Jump to Content
View Cart
Top 20 Most Read Articles
September 2008
The 20 articles with the most full-text downloads during the month, in descending order.
 |
CODATA recommended values of the fundamental physical constants: 2006 J. Phys. Chem. Ref. Data 37, 1187 (2008); http://dx.doi.org/10.1063/1.2844785 (98 pages) Online Publication Date: 15 July 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
This paper gives the 2006 self-consistent set of values of the basic constants and conversion factors of physics and chemistry recommended by the Committee on Data for Science and Technology (CODATA) for international use. Further, it describes in detail the adjustment of the values of the constants, including the selection of the final set of input data based on the results of least-squares analyses. The 2006 adjustment takes into account the data considered in the 2002 adjustment as well as the data that became available between 31 December 2002, the closing date of that adjustment, and 31 December 2006, the closing date of the new adjustment. The new data have led to a significant reduction in the uncertainties of many recommended values. The 2006 set replaces the previously recommended 2002 CODATA set and may also be found on the World Wide Web at physics.nist.gov/constants.
|
|||
|
Show PACS
|
|||
|
|
J. Phys. Chem. Ref. Data 31, 387 (2002); http://dx.doi.org/10.1063/1.1461829 (149 pages) Online Publication Date: 7 June 2002
Full Text:
|
Download PDF
|
||
|
Show 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) the caloric properties specific isochoric heat capacity, specific isobaric heat capacity, speed of sound, differences in the specific enthalpy and in the specific internal energy, Joule–Thomson coefficient, and isothermal throttling coefficient. By applying modern strategies for optimizing the functional form of the equation of state and for the simultaneous nonlinear fitting to the data of all mentioned properties, the resulting IAPWS-95 formulation covers a validity range for temperatures from the melting line (lowest temperature 251.2 K at 209.9 MPa) to 1273 K and pressures up to 1000 MPa. In this entire range of validity, IAPWS-95 represents even the most accurate data to within their experimental uncertainty. In the most important part of the liquid region, the estimated uncertainty of IAPWS-95 ranges from ±0.001% to ±0.02% in density, ±0.03% to ±0.2% in speed of sound, and ±0.1% in isobaric heat capacity. In the liquid region at ambient pressure, IAPWS-95 is extremely accurate in density (uncertainty ⩽±0.0001%) and in speed of sound (±0.005%). In a large part of the gas region the estimated uncertainty in density ranges from ±0.03% to ±0.05%, in speed of sound it amounts to ±0.15% and in isobaric heat capacity it is ±0.2%. In the critical region, IAPWS-95 represents not only the thermal properties very well but also the caloric properties in a reasonable way. Special interest has been focused on the extrapolation behavior of the new formulation. At least for the basic properties such as pressure and enthalpy, IAPWS-95 can be extrapolated up to extremely high pressures and temperatures. In addition to the IAPWS-95 formulation, independent equations for vapor pressure, the densities, and the most important caloric properties along the vapor–liquid phase boundary, and for the pressure on the melting and sublimation curve, are given. Moreover, a so-called gas equation for densities up to 55 kg m−3 is also included. Tables of the thermodynamic properties calculated from the IAPWS-95 formulation are listed in the Appendix. © 2002 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Wavelengths, Transition Probabilities, and Energy Levels for the Spectra of Sodium (Na I–Na XI) J. Phys. Chem. Ref. Data 37, 1659 (2008); http://dx.doi.org/10.1063/1.2943652 (105 pages) Online Publication Date: 10 September 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Energy levels, with classifications and uncertainties, have been compiled for the spectra of the neutral atom and all positive ions of sodium (Z = 11). Wavelengths with classifications, intensities, and transition probabilities are also tabulated. In addition, ground states and ionization energies are listed. Where available, the hyperfine structure constants and the percentages of the leading components of the energy levels are included. For all ionization stages of sodium, at least some experimental data are available; however, for those for which only a few transitions have been measured, theoretical calculations or values obtained by isoelectronic fitting are reported. Similarly, theoretical or isoelectronically determined ionization energies are given when they are thought to be more accurate than the available experimental data would produce.
|
|||
|
Show PACS
|
|||
|
|
Atomic Transition Probabilities of Silicon. A Critical Compilation J. Phys. Chem. Ref. Data 37, 1285 (2008); http://dx.doi.org/10.1063/1.2734566 (217 pages) Online Publication Date: 17 July 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
This compilation is the third in a series of updates to a critical compilation published in 1969 by
Wiese et al. [Atomic Transition Probabilities, Vol. II: Sodium through Calcium, NSRDS-NBS Vol. 22 (U.S. GPO, Washington, D.C., 1969)].
