Showing papers in "Journal of Physical and Chemical Reference Data in 2021"
TL;DR: In this paper, the octanol-air partition ratio (KOA) is defined as the ratio of the partition coefficient of an octanol mixture with respect to a gas component.
Abstract: Equilibrium partition coefficients or partition ratios are a fundamental concept in physical chemistry, with wide applications in environmental chemistry. While comprehensive data compilations for the octanol–water partition ratio and the Henry’s law constant have existed for many years, no comparable effort for the octanol–air partition ratio (KOA) exists. Considering the increasing use of KOA in understanding a chemical’s partitioning between a wide variety of organic phases (organic phases in atmospheric particles, plant foliage, polymeric sorbents, soil organic matter, animal tissues, etc.) and the gas phase, we have compiled all KOA values reported in the published literature. The dataset includes more than 2500 experimentally derived values and more than 10 000 estimated values for KOA, in total covering over 1500 distinct molecules. The range of measured log10 KOA values extends from −2 to 13. Many more measured values have been reported in the log10 KOA range from 2 to 5 and from 6 to 11 compared to the range from 5 to 6, which is due to the complementary applicability range of static and dynamic measurement techniques. The compilation also identifies measured data that are judged not reliable. KOA values for substances capable of undergoing strong hydrogen bonding derived from regressions with retention times on nonpolar gas chromatographic columns deviate strongly from values estimated by prediction techniques that account for such intermolecular interactions and should be considered suspect. It is hoped that the database will serve as a source for locating existing KOA data and for the calibration and evaluation of new KOA prediction techniques.
21 citations
TL;DR: The literature has been surveyed up to the end of 2019 as mentioned in this paper, and the recommended values of the cross sections are presented for each of these processes, the recommended value for each process are presented.
Abstract: Electron collision cross section data for the water molecule are compiled from the literature. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, electronic excitation, dissociation, ionization, and dissociative attachment. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed up to the end of 2019.
21 citations
TL;DR: In this paper, the authors presented new equations of state for the binary mixtures H2 + CH4, H2+ N2, H 2 + CO2, and H 2+ CO 2 for describing hydrogen-rich multicomponent mixtures.
Abstract: New equations of state for the binary mixtures H2 + CH4, H2 + N2, H2 + CO2, and H2 + CO are presented. The results are part of an ongoing research project aiming at an improvement of the GERG-2008 model for the description of hydrogen-rich multicomponent mixtures. The equations are formulated in terms of the reduced Helmholtz energy and allow for the calculation of all thermodynamic properties over the entire fluid surface including the gas phase, liquid phase, supercritical region, and equilibrium states. The mathematical structure of the new mixture models corresponds to the form chosen for the reference model GERG-2008 of Kunz and Wagner [J. Chem. Eng. Data 57, 3032 (2012)]. In this way, the equations can be implemented into the existing framework of the GERG-2008 model. The ranges of validity of the new equations correspond to the normal and extended ranges of validity of the GERG-2008 model.
15 citations
TL;DR: In this article, the current data situation in the field is reviewed, encompassing the latest developments and remaining challenges, in order to suggest possible approaches for reducing RIGM uncertainties and improving the performance of existing RIMM applications.
Abstract: The redefinition of the kelvin has increased focus on thermometry techniques that use the newly fixed value of the Boltzmann constant to realize thermodynamic temperature. One such technique that has advanced considerably in recent years is refractive-index gas thermometry. Generalized as refractive-index gas metrology (RIGM), this also includes a range of applications outside of temperature realizations, such as pressure standards and measurements of the physical properties of gases. Here, the current data situation in the field is reviewed, encompassing the latest developments and remaining challenges, in order to suggest possible approaches for reducing RIGM uncertainties and improving RIGM applications. New analyses of existing experimental literature data are presented for the second density virial coefficient Bρ of helium, neon, argon, and nitrogen; the third density virial coefficient Cρ of nitrogen; and the third dielectric virial coefficient Ce of helium, neon, and argon. A need is identified for more accurate reference-quality datasets to be measured or calculated in several areas, with robust uncertainty budgets, to support future RIGM advancements. The most urgent of these are the bulk modulus of copper; thermodynamic accuracy of the International Temperature Scale of 1990; molar optical refractivity AR of neon, argon, and nitrogen; diamagnetic susceptibility χ0 of neon and argon; second density virial coefficient Bρ of argon; third dielectric virial coefficient Ce of helium, neon, and argon; and third optical refractivity virial coefficient CR of helium and neon.
