bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Considerations Concerning the Reactions Between Ethylene and the Halogens and Their Products
Authors: Sherman Albert , Quimby Oscar T. , Sutherland Richard O.
Published: January 2005

Ethylene may react with a halogen by a substitution reaction to give a vinyl halide and hydrogen halide, or the halogen may add to the double bond to give 1,2-dihalo-ethane or rearrange and give ethylidene halide. It is found that the symmetrical addition is favored in the case of each halogen. 1,2-dihalo-ethane, or the corresponding ethylidene compound may decompose to give ethylene and the halogen, or the vinyl halide and hydrogen halide. It is found that ethylene formation is favored in the bromine and iodine derivatives, whereas, in agreement with experiment, vinyl chloride and HCl would be produced from either 1,2-dichlor-ethane or ethylidene chloride. In most of the reactions considered mechanisms involving free radicals are slightly more probable than the corresponding unimolecular or bimolecular reactions.
The Ultraviolet Absorption Spectra of Simple Hydrocarbons III. In Vapor Phase in the Schumann Region
Authors: Carr Emma P. , Stücklen Hildegard
Published: January 2005

Absorption spectra measurements between λ = 2300A and 1500A were made for fourteen ethylenic hydrocarbons, which included four butenes, five pentenes, one hexene, two heptenes and two octenes. A comparative study of these results together with those from the earlier papers in the series has shown the existence of certain general relationships between the absorption spectra of all ethylenic derivatives. The number of alkyl groups bound to the carbon atoms of the C=C bond determines the wave number of the first absorption band; there is a progressive shift toward the visible with increasing number of alkyl groups but the nature of the alkyl group has almost no influence on the position of the first band; where two alkyl groups are bound to the same carbon atom (unsymmetrical substitution) or to different carbon atoms (symmetrical substitution), the wave number of the first band is very slightly different. The first band of these derivatives is tentatively assigned to an electronic excitation corresponding to the transition 1A1→1B1, predicted for the ethylene molecule. Usually one, but never more than three bands of this system could be seen because of overlapping with another group of bands of higher intensity. All of the sixteen olefines have this same intensity change, showing the existence of another electronic excitation. A third group of bands corresponding to a third electronic excitation can be seen clearly in the spectra of four hydrocarbons and may possibly be present but overlapping the lower frequency group in the other compounds. The bands are too broad and diffuse to admit of analysis of vibrational structure but certain recurring separations, which are probably related to the 1350 cm—1 vibrational frequency of ethylene, are evident. In the molecules of higher symmetry, where fewer transitions are permitted by the selection rules, there is less overlapping and therefore more discrete bands can be seen.
The Free Energies and Vapor Pressures of the Alkali Metals
Authors: Gordon A. R.
Published: January 2005

The free energies of the diatomic alkali vapors K2, Na2 and Li2 are calculated from spectroscopic data, and the equilibrium constants for the dissociation into the monatomic form are computed. With the aid of these constants, equations are deduced from the observed vapor pressures obtained by various investigators, which give the partial pressures of atoms and molecules in the saturated vapors for temperatures up to the normal boiling point. In the case of sodium and potassium, the entropy of the solid metal is computed from the vapor pressure equation, and is compared with that predicted by the third law of thermodynamics.
Electron Distribution in (NH4)2C2O4–H2O and the Structure of the Oxalate Group
Authors: Hendricks S. B. , Jefferson M. E.
Published: January 2005

The electron distribution of (NH4)2C2O4–H2O projected on (001) was obtained by a Fourier analysis making use of quantitative intensity measurements of x-ray scattering from (hk0). This analysis combined with a determination of the atomic parameters perpendicular to (001) gave the complete structure. Separations of covalently linked atoms in the C2O4— — group are C–C, 1.581±0.01A; C–O, 1.25±0.02A; and C–O, 1.23±0.02A with the angle O–C–O=129°±2°. In this compound the O–C–O parts of an oxalate group are in planes at an angle of 28° while in H2C2O4–2H2O, α and β H2C2O4 the parts are coplanar.
II. Calculation of Energy of H3+ Ion
Authors: Hirschfelder J. , Eyring H. , Rosen N.
Published: January 2005

The potential energies for linear symmetrical configurations of H3+ have been calculated by the same methods used in the previous paper (I). The energies at the minimum in kcal./mole and the corresponding distances between neighboring atoms in Bohr radii for the various approximations are: Heitler−London−91.92 at 2.00;H.L. plus polar−108.64 at 2.00;Wang Approx.−130.89 at 1.55;Wang plus polar−155.35 at 1.52.It follows from the use of the variational method that the energy of binding of a proton to H2 is greater than 46.8 kcal./mole. If we use the same Wang plus polar approximation for H2 and H3+ we obtain for this binding energy 63.11 kcal./mole. The reaction H2++H2→H3++H may be exothermal and cannot be more than slightly endothermal.
Potential Functions of Molecular Groups and the Vibrations of the Halogen Derivatives of Methane
Authors: Voge H. H. , Rosenthal Jenny E.
Published: January 2005