Atomic transition probabilities have been critically evaluated and compiled for about 5800 spectral lines of silicon (nuclear charge Z = 14). The cited values and their estimated uncertainties are based on our consideration of all available theoretical and experimental literature sources. All ionization stages (except for hydrogenic) are covered, and the data are presented in separate tables for each atom and ion. Separate listings are given for “allowed” (electric dipole) and “forbidden” (magnetic dipole plus electric and magnetic quadrupole) transitions. In each spectrum, lines are grouped into multiplets which are arranged in order of ascending lower and upper level energies, respectively. For each line, the emission transition probability Aki, the line strength S, and (for allowed lines) the absorption oscillator strength fik are given, together with the spectroscopic designation, the wavelength, the statistical weights, and the energy levels of the lower and upper states. The estimated relative uncertainties of the line strength are also indicated, as are the source citations. We include only those lines whose transition rates are deemed sufficiently accurate to qualify as reference values. Short introductions precede the tables for each ion.
|
|||
|
Show PACS
|
|||
|
|
Handbook of Basic Atomic Spectroscopic Data J. Phys. Chem. Ref. Data 34, 1559 (2005); http://dx.doi.org/10.1063/1.1800011 (701 pages) Online Publication Date: 28 September 2005
Full Text:
|
Download PDF
|
|||||||||||||||||
|
Show Abstract
© 2005 American Institute of Physics. |
||||||||||||||||||
|
Show PACS
|
||||||||||||||||||
|
|
Physical Properties of Ionic Liquids: Database and Evaluation J. Phys. Chem. Ref. Data 35, 1475 (2006); http://dx.doi.org/10.1063/1.2204959 (43 pages) Online Publication Date: 10 October 2006
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the collected database, the structure-property relationship was evaluated. The correlation of melting points of two most common systems, disubstituted imidazolium tetrafluoroborate and disubstituted imidazolium hexafluorophosphate, was carried out using a quantitative structure-property relationship method.
|
|||
|
Show PACS
|
|||
|
|
Evaluated Kinetic Data for Combustion Modeling: Supplement II J. Phys. Chem. Ref. Data 34, 757 (2005); http://dx.doi.org/10.1063/1.1748524 (641 pages) Online Publication Date: 27 July 2005
Full Text:
|
Download PDF
|
||
|
Show Abstract
This compilation updates and expands two previous evaluations of kinetic data on elementary, homogeneous, gas phase reactions of neutral species involved in combustion systems [J. Phys. Chem. Ref Data 21, 411 (1992); 23, 847 (1994)]. The work has been carried out under the auspices of the IUPAC Commission on Chemical Kinetics and the UK Engineering and Physical Sciences Research Council. Individual data sheets are presented for most reactions but the kinetic data for reactions of C2, C, ethyl, i-propyl, t-butyl, and allyl radicals are summarized in tables. Each data sheet sets out relevant thermodynamic data, experimental kinetic data, references, recommended rate parameters with their error limits and a brief discussion of the reasons for their selection. Where appropriate the data are displayed on an Arrhenius diagram or by fall-off curves. Tables summarizing the recommended rate data and the thermodynamic data for the reactant and product species are given, and their sources referenced. As in the previous evaluations the reactions considered relate largely to the combustion in air of organic compounds containing up to three carbon atoms and simple aromatic compounds. Thus the data base has been expanded, largely by dealing with a substantial number of extra reactions within these general areas. © 2005 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
J. Phys. Chem. Ref. Data 37, 1655 (2008); http://dx.doi.org/10.1063/1.2976030 (1 page) Online Publication Date: 29 August 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Abstract Unavailable
|
|||
|
Show PACS
|
|||
|
|
J. Phys. Chem. Ref. Data 36, 1 (2007); http://dx.doi.org/10.1063/1.2360986 (18 pages) Online Publication Date: 8 February 2007
Full Text:
Read Online (HTML)
|
Download PDF
|
|||
|
Show Abstract
All the currently available experimental permittivity data for pure water are used to derive an interpolation function that precisely represents ε(ν,t,) at standard atmospheric pressure, for frequencies and temperatures in the ranges 0 ⩽ ν ⩽ 25 THz and 0 ⩽ t ⩽ 100 °C. The permittivity data is represented in terms of relaxations and resonances processes. There are three relaxations in the microwave region and two resonances in the far infrared. The temperature dependence of the relaxation and resonance parameters are determined. For example, at 25 °C the three relaxation frequencies are 18.56 GHz, 167.83 GHz, 1.944 THz and the two resonance frequencies are 4.03 and 14.48 THz.