12 citations
TL;DR: In this paper, the authors evaluated rate constants from the literature for abstraction of H from the homologous series consisting of the fluoromethanes (CH3F, CH2F2, and CHF3) and methane (CH4) by the radicals H atom, O atom, OH, and F atom.
Abstract: In this work, we compiled and critically evaluated rate constants from the literature for abstraction of H from the homologous series consisting of the fluoromethanes (CH3F, CH2F2, and CHF3) and methane (CH4) by the radicals H atom, O atom, OH, and F atom. These reactions have the form RH + X → R + HX. Rate expressions for these reactions are provided over a wide range of temperatures (300–1800 K). Expanded uncertainty factors f (2σ) are provided at both low and high temperatures. We attempted to provide rate constants that were self-consistent within the series—evaluating the system, not just individual reactions. For many of the reactions, the rate constants in the literature are available only over a limited temperature range (or there are no reliable measurements). In these cases, we predicted the rate constants in a self-consistent manner employing relative rates for other reactions in the homologous series using empirical structure–activity relationships, used empirical correlations between rate constants at room temperature and activation energies at high temperatures, and used relative rates derived from ab initio quantum chemical calculations to assist in rate constant predictions.
11 citations
TL;DR: The International Association for the Properties of Water and Steam has recently adopted a new formulation for the thermodynamic properties of heavy water as discussed by the authors, which is consistent with the new equation of state and is valid for fluid states up to 775 K and 960 MPa.
Abstract: The International Association for the Properties of Water and Steam has recently adopted a new formulation for the thermodynamic properties of heavy water. This manuscript describes the development of a new formulation for the viscosity of heavy water that is consistent with the new equation of state and is valid for fluid states up to 775 K and 960 MPa with uncertainties ranging from 1% to 5% depending on the state point. Comparisons with experimental data and with a previous viscosity formulation are presented. The new formulation contains terms for the enhancement of viscosity in a small region near the critical point that were not included in previous formulations. The new formulation is applicable over a wider range of conditions than previous correlations.
8 citations
TL;DR: In this paper, the surface tension of n-alkanes is considered and the Guggenheim-Katayama model is fitted to the data and values available for each fluid.
Abstract: In previous papers, specific correlations were proposed to reproduce the surface tension values selected for several families of fluids and for wide ranges of temperatures. In this paper, the surface tension of n-alkanes is considered. For that, the data available in DIPPR and DETHERM databases and in Wohlfarth and Wohlfarth [“Surface tension of pure liquids and binary liquid mixtures,” in Landolt-Bornstein, New Series Group IV Physical Chemistry Vol. 16, edited by M. D. Lechner (Springer-Verlag, Berlin, 1997)] and its updated supplements (2008 and 2016) have been compiled. In most cases, a significant number of new data have been added, which were published elsewhere during the last few years and that were not included in the previously mentioned sources. All the data and values available for each fluid have been carefully screened and subsequently fitted to the Guggenheim–Katayama model, which includes two to six adjustable coefficients for each fluid. As a result, recommended correlations for 33 n-alkanes are proposed, providing absolute deviations below 1.65 mN/m and mean absolute percentage deviations below 2.1%.
8 citations
TL;DR: In this paper, a fundamental equation of state for propylene glycol was developed, which is written in terms of the Helmholtz energy with the independent variables temperature and density.
