the C–H bond moment, the value obtained being (1.05±0.01)×10−18 esu cm. For the active stretching vibration, the computed effective charge was 0.515×10−10 esu, which is the rate of change of bond moment with internuclear distance. A comparison of these results with previous work indicates a possible regularity in the C–H bond moment in going from methane to ethylene to acetylene, although the regularity may be only apparent.
The Infrared Spectrum and the Structure of Gaseous Nitrous Acid
Authors: Jones Llewellyn H. , Badger Richard M. , Moore Gordon E.
Published: January 2005

An investigation of the infrared spectrum of nitrous acid has shown that in the gaseous state this substance exists in two tautomeric species which are believed to be trans- and cis-forms. The cis-form is of higher energy by about 506 calories mole−1. A complete vibrational analysis is given and the OH in plane bending frequencies are found to be 1260 cm−1 and ∼1292 cm−1, and the out of plane frequencies 543 cm−1 and 637 cm−1 for the trans- and cis-molecules, respectively. From the rotational constants the O–N–O angle is estimated to be 118° for the trans-form and 114° for the cis-form, from which conclusions are drawn regarding the electronic structure of the molecule. The standard entropy of nitrous acid at 25° is calculated.
Vapor Phase Photolysis of Formaldehyde at Wavelength 3130A
Authors: Calvert J. G. , Steacie E. W. R.
Published: January 2005

The vapor phase photolysis of formaldehyde at wavelength 3130A has been investigated at high temperatures. The experimental results indicate that the rate of hydrogen formation is directly proportional to the first power of the intensity of absorbed light, and at constant intensity of absorbed light the rate is accelerated by the addition of formaldehyde or inert gas with about equal efficiency. Propylene and nitric oxide inhibit the rate. The mechanism of the photo-decomposition is suggested to be: H2CO+hν=HCO+HH+H2CO=H2+HCO  E≦5 kcalHCO=H+CO     E≧13 kcalHCO+(Wall)=Products+(Wall).
The Infrared and Raman Spectra of Condensed Nitric Oxide
Authors: Smith A. Lee , Keller William E. , Johnston Herrick L.
Published: January 2005

The infrared and Raman spectra of liquid and solid nitric oxide have been studied in an attempt to prove the existence of the (NO)2 molecule. The liquid has four strong Raman lines at 1861, 262, 196, and 167 cm−1; two weaker Raman lines at 1760 and 487 cm−1; and two strong infrared bands at 1863 and 1770 cm−1. Several weaker infrared bands can be satisfactorily assigned as combinations by using the observed strong infrared and Raman frequencies. The spectra were found to be due exclusively to a dimer which probably exists as a bent ONNO molecule.
An Averaged Field Calculation of the Polarity of the Carbon-Hydrogen Bond
Authors: Mueller Charles R. , Eyring Henry
Published: January 2005

Considering the carbon-hydrogen bond as an isolated unit, and including the effect of the interelectronic repulsions, a quantum-mechanical calculation of the polarity of this bond is made. The bond dipole is found to be C+H−. On the basis of these calculations, the effect of change in hybridization on the C–H dipole, and the similar effect of replacement of hydrogen in a hydrocarbon by a highly electronegative substituent, is qualitatively discussed. It is predicted that, in both cases, there will be a tendency for the dipole moment to reverse itself.
The Effect of Pressure on the Melting of Several Methyl Siloxanes
Authors: Bridgman P. W.
Published: January 2005

Previous experiments had left open the possibility that the melting phenomena of the methyl siloxanes might be an exception to the universal behavior of all other known substances, namely, that there is no experimental evidence for a critical point between solid and liquid or for a maximum or temperature asymptote on the melting curve. The special apparatus necessary for an examination of the siloxanes in this respect has been constructed, and it has been found that they do not constitute any exception. The abnormality of their melting behavior is sufficiently explained by abnormal subcooling effects connected with the abnormally large increase of viscosity of these substances under pressure.
The Fluorescence of Acetone Vapor
Authors: Luckey G. W. , Noyes W. Albert
Published: January 2005

An apparatus has been designed and built for the study of low fluorescence intensities. The ``blue'' fluorescence of acetone vapor has been investigated from pressures of about 1 mm to pressures of about 200 mm, at temperatures from 25°C to 300°C both with and without the addition of foreign gases, such as O2, NO, N2, and (CH3CO)2.