|
||||
|
Show PACS
|
||||
|
|
Binding Energies in Atomic Negative Ions: III J. Phys. Chem. Ref. Data 28, 1511 (1999); http://dx.doi.org/10.1063/1.556047 (23 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
This article updates a 14 yr old review on this subject [J. Phys. Chem. Ref. Data 14, 731 (1985)]. A survey of the electron affinity determinations for the elements up to Z = 94 is presented, and based upon these data, a set of recommended electron affinities is established. New developments in the experimental methods which yield accurate electron binding energies are described. Fine structure splittings and excited state energies of negative ions as well as lifetimes of metastable states are given. Progress in theoretical calculations of atomic electron affinities is documented by comparison with reliable experimental data. © 1999 American Institute of Physics and American Chemical Society. |
|||
|
Show PACS
|
|||
|
|
Viscosity of concentrated sucrose and trehalose aqueous solutions including the supercooled regime J. Phys. Chem. Ref. Data 37, 1503 (2008); http://dx.doi.org/10.1063/1.2932114 (13 pages) Online Publication Date: 23 July 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
The viscosity of aqueous solutions of sucrose and trehalose is analyzed over a wide range of concentrations and temperatures covering the normal liquid and supercooled liquid regions, close to the glass transition temperature. These sugar solutions are fragile systems whose viscosity exhibits temperature dependence with a large departure from Arrhenius behavior. A description of the temperature and concentration dependences of the solution viscosity is given in terms of a scaled Arrhenius representation, which adopts the reduced temperature Tg/T as the state variable. A comparison with results obtained from other theoretical or semiempirical equations is also presented.
|
|||
|
Show PACS
|
|||
|
|
J. Phys. Chem. Ref. Data 30, 187 (2001); http://dx.doi.org/10.1063/1.1347984 (253 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
Factors affecting sorption of organic pollutants by natural sorbents (soils, sediments, clays, humic materials, and dissolved organic matters) and sorption coefficients for selected pollutants are reviewed on the basis of the literature results and interpretations; with 681 references examined. The most significant aspects of the sorption process are discussed: sorption isotherms and sorption kinetics; effects of sorbent physico-chemical characteristics (pH, cation exchange capacity, ionic strength, surface area, etc.); effect of the temperature; sorption of volatile compounds; effect of the presence of a cosolvent; association with dissolved organic matter; effect of the sorbent concentration; “hysteresis” or nonsingularity in the sorption–desorption process, and its implications in the transport of these contaminants through soil columns. The experimental and prediction methods adopted for the determination and estimation of the sorption coefficients are also described. Literature sorption coefficients for selected hydrophobic, polar, and ionizable compounds are collected. The compounds taken into consideration belong to the following classes: monoaromatic hydrocarbons, polycyclic aromatic hydrocarbons, chlorinated alkyl and aryl compounds, phenol and chlorinated phenols, polychlorobiphenyls, dioxins, and pesticides. The respective sorption coefficients (log Kd) and organic carbon-referenced sorption coefficients (log Koc) are tabulated together with the most relevant characteristics of the respective sorbent, the measurement temperature, and the experimental methods. The log Koc values are averaged and compared with other experimental and estimated literature data. Differences of sorption coefficients on soils and sediments and effect of pH on sorption coefficients for ionizable compounds are evidentiated. © 2001 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
IUPAC-NIST Solubility Data Series. 86. Ethers and Ketones with Water. Part 5. C6 Ketones with Water J. Phys. Chem. Ref. Data 37, 1575 (2008); http://dx.doi.org/10.1063/1.2950300 (35 pages) Online Publication Date: 18 August 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
The mutual solubilities and related liquid-liquid equilibria of eight binary systems of C6 ketones with water are exhaustively and critically reviewed. Reports of experimental determination of solubility that appeared in the primary literature prior to the middle of 2007 are compiled. For five 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 method based on the evaluation of all experimental data for a given series of ketones was used.