On the assumption of the invariance of the molecular groups YZ3 and YX formulas are given connecting the potential energy constants of the molecules YZ4, XYZ3, ZYX3, and ZX4. The validity of the assumption is tested for the series CH4, ClCH3, HCCl3, and CCl4; the consistency of the results definitely shows it to be a very good approximation. The application leads to a determination of the general potential functions of all four molecules. Frequencies of HCCl3 and DCCl3 are calculated from those of CH4, ClCH3, and CCl4, and are found to be in excellent agreement with the observed data. Predictions are made for the frequencies of ClCD3. A certain ambiguity exists for the constants for the perpendicular frequencies of both HCCl3 and ClCH3, since two different chemically acceptable sets will account for the observed frequencies. A discussion of the methane constants shows that, while individual constants are quite sensitive to various methods of determination, certain linear combinations of them, to which a definite physical meaning can be attached, are practically invariant. The methane constants are used to redetermine the constants computed by Sutherland and Dennison for ethane; they yield an entirely different set, which, however, is equally suited to an explanation of the frequencies.
Raman Spectrum of Crystalline Ammonium Chloride
Authors: Holmes F. T.
Published: January 2005

Crystalline NH4Cl was studied in its room temperature and high temperature forms. Cylindrical crystals were grown by sublimation in a special furnace. At room temperature vibrational frequencies were observed at 3146, 3041, 2824, 2010, 1768, 1709, 1407 and subsidiary frequencies at 3300, 3232 cm—1. In the high temperature modification vibrational frequencies were observed at 3102, 2801, 1931, 1655, 1400 cm—1.
The Reaction Rates of Propionic and Acetic Propionic Anhydrides
Authors: Barr E. S. , Plyler E. K.
Published: January 2005

The infrared absorption spectra of mixtures of water and acetic propionic and of propionic anhydrides have been measured in the region from 5μ to 6.4μ. The intensity of the bands was found to decrease with time. By using the relative intensity of the anhydride band the reaction rate was calculated for three concentrations. The reactions were unimolecular but the value of the reaction constant was different for each concentration, its value being approximately proportional to the concentration of the water. The value of the reaction constant of acetic propionic anhydride was about twice the value of the constant for propionic anhydride. A table is given of the values of the reaction constants for the different concentrations.
Sodium Resonance Radiation and the Polymerization of Ethylene
Authors: Jungers Joseph C. , Taylor Hugh S.
Published: January 2005

Ethylene has been found to quench the resonance radiation of sodium between 130 and 250°C. No measurable polymerization of ethylene results as a consequence of quenching, in contrast to previous results with excited mercury and cadmium. A catalytic polymerization of ethylene at sodium surfaces occurs above 250°C with an activation energy of 20 kcal. The inefficiency of the energy of sodium resonance radiation in producing polymerization is ascribed to unfavorable localization of the energy received by ethylene in the quenching process.
The Far Ultraviolet Absorption Spectra and Ionization Potentials of H2O and H2S
Authors: Price W. C.
Published: January 2005

The absorption spectra of H2O and H2S in the region below 1600A have been found to consist of various electronic series accompanied by comparatively little vibrational structure. The electronic series conform fairly well to Rydberg formulas the limits of which give 12.56±0.02 and 10.42±0.01 volts, respectively, for the ionization potentials of these molecules. The analysis fits in very well with Mulliken's prediction that the bands should be due to the excitation and removal of a nonbonding electron localized near the oxygen or the sulphur atom. A tentative rotational analysis given for some of the bands in H2S indicates that the moments of inertia suffer little change by the excitation. Suggestions with regard to plausible atomic term series related with the molecular series are put forward.
A Study of the Franck-Condon Principle
Authors: Coolidge Albert Sprague , James Hubert M. , Present Richard D.
Published: January 2005

The validity of the Franck-Condon principle has been investigated in connection with its application to the calculation of spectral intensities in the continuous radiation due to the transitions between the 1sσ2sσ 3Σg and the 1sσ2pσ 3Σu states of H2. For the latter state, a potential curve was constructed on the basis of the authors' theoretical calculations. For the former state, a curve was computed from spectral data by Dunham's method. Accurate wave functions for both states were determined by mechanical integration with the differential analyzer. Transition probabilities from the first four vibrational levels of the stable state were determined by mechanical integration, both for the case that the electric moment matrix element is constant (as assumed in the Franck-Condon method) and for the case that it is a linear function of the nuclear separation. In addition integrals were determined which permitted the calculation of the probability of excitation of the several vibrational levels by electron impact from the ground state, upon the basis of an extension of the Franck-Condon method. The spectral intensities so obtained are compared with those given by several forms of approximate calculation, and the discrepancies critically discussed. Comparisons are also made with the experimental work of Smith and of Finkelnburg and Weizel. It is concluded that the Franck-Condon principle leads to results definitely incompatible with their observations. Indications are found that other transitions than the one treated in this work are contributing appreciably to the radiation observed by Smith. An analysis of the spectrum observed by Finkelnburg and Weizel leads to a critical discussion of the method used by them in deducing the potential curve of the repulsive state, from which is drawn the conclusion that this curve is without quantitative significance.
The Decomposition of Ethylamine and Diethylhydrazine
Authors: Taylor H. Austin , Ditman John G.
Published: January 2005