It is found at temperatures over about 100°C, and in the presence of O2 and NO, that there is no structure in the fluorescence of acetone which can be detected, and the wavelength of the intensity maximum is different from that found at 25°C. The shapes of the quenching curves are such as to demand at least two upper electronic states which participate directly or indirectly in the fluorescence phenomenon. This is in agreement with previous work. The photo-chemical data necessitate a high probability of predissociation of the initially formed state together with a small lifetime probably determined by the rate of predissociation. At least one other upper state, formed from the first through collisions, must be relatively insensitive to collisional deactivation. A complete theory cannot be given, but some important aspects are clear.
Spectroscopic Moment: A Parameter of Substituent Groups Determining Aromatic Ultraviolet Intensities
Authors: Platt John R.
Published: January 2005

By the theory of Sklar and Förster, the added intensity produced in the benzene 2600A transition by monosubstitution is proportional to the square of a transition moment or ``spectroscopic moment'' induced by the substituent. The sign of the moment may be positive or negative. On disubstitution, para intensities are greater than meta and ortho if both signs are the same, less if they are opposite. The theory is used with available data to determine the relative spectroscopic moment for 25 different substituents. This moment is closely related to the ``mesomeric moment'' and to directing power, but the correlation is not perfect.

The theory is extended to account for intensity changes in the weak long-wavelength transitions (1A—1Lb) of derivatives of other cata-condensed ring systems, such as naphthalene, phenanthrene, 1,2-benzanthracene, etc. The increases of intensity produced by substituents, and their spectroscopic moments, appear to be almost identical with those found in benzene.
The Visco-Elastic Properties of Solutions of Rod-Like Macromolecules
Authors: Kirkwood John G. , Auer Peter L.
Published: January 2005

The general theory of irreversible processes in solutions of macromolecules is employed to investigate the visco-elastic behavior of solutions of rod-like macromolecules. It is found that rotatory diffusional torques are responsible for three-fourths of the stationary intrinsic viscosity. Under the action of periodic shear waves, the rotatory diffusional contribution to the stress exhibits relaxation phase lag and imparts a rigidity to the solution. As the frequency is increased, the intrinsic viscosity drops to one-fourth of its stationary value and the rigidity modulus increases to an asymptotic value of 3RT/5 per mole/cm3 of solute.
Exchange between N230 and N228 over Iron Catalysts
Authors: Kummer J. T. , Emmett P. H.
Published: January 2005

The rates of exchange between N228 and N230 obtained on doubly- and singly-promoted iron catalysts is of the right order to be accounted for by assuming that all nitrogen evaporating from the surface of the catalyst is completely equilibrated with respect to the nitrogen isotope exchange. Large concentrations of hydrogen (50 percent H2 in N2) markedly accelerate the reaction. Small traces of surface oxides poison the iron catalysts severely for the isotope exchange.
The Rotation-Vibration Spectrum of Methyl Cyanide in the Region 1.6μ—20μ
Authors: Venkateswarlu Putcha
Published: January 2005

The infrared spectra of gaseous and liquid CH3CN have been investigated in the region 1.6μ—20μ with a Perkin-Elmer spectrometer using LiF, NaCl, and KBr prisms. The parallel type bands show, in general, a sharp Q branch and broad but more intense P and R branches. The perpendicular type bands are well resolved and show the expected intensity alternation ``strong, weak, weak, strong . . .'' of the subbands (Q branches).

All the fundamentals, except ν8(e), which is beyond the region investigated, have been definitely established and vibrational assignments have been made for all the observed bands.

