Volume 36, Issue 2, June 2007
Index of content:
36(2007); http://dx.doi.org/10.1063/1.2436891View Description Hide Description
Vibrational zero-point energies (ZPEs), as determined from published spectroscopic constants, are derived for 85 diatomic molecules. Standard uncertainties are also provided, including estimated contributions from bias as well as the statistical uncertainties propagated from those reported in the spectroscopy literature. This compilation will be helpful for validating theoretical procedures for predicting ZPEs, which is a necessary step in the ab initio prediction of molecular energetics.
IUPAC-NIST Solubility Data Series. 82. Alcohols with Water—Revised and Updated: Part 3. Alcohols with Water36(2007); http://dx.doi.org/10.1063/1.2383067View Description Hide Description
The solubility and related liquid–liquid equilibria in systems are exhaustively and critically reviewed. Reports of experimental determination of solubility in 13 chemically distinct binary systems that appeared in the primary literature prior to end of 2004 are compiled. 12 systems are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated alcohols was used.
IUPAC-NIST Solubility Data Series. 82. Alcohols with Water—Revised and Updated: Part 4. C7 Alcohols with Water36(2007); http://dx.doi.org/10.1063/1.2389037View Description Hide Description
The mutual solubility and related liquid-liquid equilibria of alcohols with water are exhaustively and critically reviewed. Reports of experimental determination of solubility in 20 chemically distinct binary systems that appeared in the primary literature prior to end of 2004 are compiled. For 14 systems sufficient data are available to allow critical evaluation. All data are expressed as mass percent and mole fraction as well as the originally reported units. In addition to the standard evaluation criteria used throughout the Solubility Data Series, a new method based on the evaluation of the all experimental data for a given homologous series of saturated alcohols was used.
36(2007); http://dx.doi.org/10.1063/1.2717223View Description Hide Description
The latest evaluation of atomic weight determinations and other cognate data has warranted 16 changes for the standard atomic weights of the elements, , from those published previously in the Table of Atomic Weights 2001. The revised standard atomic weight are as follows: , , , , , , , , , , , , , , , . A recommendation is made that values of all carbon-bearing materials be measured and expressed relative to Vienna-Pee Dee Belemnite on a scale normalized by assigning consensus values of to L-SVEC lithiumcarbonate and to NBS 19 calciumcarbonate.
36(2007); http://dx.doi.org/10.1063/1.2719251View Description Hide Description
Energy levels and hyperfine structure constants have been compiled for the sixteen longest lived isotopes of francium. For most isotopes with atomic weights in the range 199 the only measurements made are for the and levels. Additional energy-level data are available for , , and . Wavelengths with classifications and transition probabilities are tabulated for . In addition, the ionization energy is included for isotopes for which a sufficient number of levels have been measured, and .
36(2007); http://dx.doi.org/10.1063/1.2207144View Description Hide Description
The energy levels and spectrallines of gallium atom in all stages of ionization have been compiled. Experimental data on spectrallines and energy levels exist for spectra Ga I through Ga VII, Ga XIII through Ga XXVI, and Ga XXX. For Li-like Ga XXIX through H-like Ga XXXI, theoretical data on energy levels and line wavelengths are compiled. For Ga I, Ga II, and Ga III we include radiative probabilities of electric-dipole transitions where available. For Ga XV through Ga XX, Ga XXIII through Ga XXVI, and Ga XXX, radiative probabilities of magnetic-dipole and electric-quadrupole transitions are included. The ground state configuration and term and a value of ionization energy are included for each ion.
36(2007); http://dx.doi.org/10.1063/1.2716004View Description Hide Description
An innovative method for the regression of thermodynamic properties of pure fluids was recently proposed. The technique, indicated as an extended equation of state, adopts a framework similar to the extended corresponding states method, but a cubic equation is assumed instead of the equation of state of the reference fluid and the shape functions are expressed through a multilayer feedforward neural network. The use of a neural network assures a very high flexibility of the functional form to be regressed, so the resulting model reaches a representation accuracy which is comparable to that attained by the state-of-the-art multiparameter equations of state in the representation of the thermodynamic properties of a pure fluid. The technique was applied here to sulfur hexafluoride aiming at drawing its dedicated equation of state in a heuristic mode directly from the available experimental data. For sulfur hexafluoride (critical point is at and ), experimental data of several properties in homogeneous states and of properties at phase equilibrium are available. The data approximately cover the range from the triple-point temperature at and for pressures up to . The regression procedure was developed on a subset of well distributed density and vapor–liquid coexistence data, the so-called “training set,” and the model was successively validated for all the data sets, including the literature sources reporting values of isobaric heat capacity,speed of sound, and Joule–Thomson coefficient. The obtained results are satisfactory; in fact the proposed equation of state represents the available data within their experimental accuracy.
Thermochemistry of Oxabicyclo-Heptanes, Oxabicyclo-Heptene: Enthalpy of Formation, Entropy, Heat Capacity, and Group Additivity36(2007); http://dx.doi.org/10.1063/1.2734558View Description Hide Description
Thermochemical properties, , and of the seven target bicyclic epoxides are calculated using the density functional methods. Molecular structures and vibration frequencies for 6-oxabicyclo[3.1.0]hexane, 7-oxabicyclo[4.1.0]heptane, 8-oxabicyclo[5.1.0]octane, 7-oxabicyclo[2.2.1]heptane, endo-2-methyl-7-oxabicyclo[2.2.1]heptane, exo-2-methyl-7-oxabicyclo[2.2.1]heptane and 7-oxabicyclo[4.1.0]hept-2,4-ene are calculated at the level of theory. Enthalpies of formation are determined at calculation level using isodesmic and homodesmic working reactions with the and known enthalpies of reference species in each of three different work reactions. Entropy (298) and heat capacity values along with Benson Group additivity parameters are reported for each ring system. Data previously reported on oxybicyclo-epoxides are summarized.