Showing papers in "Journal of Physical and Chemical Reference Data in 2002"

The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use

Abstract: In 1995, the International Association for the Properties of Water and Steam (IAPWS) adopted a new formulation called “The IAPWS Formulation 1995 for the Thermodynamic Properties of Ordinary Water Substance for General and Scientific Use”, which we abbreviate to IAPWS-95 formulation or IAPWS-95 for short. This IAPWS-95 formulation replaces the previous formulation adopted in 1984. This work provides information on the selected experimental data of the thermodynamic properties of water used to develop the new formulation, but information is also given on newer data. The article presents all details of the IAPWS-95 formulation, which is in the form of a fundamental equation explicit in the Helmholtz free energy. The function for the residual part of the Helmholtz free energy was fitted to selected data for the following properties: (a) thermal properties of the single-phase region (pρT) and of the vapor–liquid phase boundary (pσρ′ρ″T), including the phase-equilibrium condition (Maxwell criterion), and (b) t...

Thermodynamic Quantities for the Ionization Reactions of Buffers

Abstract: This review contains selected values of thermodynamic quantities for the aqueous ionization reactions of 64 buffers, many of which are used in biological research. Since the aim is to be able to predict values of the ionization constant at temperatures not too far from ambient, the thermodynamic quantities which are tabulated are the pK, standard molar Gibbs energy ΔrG∘, standard molar enthalpy ΔrH°, and standard molar heat capacity change ΔrCp∘ for each of the ionization reactions at the temperature T=298.15 K and the pressure p=0.1 MPa. The standard state is the hypothetical ideal solution of unit molality. The chemical name(s) and CAS registry number, structure, empirical formula, and molecular weight are given for each buffer considered herein. The selection of the values of the thermodynamic quantities for each buffer is discussed.

Enthalpies of Sublimation of Organic and Organometallic Compounds. 1910–2001

Abstract: A compendium of sublimation enthalpies, published within the period 1910–2001 (over 1200 references), is reported. A brief review of the temperature adjustments for the sublimation enthalpies from the temperature of measurement to the standard reference temperature, 298.15 K, is included, as are recently suggested values for several reference materials. Sublimation enthalpies are included for organic, organometallic, and a few inorganic compounds.

Experimental Stark Widths and Shifts for Spectral Lines of Neutral and Ionized Atoms (A Critical Review of Selected Data for the Period 1989 Through 2000)

Abstract: A critical review of the available experimental data on Stark widths and shifts for spectral lines of nonhydrogenic neutral atoms and positive ions has been carried out. The review covers the period from 1989 through the end of 2000 and represents a continuation of earlier critical reviews up to 1988. Data tables containing the selected experimental Stark broadening parameters are presented with estimated accuracies. Guidelines for the accuracy estimates, developed during the previous reviews, are summarized again. The data are arranged according to elements and spectra, and these are presented in alphabetical and numerical order, respectively. A total of 77 spectra are covered, and the material on multiply charged ions has significantly increased. Comparisons with comprehensive calculations based on semiclassical theory are made whenever possible, since the comparison with theory has often been a principal motivation for the experiments.

Refractive Index and Dispersion of Fluorides and Oxides

Abstract: The refractive indices of 509 oxides and 55 fluorides were analyzed using two forms of a one-term Sellmeier equation: (1) 1/(n2−1)=−A/λ2+B, where A, the slope of the plot of (n2−1)−1 versus λ−2 in units of 10−16 m2, gives a measure of dispersion and B, the intercept of the plot at λ=∞, gives n∞=(1+1/B)1/2 and (2) n2−1=EdEo/(Eo2−(ℏω)2), where ℏω=the photon energy, Eo=the average single oscillator (Sellmeier) energy gap, and Ed=the average oscillator strength, which measures the strength of interband optical transitions. Form (1) was used to calculate n at λ=589.3 nm (nD) and n at λ=∞ (n∞), and the dispersion constant A. The total mean polarizabilility for each compound was calculated using the Lorenz–Lorentz equation: αe=3/4π [(Vm) (n∞2−1)/(n∞2+2)], where Vm is the molar volume in A3. Provided for each compound are: nD, n∞, Vm, 〈αe〉, 〈A〉, 〈B〉, 〈Ed〉, 〈Eo〉, the literature reference, the method of measurement of n and estimated errors in n. Results obtained by prism, infrared reflectivity, ellipsometry, and i...