Values for the rotational constants from microwave data have been used to obtain the Coriolis interaction constants,ζi, from the observed separations of the subbands of the ⊥ bands. The following values have been obtained: ζ5=0.10, ζ6=−0.44, and ζ7=0.41.
The Infrared Spectrum of Methyl Chloroform in the Region 1.6μ—20μ
Authors: Venkateswarlu Putcha
Published: January 2005

The infrared spectrum of methyl chloroform has been investigated in the region 1.6μ—20μ with a Perkin-Elmer spectrometer using LiF, NaCl, and KBr prisms. Vibrational assignments are given to all the bands observed, and all fundamentals except the torsional vibration have been fairly definitely established. Most of the bands, whether perpendicular or parallel type, show the same kind of PQR structure.
The Mercury (3P1) Photo-Sensitized Decomposition of Propane at High Temperatures
Authors: Bywater S. , Steacie E. W. R.
Published: January 2005

The mercury (3P1) photo-sensitized decomposition of propane has been studied from room temperature to 450°C at pressures between 4 and 300 mm. The high temperature results are explained in terms of the decomposition of the propyl radical to form ethylene or propylene, and activation energies of 20 and 38 kilocalories, respectively, are assigned to these reactions. Experiments are also described where propane and propylene were in competition for hydrogen atoms, the relative rates of reaction being found at three temperatures. The difference in the activation energies of the two reactions is 4 kilocalories. The reactions at lower pressures are more complex and only a qualitative description of them can be given.
The Reactions of Methyl Radicals. IV. The Abstraction of Hydrogen Atoms from Cyclic Hydrocarbons, Butynes, Amines, Alcohols, Ethers, and Ammonia
Authors: Trotman-Dickenson A. F. , Steacie E. W. R.
Published: January 2005

The photolysis of acetone in the presence of various compounds has been investigated between 70°C and 340°C. If the reaction CH3+CH3=C2H6has no activation energy, then the activation energies in kcal for the reactions of the type CH3+RH=CH4+Rare cyclopropane 10.3, cyclobutane 9.3, cyclopentane 8.5, cyclohexane 8.3, benzene 9.2, toluene 8.3, 1-butyne 9.1, 2-butyne 8.6, methanol 8.2, ethanol 8.7, iso-propanol 7.3, methyl ether 9.5, iso-propyl ether 7.3, monomethyl amine 8.4, dimethyl amine 7.2, trimethyl amine 8.8, and ammonia 10.0. The collision theory steric factors are of the order of 10−3 or less for all these reactions.

A table is presented summarizing the results so far obtained on methyl radical reactions by the photolysis of acetone in the presence of other compounds. The accuracy of the method and some of the general implications of the results are discussed.
The Diffusion of Thoron Atoms through Photographic Gelatin
Authors: Eichholz G. G. , Flack F. C.
Published: January 2005

Observations have been carried out on the splitting of thorium stars in photographic emulsions. It is found that this process is caused entirely by the Brownian motion of the thoron atoms produced in the course of successive decays. Applying the classical statistical theory, the diffusion coefficient of thoron in gelatin and the viscosity of dry gelatin at room temperature have been deduced. The results are discussed in the light of our present knowledge of the structure of gelatin.
Theory of High Polymer Solutions (The Dumbbell Model)
Authors: Isihara A.
Published: January 2005

Following the theories of McMillan, Mayer, and Zimm, and extending the previous theories of the author, the second virial coefficient A2 for high polymer solutions of the dumbbell model is calculated. The results are rigorous within the approximation of rigid-body potential. A2 varies smoothly with l/R, where R is the radius of spheres of the dumbbell and l is their separation. Based on the present results, comparisons between the gas and the lattice theories are made.
Isotope Effect on Dissociation Probabilities in the Mass Spectra of Chloroform and Chloroform-d
Authors: Dibeler Vernon H. , Bernstein Richard B.
Published: January 2005

The mass spectra of the isotopic molecules CHCl3 and CDCl3 have been determined, using electron energies of 50 v and 70 v. It was found that the probability of dissociation of the C–H bond is approximately three times that for the dissociation of the C—D bond. The relative probability of dissociating H+Cl and D+Cl is the same as the relative probability of obtaining HCl+ and DCl+ ions, namely, about 1.6. Equal probability was observed for the dissociation of H+2Cl and D+2Cl. The probability of removing chlorine atoms is only slightly affected by the deuterium substitution.
The Crystal Structure of NaPt3O4
Authors: Waser Jürg , McClanahan Edwin D.
Published: January 2005

