Volume 33, Issue 3, September 2004
Index of content:
Doppler Broadening Calculations of Compton Scattering for Molecules, Plastics, Tissues, and Few Biological Materials in the X-Ray Region: An Analysis in Terms of Compton Broadening and Geometrical Energy Broadening33(2004); http://dx.doi.org/10.1063/1.1614814View Description Hide Description
Relativistic and nonrelativistic Compton profile cross sections for H, C, N, O, P, and Ca and for a few important biological materials such as water, polyethylene, lucite, polystyrene, nylon, polycarbonate, bakelite, fat, bone and calcium hydroxyapatite are estimated for a number of x-ray energies and for 59.54 keV (Am-241) γ photons. Energy broadening and geometrical broadening is estimated by assuming and are symmetrically situated around FWHM of and FWHM of Compton energy broadening are evaluated at various incident photon energies. These values are estimated around the centroid of the Compton profile with an energy interval of 0.1 and 1.0 keV for 59.54 keV photons. Total Compton, individual shell, and Compton energy–absorption scattering cross sections are evaluated in the energy region from 0.005 to 0.5 MeV. It is an attempt to know the effect of Doppler broadening for single atoms, many of which constitute the biological materials.
Use of Semiempirical Methods for Detecting Anomalies in Reported Enthalpies of Formation of Organic Compounds33(2004); http://dx.doi.org/10.1063/1.1643403View Description Hide Description
Using semiempirical methods, a survey of the enthalpies of formation of ∼1300 compounds in the NIST Chemistry WebBook database was performed and compared to the reported values. Five sets of compounds were identified: a large set in which theory and experiment agreed, a set in which they disagreed strongly due to transcription errors, a set in which they disagreed strongly due to experimental errors, a set that disagreed strongly due to errors in the method, and a set in which the difference between calculation and experiment was not obvious.
33(2004); http://dx.doi.org/10.1063/1.1643404View Description Hide Description
Energy levels, wavelengths, and transition probabilities for the first and second spectra of barium, Ba I and Ba II, have been compiled. Wavelengths of observed transitions and energy levels derived from those wavelengths have been obtained from a critical evaluation of the available literature. Measured and calculated transition probabilities for some of the observed transitions have been obtained from the recent compilation of Klose et al. [J. Z. Klose et al., J. Phys. Chem. Ref. Data 31, 217 (2002)].
Critical Evaluation of Rate Constants and Equilibrium Constants of Hydrogen Peroxide Photolysis in Acidic Aqueous Solutions Containing Chloride Ions33(2004); http://dx.doi.org/10.1063/1.1695414View Description Hide Description
Equilibrium constants and rate constants involving and determined at in the aqueous phase are updated and evaluated. Most of the rate constants and equilibrium constants are obtained by either pulse radiolysis or laser flash photolysis. The recommended values of rate constants and equilibrium constants are achieved by un-weighted averaging of the reliable experimental measurements.
33(2004); http://dx.doi.org/10.1063/1.1649348View Description Hide Description
The energy levels and observed spectral lines of the xenon atom, in all stages of ionization for which experimental data are available, have been compiled. Sufficient data were found to generate level and line tables for Xe I–Xe XI, Xe XIX, Xe XXV–Xe XXIX, Xe XLIII–Xe XLV, and Xe LI–Xe LIV. For Xe LIII and Xe LIV theoretical values are compiled for the energy levels. In 15 of the other stages a few lines are reported. Experimental g factors are included for Xe I, Xe II, and Xe III. A value, either experimental, semiempirical, or theoretical, is included for the ionization energy of each ion.
33(2004); http://dx.doi.org/10.1063/1.1638781View Description Hide Description
The spectroscopic and thermodynamic properties of the four diatomic hydrogen halide molecules—HX(g), where Cl, Br, and I—have been reviewed. Four revised thermochemical tables result from this critical review. The revisions involved the consideration of new spectroscopic information and the use of a direct summation over states for the generation of the thermochemical tables. Compared to previous calculations, the entropies at 298.15 K are unchanged, but the high temperature values are significantly different.
33(2004); http://dx.doi.org/10.1063/1.1760761View Description Hide Description
The recommended vapor–liquid equilibrium (VLE) data for mixtures of alkanols with benzene and alkylbenzenes have been selected after critical evaluation of all data reported in the open literature up to the middle of 2002. The evaluation procedure consisted in combining the thermodynamic consistency tests, data correlation, comparison with enthalpy of mixing data, and comparison of VLE data for various mixtures. The data were correlated with equations based on local compositions concept as well as with equation of state appended with chemical term (EoSC) proposed by Góral. The recommended data for 29 systems are presented in the form of individual pages containing tables of data, figures and auxiliary information. Each page corresponds to one system and contains three isotherms (spaced by at least 15 K) and one isobar (preferably at 101.32 kPa). Experimental gaps were completed with the predicted data.