The decomposition of ethylamine has been reinvestigated in the light of criticism of earlier work. The reaction has been shown to occur by a bimolecular no volume change decomposition into symmetrical diethylhydrazine and hydrogen followed by the decomposition of the hydrazine by a chain mechanism which is first order. The mechanism is shown to account for the induction period and its rapid variation with temperature and pressure, as well as accounting satisfactorily for apparent discrepancies and inconsistencies found by previous workers.
Reaction Products of Ethyl Alcohol and Sodium Hydroxide
Authors: Williams Dudley , Bost R. W.
Published: January 2005

A study has been made of the products formed when sodium hydroxide and ethyl alcohol react in the absence of water. Evidence has been found which indicates a reaction in which sodium ethylate and water are produced. Three types of tests have been made to determine the amount of water formed. The copper acetylide method, a volumetric method, and a method involving infrared absorption measurements all indicate a reaction which goes from 75 to 100 percent toward completion.
The Structure of Ice III
Authors: McFarlan Ronald L.
Published: January 2005

The stability of the high pressure ice forms discovered by Tammann and Bridgman at very low temperatures and atmospheric pressure has made it possible to obtain x-ray diffraction photographs of these forms. Since ice III is extracted from the press by taking it through the ice II region the precautions taken to avoid consequent misinterpretation of the ice III films are given. The analysis of the ice III diffraction patterns leads to a body-centered orthorhombic structure, and a unit cell of dimensions a=10.20A, b=5.87A, and c=7.17A. The unit cell contains sixteen molecules, has the symmetry of space group Vh26-Ibam, and leads to a value for the density of 1.105 g per cc. Each oxygen ion is surrounded by a distorted tetrahedron of oxygen ions in a manner similar to that of ice I. An arrangement of the hydrogen atoms is proposed which makes the ice III lattice ionic. The volume decrease in the ice I—ice III transition is shown to be the result of a rearrangement of the oxygen ions. A simple transition mechanism is described, which is used to interpret some of the phenomena observed by Bridgman. The nature of the ice II—ice III transition is also discussed. A correlation between the latent heat of the solid-solid reactions involving ice I, ice II, ice III and the H–O–H bond angles is suggested. Some remarks are made concerning the liquid-solid reaction at high pressure. A brief description of some qualitative results obtained from the unanalyzed ice V and ice VI films is made. A summary of all the conclusions drawn from the high pressure ice investigations is made.
The Limiting High Temperature Rotational Partition Function of Nonrigid Molecules I. General Theory. II. CH4, C2H6, C3H8, CH(CH3)3, C(CH3)4 and CH3(CH2)2CH3. III. Benzene and Its Eleven Methyl Derivatives
Authors: Kassel Louis S.
Published: January 2005

I. The method given by Eidinoff and Aston for calculating the limiting high temperature rotational partition function has been further simplified. An important special case, comprising molecules which may be represented by a rigid framework to which symmetrical tops are attached in any position is developed. II. The methods of the preceding part are applied to the series of methyl derivatives of methane, and to the completely nonrigid molecule n-butane. The calculated entropies at 25°C show the same general variation with chain length and number of branches as has been found experimentally from the third law. III. The entropies of all the isomeric methyl derivatives of benzene are calculated. Comparison with third law values for the liquids is hampered by lack of reliable vapor pressure data and of vibration frequencies, but there are no major discrepancies which must be attributed to either the calculated or the observed entropies.
A Mechanism for the Decomposition of Ethylene Oxide
Authors: Sickman Darrell V.
Published: January 2005

The thermal decomposition of ethylene oxide exhibits an induction period, and is inhibited by the addition of inert gases. The assumptions that ethylene oxide mainly isomerizes to acetaldehyde, but at the same time produces free radicals which induce a chain decomposition of the acetaldehyde, and that the recombination of methyl radicals requires a third body lead to expressions for the length of the induction period and the pressure change during a run in qualitative agreement with experiments by Heckert and Mack.
On the Isotope Corrections in Molecular Spectra
Authors: Van Vleck J. H.
Published: January 2005

According to the simple theory of the rigid rotator and harmonic oscillator, the coefficients of J(J+1) and (v+½) in the energy should be inversely proportional to respectively the reduced mass and the square root thereof. Actually various small corrections, important only in compounds containing hydrogen or deuterium, make the mass dependence slightly different, and hence, at least in principle, explain why spectroscopic observations may yield slightly incorrect mass ratios for isotopes. The corrections are due to four causes (a) anharmonicity, (b) interaction between vibration and electronic motion even when perturbations between different electronic states are neglected, (c) L uncoupling or in other words perturbations between states differing by one unit in Λ, (d) interaction between states of equal Λ. The formulas for the various corrections are collected—some old, some new or more exact than previously. The relative magnitudes of the different effects are estimated. Incidentally, perturbations between states of equal Λ are studied in general. They should increase in intensity with the vibrational quantum number v, all other things being equal, in contrast to the perturbations due to L uncoupling, which increase with J. The electronic isotope shift, or displacement in the absolute value of the energy is also treated. Here the correction for the motion of the center of gravity of the molecule, usually neglected, is shown to be fully coordinate in importance with other terms. Shifts for ultraviolet lines of hydrogen are calculated with the Wang wave functions, and agree qualitatively with experiment. A concluding section is included on the mean square angular momentum of H2, which enters in connection with diamagnetism and the Stern-Gerlach effect.
The Free Energy of Iodine and Hydrogen Iodide from Spectroscopic Data
Authors: Murphy G. M.
Published: January 2005