The structure of a microcrystalline platinum compound is derived from x-ray data. Space group Oh3—Pm3n, a0=5.69A, with 6 Pt at ±(¼ 0 ½, ↺), 8 O at ±(¼ ¼ ¼, ¼ ¾ ¾, ↺), and 2 Na at (000, ½ ½ ½), corresponding to the formula NaPt3O4. The coordinations are as follows: platinum 4 O and 2 Pt, oxygen: 3 O and 2 Na, sodium: 8 O. The substance is an ionic conductor.
Energy Transfer in the Photo-Sensitization of Silver Halide Photographic Emulsions: Optical Sensitization, Supersensitization, and Antisensitization
Authors: West W. , Carroll B. H.
Published: January 2005

Many facts concerning optical sensitization of silver halide photographic emulsions point to the importance in the sensitization process of the migration of excitation energy from a dye molecule primarily excited by radiation to neighboring molecules in a cooperative layer. Individual dye molecules, however, appear capable of transferring energy to the silver halide without the intervention of energy migration, often with high efficiency, as is shown by relatively high quantum yields of sensitization at low concentrations of dye. If, as a result of increase in the concentration of dye, the sharp absorption bands indicative of exciton migration appear, the efficiency of transfer tends, in fact, to fall. Dyes in the cooperative state, however, are most susceptible to the increase of sensitization caused by supersensitizers. The regular periodic field which favors exciton migration decreases the probability of energy transfer to the halide, and the supersensitizer appears to act as a perturbation of this field at which the moving exciton is slowed down so as to facilitate transfer. Consistent with this explanation is the high quenching power of supersensitizers on the fluorescence sometimes exhibited in solution and in the adsorbed state by cooperative aggregates of dye molecules. The inverse of supersensitization, antisensitization by relatively small amounts of nonplanar dyes, is also observed. Here the migrating energy in the cooperative layer is dissipated as heat by the perturbing molecule, and is prevented from reaching the silver halide. Experimental evidence supporting these conclusions is furnished in detail, including correlations between optical sensitization and supersensitization with the type of absorption spectrum of the adsorbed dye; the relations between the concentration of sensitizer, supersensitizer, and antisensitizer, and the efficiency of super- and antisensitization; the quenching of fluorescence of sensitizers by both types of perturbing molecules; and effects of nonplanar dyes on the photoconductivity of optically sensitized silver halide emulsions analogous to their photographic effects.
The Reactions of Radicals Produced by the Action of Sodium on Alkyl Iodides
Authors: Comstock A. A. , Rollefson G. K.
Published: January 2005

The products of the reactions of sodium vapor with methyl and ethyl iodide vapors have been analyzed. It has been found that in the reaction with methyl iodide the principal product is ethane, but considerable amounts of methane, ethylene, and hydrogen are also formed. With ethyl iodide the principal product was butane, with lesser amounts of ethane, ethylene, methane, and hydrogen. It was also noted that in the latter system considerable amounts of propane appeared which could be accounted for as a pyrolysis product of the butane formed. The results have been compared with those obtained by others with similar systems and with the results obtained in the photolyses of mercury dimethyl and mercury diethyl. It is concluded that at low temperatures the dominant reaction for both ethyl and methyl radicals is for two to combine to form a saturated hydrocarbon. At higher temperatures, disproportionation reactions and reactions of the radicals with other molecules must be taken into account and eventually become the dominant reactions.
Near Infrared Pleochroism. II. The 0.8–2.5μ Region of Some Linear Polymers
Authors: Glatt L. , Ellis J. W.
Published: January 2005

