Volume 16, Issue 2, April 1987
Index of content:
16(1987); http://dx.doi.org/10.1063/1.555776View Description Hide Description
In this third review of a series, the literature values for the viscosity‐molecular weight relationship (Mark–Houwink–Sakurada) for poly(methyl methacrylate) have been critically evaluated. Although most of the studies have been concerned with conventionally produced poly(methyl methacrylate), some work has also been done with the isotactic polymer. The Mark–Houwink relations for the following solvents are discussed: benzene, toluene, acetone, chloroform, 2‐butanone, and tetrahydrofuran, as well as for several other infrequently used solvents. The values of the coefficient K in the relation [η]=K M 0.5 for several theta solvents are also reported.
16(1987); http://dx.doi.org/10.1063/1.555777View Description Hide Description
The paper contains accurate representations for the viscosity of the three polyatomic gases, carbon dioxide,methane, and sulfur hexafluoride, in the limit of zero density. These gases were studied because they possess permanent multipole moments of increasing order 4, 6, and 8, respectively. The correlations have associated uncertainties of ±0.3% around room temperature rising to ±1.5% at the low‐temperature extreme and to a maximum of ±2.0% at the high‐temperature extreme. The correlating equation for carbon dioxide is valid for the temperature range 200–1500 K, that for methane from 110–1050 K and that for sulfur hexafluoride from 220–900 K. It is shown that a two‐parameter law of corresponding states is inadequate for the representation of the data over these wide ranges of temperature.
16(1987); http://dx.doi.org/10.1063/1.555778View Description Hide Description
This paper contains a new representation of the viscosity of normal deuterium in the limit of zero density as a function of temperature. The correlation is based upon the semiclassical kinetic theory of polyatomic gases and a body of critically evaluated experimental data. The similarity of the intermolecular pair potentials of normal hydrogen and normal deuterium is employed to extrapolate the correlation for deuterium beyond the range of the experimental data. In the temperature range 250–350 K the accuracy of the representation of the viscosity is estimated to be ±1%, which deteriorates to ±2% at the lowest temperatures and to ±4% at the highest temperatures.
16(1987); http://dx.doi.org/10.1063/1.555779View Description Hide Description
The chemical thermodynamic properties of alkanethiol (RSH where R is an alkyl group) isomer groups from CH4S to C4H1 0S in the ideal gas phase have been calculated from 298.15 to 1000 K from tables of Stull, Westrum, and Sinke. In the absence of literature data on all isomers of higher isomer groups, the properties of isomers of C5H1 2S to C8H1 8S have been estimated using Benson group values. Equilibrium mole fractions within isomer groups have been calculated for the ideal gas state from 298.15 to 1000 K. For isomer group properties, increments per carbon atom have been calculated to show the extent to which thermodynamic properties of higher isomer groups may be obtained by linear extrapolation. Values of C ○ P , S°, Δf H°, and Δf G° are given for all species of alkanethiols from CH4S to C8H1 8S in SI units for a standard state pressure of 1 bar.
16(1987); http://dx.doi.org/10.1063/1.555780View Description Hide Description
16(1987); http://dx.doi.org/10.1063/1.555781View Description Hide Description
Extinction Coefficients of Triplet–Triplet Absorption Spectra of Organic Molecules in Condensed Phases: A Least‐Squares Analysis16(1987); http://dx.doi.org/10.1063/1.555782View Description Hide Description
A global least‐squares technique is developed to assist in the critical evaluation of data consisting of large sets of measurements. The technique is particularly designed to handle sets of data where many of the measurements are relative measurements. A linearization procedure is used to reduce the inherently nonlinear problem to a traditional multivariate linear regression. The technique developed here is used to evaluate extinction coefficients, ε’s, of triplet–triplet absorption (TTA) spectra of organic molecules in condensed phases. A previous assumption, that there are no solvent effects on the TTA spectra, is investigated and modified so that a group of compounds measured in benzene is treated separately. The set of 445 ε’s obtained from the global least‐squares fit, including these solvent effects, is presented in the accompanying tables. How these least‐squares results can be used in a hierarchy of TTA ε standards is discussed. Further solvent effects such as the separation of polar and nonpolar media and the influence of temperature are probed.
Evaluated Chemical Kinetic Data for the Reactions of Atomic Oxygen O(3P) with Unsaturated Hydrocarbons16(1987); http://dx.doi.org/10.1063/1.555783View Description Hide Description
Chemical kinetic data for reactions of O(3P) atoms with unsaturated hydrocarbons are compiled and critically evaluated. Specifically, the reactions considered include the interactions of the ground electronic state of oxygen atoms, O(3P), with alkenes, cycloalkenes, halogen substituted alkenes and ketenes, alkynes, halogen substituted alkynes, aromatic hydrocarbons, halogen substituted aromatic hydrocarbons and pyridine. All kinetic data considered were restricted to gas phase reactions. ‘‘Recommended’’ values of the rate parameters have been assessed and conservative uncertainty limits assigned to them.
16(1987); http://dx.doi.org/10.1063/1.555784View Description Hide Description
Wavelengths, intensities, and classifications for the molybdenum ions Mo VI to Mo XLII are compiled. A short review of the work on each stage of ionization is included. The data are critically evaluated and the best results, in our judgement, are quoted.