Partition functions have been calculated for HI, I2 and I atom between 298.1 and 1500°K from spectroscopic data and the results have been fitted to a free energy equation of the usual thermodynamic form which may be differentiated and integrated to give change of heat content, specific heat and entropy for chemical reactions involving HI, I2, I and H2. The experimentally determined equilibrium constants for the reactions I2→2I and HI→½H2 +½I2 have been compared with the theoretical equilibrium constants. For the latter reaction, it is shown that the results of Bodenstein may be in error due to incorrect temperatures. Reliable values have been given for the heat of dissociation of iodine and hydrogen iodide at 25°C.
The Isotope Effect in the Evaporation of Lithium, Potassium and Rubidium Ions
Authors: Brewer A. Keith
Published: January 2005

Abundance ratio measurements are necessarily complicated by the possibility of an isotope effect at the source. In the emission of positive thermions of lithium, potassium and rubidium the extent to which the ion ratio represents the atom ratio within the source can be estimated by observing the change in the abundance ratio as a function of the percent of alkali evaporated. In the case of lithium an initial ratio of Li7/Li6=11.60 was observed; the abundance ratio followed the computed ratio for ideal evaporation until the lithium was 40 percent exhausted, beyond which it fell below the ideal value. The abundance ratios of K39/K41=14.22 and Rb85/Rb87=2.59 remained almost unchanged during the process of exhaustion. It is apparent therefore that a correction factor needs to be applied to the ion abundance ratio for lithium, but is unnecessary for potassium and for rubidium. The atomic weights computed from the abundance ratios are Li=6.939, K=39.094 and Rb=85.46.
The Acid-Base Catalysis of the Mutarotation of Glucose in Protium Oxide-Deuterium Oxide Mixtures
Authors: Hamill W. H. , La Mer Victor K.
Published: January 2005

The kinetics of the mutarotation of glucose has been studied in protium-deuterium oxide mixtures (H2O–D2O) to ascertain the effect of substituting deuterium for hydrogen upon catalysis by the aqueous solvent, by the acid ion, by an anion base and the conjugate molecular acid. The velocity of the water catalyzed reaction varies linearly with the fraction of heavy glucose and depends only indirectly upon the composition of the water. The velocity of the acid ion catalysis varies linearly with the H2O–D2O content. For acetate ion catalysis the rate varies linearly with the fraction of D2O or of DOAc. Measurements of the temperature coefficient show that the observed decrease in the rate of the water catalyzed reaction arises primarily from a decrease in the entropy of activation (B) and not from an increase in the energy of activation (Eact). A method has been devised for determining whether or not any property depends linearly upon the deutero fraction of a substance which may assume two isotopic forms, HX and DX. For the available data on the inversion of sucrose, DX has been identified with D+. For the present work on the water catalyzed mutarotation of glucose, DX has been identified with heavy glucose.
Studies of Reactions Induced by the Photoactivation of the Water Molecule. I
Authors: Fricke Hugo , Hart Edwin J.
Published: January 2005

Unbuffered gas free solutions of methyl alcohol have been irradiated with ultraviolet light in the wave-length range longer than 1850A and it is found that reactions involving the methyl alcohol occur, induced by the photoactivation of the water molecule. Gas free water itself is not changed by the irradiation. Products initially obtained in the water-photosensitized reaction are hydrogen as the only gas and a small amount of formaldehyde accounting for 10 to 20 percent of the hydrogen produced. The direct photoactivation of the methyl alcohol leads to its decomposition according to CH3OH+(hv) = CH2 : O+H2. The spectral limit for the water-photosensitized reaction is in the neighborhood of 2000A.
The Dispersion of Sound in Oxygen
Authors: Sinness Lester S. , Roseveare W. E.
Published: January 2005

The velocity of 1000-cycle sound wave in oxygen of various degrees of humidity at 26.5°C has been measured. The velocity behavior indicates that the water molecules are effective in bringing the heat capacity of the first vibrational state of the oxygen molecule into equilibrium with the sound wave. The dispersion change in velocity amounts to 0.16 percent. Intensity measurements agree with velocity data in fixing the center of the dispersion region between 1 and 3 mm partial pressure of water, which is in agreement with the values calculated from Knudsen's studies of rates of decay at higher frequencies.
The Limiting High Temperature Rotational Partition Function of Nonrigid Molecules IV. Ethylene, Propylene, 1-Butene, Cis and Trans 2-Butene, Isobutene, Trimethylethylene, Tetramethylethylene and Butadiene V. Equilibrium Constants for Reactions of Paraffins, Olefins and Hydrogen
Authors: Kassel Louis S.
Published: January 2005