Polarized radiation is used to study the pleochroism of aligned specimens of polythene, Nylon, polyvinyl alcohol, polyvinyl chloride, and polyvinylidene chloride, in the 0.8–2.5μ overtone and combination region. Assignments of observed absorption bands to various vibration modes of (coupled) >CH2, N–H, and C=O groups are attempted. The symmetry of an infinite planar-zigzag >CH2 chain is discussed as an approximation to that of polythene and, to a lesser extent, Nylon. Some limitations in the interpretation of observed pleochroism and in the application of selection rules are discussed. A pleochroism study, with unpolarized radiation, is made of the molecular alignment in oriented ``Parowax.'' A study is made also of the rupture of the intermolecular N–H≡O bonds in molten and premolten Nylon.
The General Valence Orbitals Derivable by sp3 Hybridization
Authors: Torkington P.
Published: January 2005

An examination is made of the allowed sets of four sp3-hybrid orbitals satisfying the symmetry requirements of the point groups C2v and C3v, the object of the analysis being to aid in the formalization of the study of deviations from the ideal tetrahedral valence angle, found in systems of symmetry lower than Td. Tables of allowed interorbital angles are given.
Solutions of the Fermi-Thomas-Dirac Equation
Authors: Metropolis N. , Reitz J. R.
Published: January 2005

Solutions of the Fermi-Thomas-Dirac equation are given for 24 different elements. Both neutral atom and positive ion solutions are given. These results were obtained by evaluating the series expansion for the FTD function at small distances from the origin and by numerical integration of the differential equation at larger distances. The numerical solutions were done on the ENIAC.
Electric Moments of Polar Polymers in Relation to Their Structure
Authors: Debye P. , Bueche F.
Published: January 2005

From the observed angular dissymmetry of the light scattered by polymer solutions it has been possible to draw conclusions on the average size of the polymer coil. In general, the actual coil diameter found in this way is much larger than that calculated from a model with free rotation. (For polystyrene in benzene the factor is about 3.5.) This increase in size can satisfactorily be attributed to hindering of rotation around the chemical bonds. In order to obtain information about structural details of this hindered rotation, however, the size determination will have to be combined with evidence derived from other sources than light scattering. As such, the dipole moment, as derived from measurements of the dielectric constant of polymer solutions, obviously is a good choice. If a number of units are connected to each other in a chain, the contribution of the whole chain may be larger or smaller than would be the case if the units were free, depending on whether positions of parallelism or antiparallelism of the elementary electric moments are preponderant, taking the average over all the possible forms the coiling molecule can assume. A theory of this effect has been worked out, and experiments have been carried out. One of the examples is polyparachlorostyrene, for which the average contribution to the polarization of one chain element is substantially smaller in the polymer than that of the corresponding monomer.
Thermodynamic Investigations on Ternary Amalgams
Authors: Wagner Carl
Published: January 2005

Under certain conditions, interaction between positively charged metal ions in an alloy may be considered to be of minor importance as compared to interaction between conduction electrons and metal ions. Then it follows that the activity of a solute metal 2 dissolved in metal 1 will be increased by a third component if metals 2 and 3 change the valence electron/atom ratio in the same direction. Conversely, the activity of a solute metal 2 will be decreased by a third component if metals 2 and 3 change the valence electron/atom ratio in opposite directions. Reference is made to the change in the solubility of hydrogen in copper by zinc, tin, aluminum, platinum, and nickel as alloying elements, to the change in the vapor pressure of zinc dissolved in copper by aluminum and nickel, and to the change in the activity of alkali metals dissolved in mercury by thallium.

In addition, an equation is derived with the aid of which one may calculate the change in the activity of metal 2 dissolved in metal 1 due to the addition of a solute metal 3 if the changes in the activity coefficients with composition for the binary systems 1–2 and 1–3 are known and interaction between positively charged metal ions can be disregarded. This relation has been confirmed for the systems Hg–Li–Tl, Hg–Na–Tl, Hg–K–Tl, and Hg–Na–K.
Kinetics of the Thermal Decomposition of Di-t-Butyl Peroxide
Authors: Murawski J. , Roberts J. S. , Szwarc M.
Published: January 2005