Abstract: A fundamental equation of state was developed for propylene glycol. It is written in terms of the Helmholtz energy with the independent variables temperature and density. Due to its fundamental nature, it can be used to calculate all thermodynamic state properties from the Helmholtz energy and its derivatives with respect to the independent variables. Special attention was paid not only to accurately reproduce the available experimental data but also to correct extrapolation. Therefore, this equation can be used for application in mixture models. For the development of the present equation of state, the available literature data were supplemented with new experimental speed-of-sound measurements, which were conducted in the temperature range from 293.2 K to 353.2 K with pressures up to 20 MPa. High accuracy was achieved by applying the well-established double-path-length pulse-echo technique and a careful sample preparation.
7 citations
7 citations
TL;DR: In this article, the authors report, over an extended energy range, recommended angle-integrated cross sections for elastic scattering, discrete inelastic scattering processes, and the total ionization cross section for electron scattering from atomic indium.
Abstract: We report, over an extended energy range, recommended angle-integrated cross sections for elastic scattering, discrete inelastic scattering processes, and the total ionization cross section for electron scattering from atomic indium. In addition, from those angle-integrated cross sections, a grand total cross section is subsequently derived. To construct those recommended cross-section databases, results from original B-spline R-matrix, relativistic convergent close-coupling, and relativistic optical-potential computations are also presented here. Electron transport coefficients are subsequently calculated, using our recommended database, for reduced electric fields ranging from 0.01 Td to 10 000 Td using a multiterm solution of Boltzmann’s equation. To facilitate those simulations, a recommended elastic momentum transfer cross-section set is also constructed and presented here.
6 citations
TL;DR: In this paper, the rotational quantum-level structure of both nuclear-spin isomers of H218O is established with an average accuracy of 2.5 kHz using a variant of frequency-comb-assisted Lamb-dip saturation-spectroscopy techniques.
Abstract: Taking advantage of the extreme absolute accuracy, sensitivity, and resolution of noise-immune-cavity-enhanced optical-heterodyne-molecular spectroscopy (NICE-OHMS), a variant of frequency-comb-assisted Lamb-dip saturation-spectroscopy techniques, the rotational quantum-level structure of both nuclear-spin isomers of H218O is established with an average accuracy of 2.5 kHz. Altogether, 195 carefully selected rovibrational transitions are probed. The ultrahigh sensitivity of NICE-OHMS permits the observation of lines with room-temperature absorption intensities as low as 10−27 cm molecule−1, while the superb resolution enables the detection of a doublet with a separation of only 286(17) kHz. While the NICE-OHMS experiments are performed in the near-infrared window of 7000–7350 cm−1, the lines observed allow the determination of all the pure rotational energies of H218O corresponding to J values up to 8, where J is the total rotational quantum number. Both network and quantum theory have been employed to facilitate the measurement campaign and the full exploitation of the lines resolved. For example, to minimize the experimental effort, the transitions targeted for observation were selected via the spectroscopic-network-assisted precision spectroscopy (SNAPS) scheme built upon the extended Ritz principle, the theory of spectroscopic networks, and an underlying dataset of quantum chemical origin. To ensure the overall connection of the ultraprecise rovibrational lines for both nuclear-spin isomers of H218O, the NICE-OHMS transitions are augmented with six accurate microwave lines taken from the literature. To produce absolute ortho-H218O energies, the lowest ortho energy is determined to be 23.754 904 61(19) cm−1. A reference, benchmark-quality line list of 1546 transitions, deduced from the ultrahigh-accuracy energy values determined in this study, provides calibration standards for future high-resolution spectroscopic experiments between 0–1250 and 5900–8380 cm−1.
TL;DR: In this article, the authors review and comparatively analyzes methods and results achieved so far in the field of laser-based primary thermometry, also including spectroscopic approaches that leverage the temperature-dependent distribution of line intensities and related absorbances across the rovibrational band of a molecular sample.