IV. Methods previously developed by Eidinoff and Aston and by the writer are used to calculate the limiting high temperature rotational partition function and hence the translation-rotation entropy for the substances named in the title. The results are compared with third law values wherever possible. The agreement is fairly good in most cases, but the calculated values probably yield more accurate structural entropy differences. V. A consistent set of frequencies for methane, ethane, propane and butane is selected, and the corresponding vibrational contributions to —F/T and H/T are tabulated. Equilibrium constants for the dehydrogenation reactions of ethane, propane, normal and isobutane are calculated and compared with experimental values. Systematic deviations are found which would be removed if the experimental equilibrium constants were reduced by a factor of 3, if the experimental hydrogenation heats were reduced by 1500 cal., or if the vibrational contribution to —F/T at reaction temperatures were 2.5 cal./deg. greater for an olefin (excluding the torsional frequency) than for the corresponding paraffin. Approximate equilibrium constants are calculated for the reactions 2C2H4=C4H8, CH4+C2H4=C3H8, CH4+C3H6=C4H10 and C2H6+C2H4=C4H10.
Remarks Concerning the Formation and Crystallization of Vitreous Media
Authors: Richards William T.
Published: January 2005

The various characteristics of the liquid-glass transition are examined in an attempt to establish the hypothesis that liquid or vitreous properties depend upon the relation between the thermal relaxation time and the time of measurement, and not upon any discontinuous allotropic change at a fixed temperature. In the course of this survey it is found that the relaxation time involved in the liquid-glass transition for the heat capacity of glucose must be far less than that for the molecules, and is therefore probably that characterizing rotations of groups within the molecules, or certain modes of vibration of atoms or groups. No need is found from any of the measurements examined for the postulation of a ``vitreous state of aggregation,'' since all the properties of glasses appear to be those of undercooled liquids of high viscosity. Since the viscosity of laboratory glass is too high to permit its devitrification within a reasonable time, a mechanism involving surface solution is suggested by means of which observed phenomena may be explained.
The Homogeneous Unimolecular Decomposition of Gaseous Alkyl Nitrites VI. The Decomposition of n-Butyl Nitrite
Authors: Steacie E. W. R. , Smith W. McF.
Published: January 2005

The decomposition of n-butyl nitrite has been investigated from 5 to 40 cm pressure in the temperature range 170 to 212°C. The reaction is homogeneous and first order. The mechanism is, in the main, the same as with the lower members of the series. The reaction is, however, complicated by the formation of condensation products and the results are therefore less accurate than those obtained with the lower members of the series. The activation energy is approximately the same as those of the other nitrites. The velocity constant at 189.9°C is 8.88×10—4 sec.—1, as compared with 0.97 for methyl, 1.89 for ethyl, and 3.95 for n-propyl nitrite.
Transfer of Rotational Energy in Molecular Collisions I. Elementary Processes Which Lead to Abnormal Rotation of the HgH Molecule
Authors: Rieke F. F.
Published: January 2005

By the application of photographic photometry, the intensity distribution within the HgH 4017 band excited by mercury-sensitized fluorescence has been studied as a function of the pressure of nitrogen and the pressure of water vapor present in the fluorescence tube. From the effect which the foreign gases exert on the observed distribution of molecules among rotational levels, conclusions are drawn regarding the transfers of energy which occur in collisions of the HgH molecule with metastable Hg atoms and with normal H2O and N2 molecules. The proportion of excited HgH molecules with rotational energy greater than 0.2 volt greatly exceeds the thermal value under all circumstances; the excess rotational energy has its source in the two following processes. In a collision between an unexcited HgH molecule and a metastable Hg atom, the excitation energy of the latter is sometimes taken up as both rotational and electronic energy of the HgH molecule. In a collision between a normal N2 molecule and a highly excited HgH molecule, part of the electronic and vibrational energy of the latter is converted into rotational energy.
Atomic Dimensions from the Coefficients of Compressibility and Thermal Expansion
Authors: Djang G. F.
Published: January 2005

Starting from the equation of state p—K(V—V0)/V0 = RT/V—V0, the relation αa/β = R/(V—V0) is derived, where V0 is identified with the actual volume occupied by one mole of atoms or molecules. Values of the radii of atoms for different elements are calculated from this relation and compared to the values obtained from crystal analysis. Possibility of using the relation αa/β = R/(V—V0) to estimate molecular dimensions in the liquid state is also referred to.
Fluorescence of Chlorophyll in Its Relation to Photochemical Processes in Plants and Organic Solutions
Authors: Franck J. , Wood R. W.
Published: January 2005

The intensity of the fluorescence of chlorophyll in organic solutions in its relation to photochemical reactions can be explained by the assumption that the excited chlorophyll, which is free from adsorbed molecules, has a small probability of reemitting light as fluorescence, and a greater probability of predissociating into a hydrogen atom and monodehydrochlorophyll. In the presence of oxygen the product of dissociation will react with it. If acceptor molecules (RH) for oxygen are added to the solution, they will take over the excitation energy and protect the chlorophyll against oxidation, while they themselves will be oxidized; the first step being the dissociation of RH into R and H. The energy transfer may take place by impact of the second kind or as an intramolecular energy exchange within a complex molecule H Chph RH which will dissociate into H Chph R and H. The formation and consumption of the complex radical H Chph R is responsible for the change of intensity of the fluorescence with the time of irradiation which occurs in the presence of oxygen and some acceptor molecules in organic solutions. Analogous intensity time relations have been found and qualitatively described by Kautsky and his co-workers for the fluorescence of living leaves in the presence of oxygen. Quantitative measurements of these curves under various conditions form the experimental part of this paper. All observations can be interpreted by the assumption that not only photosynthesis but also photoxidation of organic substances adsorbed to chlorophyll takes place in the plant. The hypothesis is suggested that photoxidation is responsible for the so-called light saturation of photosynthesis in living plants.
Acoustical Studies V. The Collision Efficiencies of Deuterium and Hydrogen in Exciting the Lower Vibrational States of Ethylene
Authors: Richards William T.
Published: January 2005