The kinetics of the thermal decomposition of di-t-butyl peroxide were studied in the presence of excess toluene using a static and a flow system, the temperature range being 120° to 280°C. The decomposition was represented by the following mechanism: (CH3)3C. O. O. C(CH3)3→2(CH3)3. CO·(CH3)3. CO·→CH3·+CH3. CO. CH3  2CH3·→C2H6CH3·+C6H5. CH3→CH4+C6H5. CH2·CH3·+C6H5. CH2·→C6H5. CH2. CH3The rate of reaction was measured by the rate of formation of CH4+C2H6. It was shown that the decomposition is a homogeneous gas reaction of the first order. The activation energy seems to be 36±1 kcal/mole, corresponding to the frequency factor of the order 4.1014−7.1014 sec−1. It was shown that the rate of reaction is not influenced by the pressure of toluene and by the toluene/peroxide ratio. It remains the same even in the extreme case when no toluene is present, or when benzene is used instead of toluene. The rates of decomposition obtained in this study are in fair agreement with the rates obtained for the same reaction by Rust and Vaughan. The following values have been obtained for dissociation energies: D[(CH3)3. CO–OC. (CH3)3]=36 kcal/moleD[(CH3)3. CO–H]=106 kcal/moleD[(CH3)3·CO–OH]=39 kcal/moleand the heat of formation of (CH3)3.CO· radical has been estimated at −23 kcal/mole.
Infrared and Raman Spectra of Methylhydrazine and Symmetrical Dimethylhydrazine
Authors: Axford D. W. E. , Janz G. J. , Russell K. E.
Published: January 2005

Raman spectra for liquid methylhydrazine and sym-dimethylhydrazine, and infrared spectra for both liquid and vapor methylhydrazine and sym-dimethylhydrazine in the region 1600–650 cm−1 have been obtained. Frequency assignments are proposed for methylhydrazine and sym-dimethylhydrazine. The strong polarization of the Rayleigh scattering from these two compounds is explained on the basis of associated structures of approximately spherical symmetry.
Equivalent and Ionic Conductances for Sodium and Potassium Chlorides in Anhydrous Methanol at 25°C
Authors: Butler J. P. , Schiff H. I. , Gordon A. R.
Published: January 2005

The conductance of sodium and potassium chlorides has been determined in anhydrous methanol for concentrations from 0.0002 N to 0.01 N. For trace amounts of water, the decrease in equivalent conductance for a given electrolyte concentration is proportional to the water content, the proportionality factor being a function of the ionic strength. The results up to 0.002 N satisfy the Onsager-Shedlovsky equation. The limiting conductances, when combined with the transference data of the preceding paper, give the first precise limiting ionic conductances in an anhydrous solvent. The limiting values for chloride ion are the same for the two salts within experimental precision; but with increasing concentration, there are deviations from the Kohlrausch rule of independent ionic mobilities which are considerably greater than is the case in aqueous solution. The equivalent conductance data are in definite disagreement with Frazer and Hartley's results for the two salts in this solvent.
Fractionation of the Carbon Isotopes in Decarboxylation Reactions. IV. The Relative Rates of Decomposition of 1-C12 and 1-C13 Trichloracetate Ions
Authors: Bigeleisen Jacob , Allen Thomas L.
Published: January 2005

A precise determination of the relative rates of decomposition of 1-C12 and 1-C13 trichloracetate ions has been made. The 1-C12 ion has been found to decompose 1.0338±0.0007 times as fast as the 1-C13 ion into chloroform and bicarbonate at 70.4°C.

Trichloracetate ion has been found to undergo a decomposition reaction which gives chloride ion but no CO2, OH−, nor H+. The ratio of the rate constants for the production of Cl− and bicarbonate is 0.078.

The errors in the determination of the effect of isotopic substitution on the rates of chemical reactions are discussed. In the study of the isotopes of carbon, experiments using mass spectrometric analyses of C13 at the natural abundance level are capable of a precision of one order of magnitude better than ones in which the specific activity of C14 is determined by counting.
The Solution of Some Potential Problems in the Theory of Electrolytes
Authors: Booth F.
Published: January 2005

The Poisson-Boltzmann equation for the potential in an electrolyte is solved for the following cases:

(a) Electrolyte bordered by a uniformly charged plane; (b) two semi-infinite electrolytes of different composition separated by a plane boundary; (c) electrolyte confined between parallel charged planes; (d) uniformly charged cylinder immersed in an electrolyte; (e) electrolyte in a cylinder with charged walls; (f) electrolyte between two concentric charged cylinders; (g) solid charged sphere in an electrolyte; and (h) sphere of electrolyte immersed in another electrolyte extending to infinity, and of different composition.