Abstract: Laser-based primary thermometry was initiated almost 15 years ago by the proposal to determine the absolute temperature of a gas at thermodynamic equilibrium through the Doppler width of an associated absorption transition, exploiting the potentially very accurate measurement of an optical frequency to infer the elusive thermal energy of a molecular or atomic absorber. This approach, commonly referred to as Doppler broadening thermometry, has benefited across the years from substantial improvements, of both technical and fundamental nature, eventually reaching an accuracy of about 10 ppm on the temperature determination in the best cases. This is sufficient for Doppler broadening thermometry to play a significant role in the practical realization of the new kelvin, which follows the 2019’s redefinition from a fixed value of the Boltzmann constant, and to tackle the challenge, among others, to quantify and possibly fix systematic uncertainties of the international temperature scale of 1990. This paper reviews and comparatively analyzes methods and results achieved so far in the field of laser-based primary thermometry, also including spectroscopic approaches that leverage the temperature-dependent distribution of line intensities and related absorbances across the rovibrational band of a molecular sample. Although at an early stage of development, these approaches show a promising degree of robustness with respect to the choice of the line-shape model adopted for the fitting of the absorption spectra, which is a delicate aspect for all laser-based thermometers. We conclude by identifying possible technical and scientific evolution axes of the current scenario.
TL;DR: In this article, surface tension values for 80 esters have been compiled from databases, books, and papers in the literature, and the final dataset for each fluid has been fitted as a function of the temperature by using the Guggenheim-Katayama model.
Abstract: Surface tension values for 80 esters have been compiled from databases, books, and papers in the literature. The data have been carefully screened and selected, and the final dataset for each fluid has been fitted as a function of the temperature by using the Guggenheim–Katayama model, which requires two or four adjustable coefficients for each fluid. As a result, recommended correlations are proposed for each of the 80 esters, providing mean absolute deviations below 0.55 mN/m, mean absolute percentage deviations below 2.2%, and percentage deviations below 10% except for 3 data out of 1846 selected. These correlations are added to the collection of those previously proposed for different kinds of fluids, including common fluids, alcohols, refrigerants, organic acids, and n-alkanes.
TL;DR: In this article, the authors developed equations of state for three hexane isomers, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimmethylbutane based on experimental thermodynamic property data from the literature.
Abstract: Equations of state for three hexane isomers, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane, have been developed based on experimental thermodynamic property data from the literature. These equations are explicit in the Helmholtz energy with independent variables of temperature and density. The temperature, pressure, and density validity ranges of the equations of state were determined by the available measured data for these three fluids. The uncertainties in densities, vapor pressures, saturated liquid and vapor densities, and caloric properties were estimated by comparisons with experimental data of these properties. The behavior of various thermodynamic properties was analyzed to assess the quality of the equations of state. Physically correct behavior within the region of validity and at extremely high temperatures and pressures, and temperatures far below the triple-point temperature, was obtained through fitting multiple constraints of various properties.
TL;DR: In this article, a new fundamental equation of state (EOS) based on Helmholtz energy was developed for solid phase I of benzene, which is able to calculate all thermodynamic properties of solid benzene at temperatures up to 470 K and at pressures up to 1800 MPa.
Abstract: The thermodynamic property data for solid phase I of benzene are reviewed and utilized to develop a new fundamental equation of state (EOS) based on Helmholtz energy, following the methodology used for solid phase I of CO2 by Trusler [J. Phys. Chem. Ref. Data 40, 043105 (2011)]. With temperature and molar volume as independent variables, the EOS is able to calculate all thermodynamic properties of solid benzene at temperatures up to 470 K and at pressures up to 1800 MPa. The model is constructed using the quasi-harmonic approximation, incorporating a Debye oscillator distribution for the vibrons, four discrete modes for the librons, and a further 30 distinct modes for the internal vibrations of the benzene molecule. An anharmonic term is used to account for inevitable deviations from the quasi-harmonic model, which are particularly important near the triple point. The new EOS is able to describe the available experimental data to a level comparable with the likely experimental uncertainties. The estimated relative standard uncertainties of the EOS are 0.2% and 1.5% for molar volume on the sublimation curve and in the compressed solid region, respectively; 8%–1% for isobaric heat capacity on the sublimation curve between 4 K and 278 K; 4% for thermal expansivity; 1% for isentropic bulk modulus; 1% for enthalpy of sublimation and melting; and 3% and 4% for the computed sublimation and melting pressures, respectively. The EOS behaves in a physically reasonable manner at temperatures approaching absolute zero and also at very high pressures.