Measurements on the velocity of sound in ethylene-deuterium mixtures indicate that deuterium is less efficient than hydrogen in exciting the lower vibrational states of ethylene by a factor of about 8 per collision. This difference in behavior substantiates a previous hypothesis that the marked efficiency of hydrogen in this respect may be due to its uniquely small moment of inertia. It also appears possible, however, that the mechanics of the collision process might provide an explanation. The suggestion that hydrogen at 30°, 780 mm, and 450 kc shows dispersion due to lagging of the rotational terms, which has been justly criticized by other writers, is withdrawn.
Acoustical Studies VI. Observations Concerning the Behavior of Formic and Acetic Acid Vapors
Authors: Strother C. O. , Richards W. T.
Published: January 2005

The thermal decomposition of formic acid at 60°, the lowest temperature at which its vapor pressure is great enough to permit the determination of the velocity of sound, was sufficiently rapid to make accurate measurements impossible. Measurements on acetic acid vapor at several temperatures are reported which serve to place the lower limit of the dissociation rate at about 104 sec.—1 at 85° and 174 mm. Reasons for the variability of the velocity of sound in acetic acid, which is in sharp contrast with the behavior of nitrogen tetroxide, are discussed.
Relation of the States of the Carbon Atom to Its Valence in Methane
Authors: Voge H. H.
Published: January 2005

An extended Heitler-London-Pauling-Slater calculation is given for methane. In addition to the usual quadrivalent configuration of the carbon atom, divalent and other configurations with which it may ``resonate'' are considered, in order to ascertain whether or not s2p2 carbon plays a more important part than usually is supposed. The mathematical formulation, an example of the use of the vector model, leads to a seventh degree secular equation, which is solved for empirical values of the integrals. The influence of resonance upon the energy is found to be small, but not negligible, and increases the stability of the molecule about 1.2 volts over the value for the usual Pauling-Slater configuration. The state of the carbon atom when it forms four electron-pair bonds is obtained explicitly in terms of the atomic states, and is found to comprise 5S, 3D and 1D of sp3, together with 3P and 1D of s2p2 and of p4. This, the ``valence state'' of Van Vleck, is 7 volts above the ground state of the carbon atom; resonance lowers it about 2.5 volts. The resonance causes a greater modification in the wave function and in the valence state than it does in the energy. In the final section the relative energies of CH, CH2, CH3 and CH4 are examined under the approximation of electron pairing, and are shown to have the regularly graded values of 4.0, 8.0, 12.1 and 17.0 volts when the experimental values for CH and CH4 are used to determine the unknown integrals. There is no indication that CH2 occupies a favored position, and the valence of four for carbon remains understandable in the light of the theory.
On the Theory of Dielectric Polarization
Authors: Kirkwood John G.
Published: January 2005

The polarization of a nonpolar dielectric in a homogeneous field is investigated from a molecular point of view. A statistical calculation of the average local field in a molecule shows that fluctuations in the induced molecular moment give rise to a deviation from the Lorentz field. As a result, small but significant deviations from the Clausius-Mosotti formula are to be expected. A series expansion for (ε—1)v/3 of the following form is obtained (ε−1)v/3=P0[1+(1+γ+σ)P0/v+···],where ε is the dielectric constant, v the molal volume and P0 the molecular polarization. The coefficients in the corresponding expansion of the Clausius-Mosotti formula are all equal to unity. The correction γ, arising from translational fluctuations, is about 0.1 for most substances. The correction σ depends upon the optical anisotropy of the molecule and its shape.
Studies on the Decomposition of Azomethane III. Effect of Various Inert Gases
Authors: Sickman Darrell V. , Rice O. K.
Published: January 2005

Data are presented on the decomposition of azomethane in the presence of several inert gases, relative activation efficiencies being given in Table II. The low efficiency of helium as compared to the other gases is taken as indicating that exchange of vibrational energy between molecules is more probable than the transition of translational into vibrational energy. The results are compared with other pertinent data, and the probable mechanism of energy exchange is discussed. Finally, some preliminary data on the effect of azomethane on reactive gases are given.
The Effect of Structure Upon the Reactions of Organic Compounds. Temperature and Solvent Influences
Authors: Hammett Louis P.
Published: January 2005

The effect of a substituent upon the heat of ionization of an organic acid is far from identical with its effect upon the free energy of ionization. In the case of benzoic acid derivatives the entropy of ionization varies with structure in a way which can be predicted from the temperature dependence of the dielectric constant of the solvent, and which is closely correlated with the effect of a change in the dielectric constant of the solvent upon the relative strengths of substituted and unsubstituted acids. The behavior of aliphatic acids is more complicated, probably because of their less rigid structure. Similar considerations apply to the effect of changes in structure of reactant upon other equilibria and upon reaction rates.
The Absorption Spectra of Samarium Tungstate and of Samarium Molybdate at Low Temperatures
Authors: Freed Simon , Haenisch Edward L.
Published: January 2005