Cross Sections for Electron Collisions with Carbon Monoxide

Abstract: Cross section data are collected and reviewed for electron collisions with carbon monoxide. Collision processes included are total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational and electronic states, ionization, and dissociation. For each process, recommended values of the cross sections are presented, when possible. The literature has been surveyed through to the end of 2013.

Evaluated Enthalpies of Formation of the Stable Closed Shell C1 and C2 Chlorinated Hydrocarbons

Abstract: Experimental data on the enthalpies of formation of chloromethanes, chloroethynes, chloroethenes, and chloroethanes are critically reviewed. Enthalpy of formation values for the C1 and C2 chlorinated hydrocarbons are highly cross-linked by various measured reaction equilibria and currently available sets of values are not internally self-consistent. It is shown that the early static bomb combustion calorimetry studies on highly chlorinated compounds generally give enthalpies of formation that are systematically more positive than later values derivable from rotating bomb combustion or equilibria studies. Those previously recommended values which were based mainly on the early static bomb work therefore need substantial revision. On the basis of more recent literature data obtained with rotating bomb combustion calorimetry, together with analyses of literature data on other reaction enthalpies and equilibria involving chlorinated hydrocarbons, an updated self-consistent set of ΔfHo[298.15 K] values for clo...

Critically Evaluated Atomic Transition Probabilities for Ba I and Ba II

Abstract: Atomic transition probabilities for allowed and forbidden lines of Ba I and Ba II are tabulated, based on a critical evaluation of recent literature sources. The data are presented in multiplet format and are ordered by increasing excitation energies.

pVT–Second Virial Coefficients B(T ), Viscosity η(T ), and Self-Diffusion ρD(T) of the Gases: BF3, CF4, SiF4, CCl4, SiCl4, SF6, MoF6, WF6, UF6, C(CH3)4, and Si(CH3)4 Determined by Means of an Isotropic Temperature-Dependent Potential

Abstract: We present results on self-consistent calculations of second pVT–virial coefficients B(T), viscosity data η(T), and diffusion coefficients ρD(T) for eleven heavy globular gases: boron trifluoride (BF3), carbon tetrafluoride (CF4), silicon tetrafluoride (SiF4), carbon tetrachloride (CCl4), silicon tetrachloride (SiCl4), sulfur hexafluoride (SF6), molybdenum hexafluoride (MoF6), tungsten hexafluoride (WF6), uranium hexafluoride (UF6), tetramethyl methane (C(CH3)4, TMM), and tetramethyl silane (Si(CH3)4, TMS). The calculations are performed mainly in the temperature range between 200 and 900 K by means of isotropic n−6 potentials with temperature-dependent separation rm(T) and potential well depth e(T). The potential parameters at T=0 K (e, rm, n) and the enlargement of the first level radii δ are obtained solving an ill-posed problem of minimizing the squared deviations between experimental and calculated values normalized to their relative experimental error. The temperature dependence of the potential is ...

IUPAC-NIST Solubility Data Series. 78. Acetonitrile Binary Systems

Abstract: The mutual solubilities and liquid–liquid equilibria of acetonitrile binary systems with different compounds exhaustively and critically are reviewed. The compounds include water, inorganic compounds, and a variety of organic compounds (hydrocarbons, halogenated hydrocarbons, alcohols, carboxylic acids and esters, nitrogen, and sulfur compounds). A total of 353 systems reported in the primary literature through 2000 are compiled. For 25 systems sufficient data are available to allow critical evaluation. All data are expressed as mass and mole fractions as well as the originally reported units. Similar reviews of gas, liquid, and solid solubilities for other systems are published in the of Solubility Data Series. This is the 78th volume of this series.