TL;DR: In this article, the authors apply optical potential and relativistic optical potential models to positron scattering from gas-phase zinc (Zn) and cadmium (Cd) gases.
Abstract: Results from the application of our optical potential and relativistic optical potential models to positron scattering from gas-phase zinc (Zn) and cadmium (Cd) are presented. In particular, integral cross sections (ICSs) for elastic scattering, positronium formation, summed discrete electronic-state excitation, and ionization scattering processes are reported for both species and over an extended incident positron energy range. From those ICSs, the total cross section is subsequently constructed by taking their sum. We note that there are currently no experimental data available for any of these scattering processes for either species, with earlier computational results being limited to the elastic channel and restricted to relatively narrow incident positron energy regimes. Nonetheless, we construct recommended positron cross section datasets for both zinc and cadmium over the incident positron energy range of 0–10 000 eV. The recommended positron cross section data are subsequently employed in a multi-term Boltzmann equation analysis to simulate the transport of positrons, under the influence of an applied (external) electric field, through the background Zn and Cd gases. Qualitatively similar behavior in the calculated transport coefficients was observed between both species. Finally, for the case of zinc, the present positron transport coefficients are compared against corresponding results from electron transport with some significant differences now being observed.
TL;DR: A brief overview of articles published in the Journal of Physical and Chemical Reference Data containing experimental thermodynamic data as well as group contribution methods used to predict thermodynamic quantities of organic compounds can be found in this article.
Abstract: A brief overview is provided on articles published in the Journal of Physical and Chemical Reference Data containing experimental thermodynamic data as well as group contribution methods used to predict thermodynamic quantities of organic compounds. Published papers have contained large compilations of experimental and calculated condensed-phase and gas-phase standard molar enthalpies of formation, isobaric molar heat capacities, molar enthalpies of fusion, molar enthalpies of sublimation, and molar enthalpies of vaporization.
TL;DR: In this paper, the authors compiled and reviewed solubility data for 15 alkanoic acids dissolved in neat organic solvents and well-defined binary organic and aqueous-organic solvent mixtures.
Abstract: Solubility data are compiled and reviewed for 15 alkanoic acids dissolved in neat organic solvents and well-defined binary organic and aqueous–organic solvent mixtures. The compiled solubility data were retrieved from the published chemical, engineering, and pharmaceutical literature covering the period between 1910 and the beginning of 2021.
TL;DR: In this paper, a wide-range equation of state (EOS) for 3He-4He mixtures based on the reduced Helmholtz free energy multi-fluid approximation model was presented.
Abstract: The work presents the first wide-range equation of state (EOS) for 3He–4He mixtures based on the reduced Helmholtz free energy multi-fluid approximation model. It covers the temperature range from 2.17 to 300 K and the pressure from the vapor pressure up to 3 MPa for any given mixture 3He mole fraction. In this model, the 4He and 3He reduced Helmholtz free energy equations and departure functions from the literature are employed and only five unknown mixture parameters are needed for each given departure function. The parameters and the best model for the concerned binary mixture were determined by the Levenberg–Marquardt optimization method. With the best developed model, the liquid, gaseous, and saturated thermophysical properties of the mixture can be mostly described with an accuracy better than 5%. Furthermore, a database for the thermophysical properties of 3He–4He mixtures is generated and provided for interpolation in temperature, pressure, and 3He mole fraction. The current EOS and database can be applied to the design and optimization of ultra-low temperature refrigerators.