As a preliminary to a study of the relation between the fluorescence and the absorption spectra of crystals, we photographed the absorption spectra of single crystals of Sm2(WO4)3 and of Sm2(MoO4)3 at 78°K, 113°K, 169°K, and 298°K. Evidence was found that an activated state 76 cm-1 from the basic state exists in the tungstate. The general patterns of the spectra of the tungstate and of the molybdate are not the same, indicating that the crystals do not belong to the same space group, an inference likely to be made from crystallographic data. There is also evidence for a dissociation, perhaps an incipient dissociation in the lattice, as if the tungstate and especially the molybdate dissociated into the basic and acidic oxides within the single crystal.
The Free Energy of Hydrogen Cyanide from Spectroscopic Data
Authors: Gordon A. R.
Published: January 2005

The free energy and heat content of gaseous hydrogen cyanide are computed from spectroscopic data, and the equilibrium constant for the reaction involving the formation of the gas from its elements is tabulated. The results are in good agreement with the experimental value for the free energy of formation obtained by Lewis and his associates, but are in definite disagreement with the results of Badger. The equilibrium constant for the exchange reaction with deuterium is also tabulated. From the spectroscopic entropy for the gas and the most recent density data, the entropy of liquid hydrogen cyanide is estimated.
The Transfer of Energy in Molecular Systems
Authors: Gershinowitz Harold
Published: January 2005

A method of investigating problems of energy transfer, by means of potential energy surfaces, outlined in an earlier paper, has been extended to include a more general type of surface. The probability of energy transfer among atoms has been related with the rate of change of curvature of the equipotential lines. It has been shown that the relative reactivity of atoms depends on the degree of excitation of the system. An explanation has been suggested for the discrepancy existing between the data on the relative efficiencies of the inert gases as obtained from sound dispersion experiments and from reaction rate measurements.
The Activity Coefficient of Copper Sulphate in Aqueous Solution
Authors: Wetmore F. E. W. , Gordon A. R.
Published: January 2005

The electromotive force of the cell Cu two phase amalgam/CuSO4/Hg2SO4, Hg has been measured with solutions whose concentrations vary from 0.02 molal to saturation, and for temperatures from 15°C to 45°C. From these measurements and from freezing point and calorimetric heat of dilution data, activity coefficients have been calculated, and the value of E° for the cell has been determined. The results are in reasonable agreement with those of Nielsen and Brown and of Getman, but are in definite disagreement with the results of Lebettre.
Studies in the Autoxidation of Monolayers I. The Mechanism of Autoxidation of Maleic Anhydride β-Elaeostearin
Authors: Gee Geoffrey , Rideal Eric K.
Published: January 2005

The autoxidation of monolayers of maleic anhydride β-elaeostearin is examined in detail and a free radical mechanism proposed. The effect of temperature and pressure on the rate of oxidation over a very wide pH range has been investigated, and the variation of oxidation rate with pH shown to be of the form to be anticipated from the postulated mechanism. The absolute values of such constants as can be separately determined are consistent with the physical picture of the process.
Bond Force Constants and Vibrational Frequencies of Some Hydrocarbons
Authors: Glockler George , Wall F. T.
Published: January 2005

By use of valence forces, the normal coordinate method of treating vibrations has been applied to a number of related molecules and twenty-nine frequencies have been calculated and compared with experiment. The molecules considered are methylacetylene, dimethylacetylene, acetylene, diacetylene, ethane and methane. The frequencies calculated include all of the nondegenerate frequencies for the above molecules and the degenerate frequencies of methane. A set of five force constants has been applied to all of the molecules with fairly good results. The calculations have been carried out for both liquids and gases, a slightly different set of force constants being assigned to each state of aggregation.
Interaction in Molecules Between Rotation and Slightly Anisotropic Oscillations
Authors: Nielsen Harald H.
Published: January 2005

The problem of the interaction between rotation and oscillation in two dimensionally slightly anisotropic molecules is considered quantum mechanically on the basis of model rotating only about an axis normal to the plane in which the oscillations take place. The energy of the molecule in the ground state becomes (h/2)(v1+v2)+K2h2/8π2A while for the upper states the energies are E=h(ν1+ν2)+(K2+ζ2)h2/8π2A±((Δν/2)2+(Kh/4π2A)2ζ2)12, where ζ is a quantity depending upon the normal coordinates which in general is not an integer. The selection rules are such as to enhance the intensities of the set of lines in the sides of the two bands adjacent to each other at the expense of the set of lines in the sides of the bands farthest away from each other. The spacings between rotational lines of the first set converge rapidly toward a limiting value of (1-ζ)h/4π2A, while for the other set the spacings approach a value (1+ζ)h/4π2A.
The Dielectric Constant of Isopropyl Alcohol Vapor
Authors: Stranathan J. D.
Published: January 2005