Correlation for the Vapor Pressure of Heavy Water From the Triple Point to the Critical Point

Abstract: A new formulation has been developed to represent the vapor pressure of heavy water (D2O) from its triple point to its critical point. This work takes advantage of several developments since the publication of the best previous formulation: the availability of some new data in the lower part of the temperature range, the adoption of the ITS-90 temperature scale, and the adoption of recommended values for the critical constants by the International Association for the Properties of Water and Steam (IAPWS). The new formulation fits the available data within their scatter across the entire temperature range, and is constrained to pass through the values recommended by IAPWS for the critical point. The previous formulation can be made to provide a similarly good fit if its input temperatures are converted from ITS-90 to IPTS-68 before the vapor pressure is computed. The new formulation offers the advantage of computation without having to perform a temperature conversion.

Recommended Vapor-Liquid Equilibrium Data. Part 4. Binary Alkanol-Alkene/Alkyne Systems

Abstract: The recommended vapor–liquid equilibrium (VLE) data for 39 binary n-alcohol–n-alkane systems have been obtained after critical evaluation of all data (490 data sets) reported in the open literature up to the middle of 2001. 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 the local compositions concept as well as with the equation of state appended with a chemical term (EoSC) proposed by Goral. The recommended data 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.

IUPAC-NIST Solubility Data Series. 77. C2+ Nitroalkanes With Water or Organic Solvents: Binary and Multicomponent Systems

Abstract: The mutual solubilities and liquid-liquid equilibria of binary and multicomponent systems composed of C2+ nitroalkanes with solvents are reviewed. The solvents (mainly in liquid phase) include water, inorganic compounds and a variety of organic compounds such as hydrocarbons, halogenated hydrocarbons, alcohols, acids, esters, and nitrogen compounds. A total 81 binary, 21 ternary, 2 quaternary and 1 five component systems whose properties were described in the chemical literature through 1998 are compiled. For 14 systems sufficient data were available to allow critical evaluation. All data are expressed as mass and mole fractions as well as the originally reported units. Similar reviews of gas, liquid and solid solubilities for other systems have been within the Solubility Data Series. This is volume 77 of this series.

Quasiclassical Rate Coefficients for the H2+H2 Reaction and Dissociation

Abstract: Vibrational state-to-state quasiclassical rate coefficients of the H2+H2 reaction summed over product rotational states for thermalized reactants’ rotations and translations are given at various values of the temperature in the range 1000–4000 K. Values are given for both reactive and nonreactive processes. Separate values are also given for processes involving dissociation.

Electron Interactions With BCl3

Abstract: In this paper we review and assess the cross sections for collisions of low-energy electrons with boron trichloride (BCl3). The only available experimental cross section data are for partial and total ionization and electron attachment, and the electron attachment cross sections are uncertain. Calculated values are available for the total elastic, differential elastic, and momentum transfer cross sections, and derived cross sections have been published for vibrational excitation and dissociation. Other than some rather uncertain data on electron attachment rate constants and some measurements of electron drift velocities in BCl3/Ar and BCl3/He mixtures, there are no measurements of the electron attachment, ionization, or transport coefficients for this gas. Analysis of the experimental data on the electron affinity, electron attachment, and electron scattering, enabled identification of negative ion states of BCl3 at about −0.3, 1.0, 2.8, 5.2, 7.6, and 9.0 eV. Because the existing electron collision data ...

Doppler Broadening and its Contribution to Compton Energy-Absorption Cross Sections: An Analysis of the Compton Component in Terms of Mass-Energy Absorption Coefficient

Abstract: Compton energy absorption cross sections are calculated using the formulas based on a relativistic impulse approximation to assess the contribution of Doppler broadening and to examine the Compton profile literature and explore what, if any, effect our knowledge of this line broadening has on the Compton component in terms of mass–energy absorption coefficient. Compton energy-absorption cross sections are evaluated for all elements, Z=1–100, and for photon energies 1 keV–100 MeV. Using these cross sections, the Compton component of the mass–energy absorption coefficient is derived in the energy region from 1 keV to 1 MeV for all the elements Z=1–100. The electron momentum prior to the scattering event should cause a Doppler broadening of the Compton line. The momentum resolution function is evaluated in terms of incident and scattered photon energy and scattering angle. The overall momentum resolution of each contribution is estimated for x-ray and γ-ray energies of experimental interest in the angular re...