All the problems discussed are of interest in the theory of colloids or emulsions. In each case a series solution in powers of a parameter involving the charge or charges on relevant surfaces is given. The first term of each series is the solution of the Poisson-Boltzmann equation when the so-called Debye-Hückel approximation is applied to the equation. The additional terms are built up from the first by an iterative method. No restrictions on the compositions of the electrolytes are required.
The Critical Constants of Polar Gases
Authors: Rowlinson J. S.
Published: January 2005

The range of usefulness of the virial expansion is discussed. It is shown that this expansion closely resembles the Beattie-Bridgman equation if terms up to the third virial coefficient are included. This suggests that the ranges of validity of the two equations may be similar—namely, almost up to the critical density. The virial expansion is therefore used to calculate the critical constants of both nonpolar and polar gases. These constants are much less sensitive to the dipole-energy than are the virial coefficients. The agreement with experiment is satisfactory.
Photoneutron Fission Analysis for U−235 in High Purity U−238
Authors: Macklin R. L. , Lykins J. H.
Published: January 2005

The photoneutron method for the analysis of U−235 in high purity U−238 is described. Special samples have been found to contain as little as 5 parts per million U−235. An upper limit for the thermal neutron fission cross section of U−238 can be set at 5×10−28 cm2.
Substituted Ethanes. III. Raman and Infrared Spectra, Assignments, Force Constants, and Calculated Thermodynamic Properties for 1,1,1-Trichloroethane
Authors: El-Sabban M. Zaki , Meister Arnold G. , Cleveland Forrest F.
Published: January 2005

Raman displacements, semiquantitative relative intensities, and quantitative depolarization factors for liquid 1,1,1-trichloroethane, and infrared wave numbers and percentage absorption for both the liquid and gaseous states in the region 400–5000 cm−1 were obtained and compared with previous data. A normal coordinate treatment, using the Wilson FG matrix method, was carried out, and a reasonable set of force constants was determined. Assignments were made for all observed bands of the infrared and Raman spectra. The heat content, free energy, entropy, and heat capacity at constant pressure were calculated for 9 temperatures in the range 298.16° to 1000°K. A comparison of calculated and observed entropy values indicated that the potential barrier hindering the internal rotation is about 2840 cal/mole, which leads to a value of 205±20 cm−1 for the torsional frequency and to 0.786×10−12 erg/radian for the torsional force constant.
Unimerism
Authors: Senior James K.
Published: January 2005

It is pointed out that, in the development of structural organic chemistry, those compounds which have no structural isomers play a crucial role. Since no general name has ever been given to compounds which meet this condition, they are here called ``unimers.'' It is further shown that the molecular formula of a unimer must necessarily fulfill certain mathematical conditions. These conditions are set forth in nine theorems. Some of these theorems are almost self-evident; for others, the proofs, although simple in plan, are exceedingly intricate in application. Consequently, the reader is referred for all proofs to a purely mathematical paper which will be published in the American Journal of Mathematics. Finally, a complete list of unimeric types is given.
Thermodynamics and Chemical Kinetics of One-Dimensional Nonviscous Flow through a Laval Nozzle
Authors: Penner S. S.
Published: January 2005

Explicit relations have been obtained for the enthalpy changes in one-dimensional nonviscous flow through a Laval nozzle, where arbitrary deviations from thermodynamic equilibrium of chemical composition and of internal electronic, vibrational, or rotational energy states may occur. These relations are of interest in connection with calculations on the effect of deviations from equilibrium on performance of jet engines.

Starting with the equation of continuity for a multicomponent mixture of reacting gases, criteria for near-equilibrium and for near-frozen flow with respect to chemical reactions are derived. The near-equilibrium criteria agree with results obtained previously. The near-frozen flow criteria are new and have not yet been applied to the study of chemical reactions during nozzle flow.