The dielectric constant of isopropyl alcohol vapor has been measured at 12 different temperatures between 26.8°C and 190.4°C. At each temperature, measurements were made at many different vapor pressures. It is emphasized that this procedure is highly desirable. The slope, obtained by least squares, of the resulting (K-1)/(K+2) versus pressure curve gives one point on the Debye line. Twelve such points were obtained. Unusually pure isopropyl alcohol was used. The data fall on a Debye line whose equation as obtained by least squares is: [(K−1)/(K+2)]RT/p′=(17.40±0.41)+(17,490±155)/T. This yields a value (1.682±0.007) × 10-18 e.s.u. for the electric moment of the isopropyl alcohol molecule. These results agree closely with some previously unreported measurements made by the author three years ago.
Quantitative Relationships Between Light Absorption and Spectral Sensitivity of Dye-Sensitized Photographic Emulsions
Authors: Leermakers J. A.
Published: January 2005

Quantitative measurements of light absorption and photographic sensitivity for orthochromatic and panchromatic films over the wave-length region λ4000–7000 have been made. The results show excellent correspondence between light absorption of the dyed silver bromide emulsion and its sensitivity over the entire wave-length region for the panchromatic film. For equal absorption, the orthochromatic film is less sensitive in the green than in the blue. It is concluded for the panchromatic sensitizing, that transfer of energy from the dye to the silver halide is very efficient. Possible mechanisms of the sensitizing process are discussed.
Surface-Dye Concentration Relationships in Sensitized Photographic Emulsions
Authors: Leermakers J. A. , Carroll B. H. , Staud C. J.
Published: January 2005

A study has been made of the relationship between the total surface of silver halide in a photographic emulsion and the concentration of sensitizing dye necessary to produce maximum sensitizing. It was found that the amount of dye producing maximum sensitizing is directly proportional to the silver halide surface. Approximate calculations indicate that at optimum sensitizing concentration, the sensitizing dye is adsorbed to the silver halide grains in a monomolecular layer.
The Crystal Structure of Potassium Metaborate, K3(B3O6)
Authors: Zachariasen W. H.
Published: January 2005

In order to find the configuration of the metaborate group the crystal structure of potassium metaborate was determined. The crystals are rhombohedral ar = 7.76A, α = 110° 36′ with six molecules KBO2. The density is 2.348. The space group is R3̄c(D3d6). All atoms are lying on twofold axes at positions: ±(u, ½—u, ¼) ↺ . The parameters were determined by means of two-dimensional Fourier analyses:Ku=0.689±0.003,Bu=0.361±0.006,OI0.465±0.006,OII0.146±0.006.The metaborate radical is (B3O6)—3, a ring of three BO3 triangles, rather than the endless chain of BO3 triangles found in CaB2O4. The BO3 groups are slightly distorted, the B–O distances being 1.33A, 1.38A and 1.38A, the O–O distances 2.30A, 2.38A and 2.38A. The nine particles of the radical lie in one plane. Potassium is surrounded by seven oxygen atoms at a distance 2.82A.
An Electron Diffraction Study of the Grain Boundaries in Iron
Authors: Morgan Raymond , Steckler Sylvia , Miller Bernard L.
Published: January 2005

Grain boundary membranes, left after the dissolution of iron in ammonium persulphate solution, were studied by means of electron diffraction to determine whether crystalline materials are present in the membranes, and if present to identify the crystals. Samples of untreated and heat-treated transformer iron, and heat-treated electrodeposited iron were used. It was found that heat-treated electrodeposited iron left residues which were suitable for study by electron diffraction when supported by Resoglaz backing films. From the electron diffraction patterns obtained, identification was made of the presence of Fe3C and of αFeOOH. It is suggested that the αFeOOH did not exist originally in the grain boundaries, but may have been formed by some chemical reaction either between iron and ammonium persulphate, or between some grain boundary constituent such as an iron oxide and the persulphate solution. The method of studying grain boundary materials does not afford a complete analysis, but it is believed that it makes possible important contributions since the presence of crystalline materials in the residues may be detected.
On the Correlation of Fluidity Curves with Freezing Point Curves in Binary Systems
Authors: Ewell Raymond H.
Published: January 2005

Binary systems which form crystalline compounds nearly always exhibit negative deviations from the ideal laws for liquid solutions of the type G = N1G10+N2G20 , where N is mole fraction and G may be volume, heat content, vapor pressure or fluidity. The deviations from ideality are often approximately parabolic functions of the molecular composition with the maximum deviation at or near 50 mole percent. In the case of fluidity this type of deviation is observed whatever the composition of the crystalline compound or compounds which occur in the system, leading to the conclusion that there is no correlation between the position of the maximum fluidity deviation and the composition of the crystalline compounds indicated by the freezing point curve. The bearing of this conclusion on the question of compound formation in the liquid is discussed.
Ratio of Specific Heats of Air, N2, and CO2 as a Function of Pressure by the Ultrasonic Method
Authors: Hubbard J. C. , Hodge Alfred H.
Published: January 2005

Measurements have been made by Hodge of ultrasonic velocities at 27°C at pressures from 1 to 100 atmos. in air and N2 and at 1 to 60 atmos. in CO2. The results for air and N2 combined with the respective compressibility data of Holborn and Otto give at 27°C for air, values of γ between 1.406 at 1 atmos. and 1.580 at 100 atmos., and for N2, 1.403 at 1 atmos. to 1.564 at 100 atmos. The acoustic velocities in CO2 combined with the compressibility data of Amagat, give for γ at 27°C values from 1.304 at 1 atmos. to 3.524 at 60 atmos. These and the other results between these limits are in excellent general agreement with the few results in this temperature and pressure region available for comparison.