|
|||
|
Show PACS
|
|||
|
|
Vibrational and Electronic Energy Levels of Polyatomic Transient Molecules. Supplement B J. Phys. Chem. Ref. Data 32, 1 (2003); http://dx.doi.org/10.1063/1.1497629 (441 pages) Online Publication Date: 18 February 2003
Full Text:
|
Download PDF
|
||
|
Show Abstract
A summary is presented of recently published, critically evaluated experimental vibrational and electronic energy level data for approximately 1700 neutral and ionic transient molecules and high temperature species possessing from three to sixteen atoms. Although the emphasis is on species with lifetimes too short for study using conventional sampling techniques, there has been selective extension of the compilation to include data for isolated molecules of inorganic species such as the heavy-metal oxides, which are important in a wide variety of industrial chemical systems. Radiative lifetimes and the principal rotational constants are included. Observations in the gas phase, in molecular beams, and in rare-gas and diatomic molecule matrices are evaluated, and several thousand references are cited. The types of measurement surveyed include conventional and laser-based absorption and emission techniques, laser absorption with mass analysis, and photoelectron spectroscopy. © 2003 by the U.S. Secretary of Commerce on behalf of the United States. All rights reserved. |
|||
|
Show PACS
|
|||
|
|
Atomic Transition Probabilities of Aluminum. A Critical Compilation J. Phys. Chem. Ref. Data 37, 709 (2008); http://dx.doi.org/10.1063/1.2734564 (203 pages) Online Publication Date: 6 March 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
This compilation is the second in a series of updates to Atomic Transition Probabilities, Sodium through Calcium, published in 1969 by
Wiese et al. [Atomic Transition Probabilities, Vol. II, Vol. II: Sodium through Calcium, NSROS-NBS Vol. 2 (U.S. GPO, Washington, D.C., 1969)]
. Atomic transition probabilities have been critically evaluated and compiled for about 5000 spectral lines of aluminum (nuclear charge Z = 13). The cited values and their estimated uncertainties are based on our consideration of all available theoretical and experimental literature sources. All ionization stages (except for hydrogenic) are covered, and the data are presented in separate tables for each atom and ion. Separate listings are given for “allowed” (electric dipole) and “forbidden” (magnetic dipole plus electric and magnetic quadrupole) transitions. In each spectrum, lines are grouped into multiplets which are arranged in order of ascending lower- and upper-level energies, respectively. For each line, the emission transition probability Aki, the line strength S, and (for allowed lines) the absorption oscillator strength fik are given, together with the spectroscopic designation, the wavelength, the statistical weights, and the energy levels of the lower and upper states. The estimated relative uncertainties of the line strength are also indicated, as are the source citations. We include only those lines whose transition rates are deemed sufficiently accurate to qualify as reference values. Short introductions precede the tables for each ion.
|
|||
|
Show PACS
|
|||
|
|
Reference Data for the Density and Viscosity of Liquid Aluminum and Liquid Iron J. Phys. Chem. Ref. Data 35, 285 (2006); http://dx.doi.org/10.1063/1.2149380 (16 pages) Online Publication Date: 10 February 2006
Full Text:
|
Download PDF
|
|||
|
Show Abstract
The available experimental data for the density and viscosity of liquid aluminum and iron have been critically examined with the intention of establishing a density and a viscosity standard. All experimental data have been categorized into primary and secondary data according to the quality of measurement specified by a series of criteria. The proposed standard reference correlations for the density of the aluminum and iron are characterized by standard deviations of 0.65% and 0.77% at the 95% confidence level, respectively. The overall uncertainty in the absolute values of the density is estimated to be one of ±0.7% for aluminum and 0.8% for iron, which is worse than that of the most optimistic claims but recognizes the unexplained discrepancies between different methods. The standard reference correlations for the viscosity of aluminum and iron are characterized by standard deviations of 13.7% and 5.7% at the 95% confidence level, respectively. The uncertainty in the absolute values of the viscosity of the two metals is thought to be no larger than the scatter between measurements made with different techniques and so can be said to be ±14% in the case of aluminum and ±6% in the case of iron. © 2006 American Institute of Physics. |
||||
|
Show PACS
|
||||
|
|
Enthalpies of Vaporization of Organic and Organometallic Compounds, 1880–2002 J. Phys. Chem. Ref. Data 32, 519 (2003); http://dx.doi.org/10.1063/1.1529214 (360 pages) Online Publication Date: 21 April 2003
Full Text:
|
Download PDF
|
||
|
Show Abstract
A compendium of vaporization enthalpies published within the period 1910–2002 is reported. A brief review of temperature adjustments of vaporization enthalpies from temperature of measurement to the standard reference temperature, 298.15 K, is included as are recently suggested reference materials. Vaporization enthalpies are included for organic, organo-metallic, and a few inorganic compounds. This compendium is the third in a series focusing on phase change enthalpies. Previous compendia focused on fusion and sublimation enthalpies. Sufficient data are presently available for many compounds that thermodynamic cycles can be constructed to evaluate the reliability of the measurements. A protocol for doing so is described. © 2003 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
Cross Sections for Electron Collisions with Hydrogen Molecules J. Phys. Chem. Ref. Data 37, 913 (2008); http://dx.doi.org/10.1063/1.2838023 (19 pages) Online Publication Date: 31 March 2008
Full Text:
Read Online (HTML)
|
Download PDF
|
||
|
Show Abstract
Cross section data have been compiled for electron collisions with hydrogen molecules based on 71 references. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational, vibrational, and electronic states, dissociation, ionization, emission of radiation, and dissociative attachment. For each process, the recommended values of the cross section are presented for use. The literature has been surveyed through the end of 2006.
|
|||
|
Show PACS
|
|||
|
|
Transition Probabilities for Hydrogen-Like Atoms J. Phys. Chem. Ref. Data 33, 1059 (2004); http://dx.doi.org/10.1063/1.1796671 (12 pages) Online Publication Date: 5 January 2005
Full Text:
|
Download PDF
|
||
|
Show Abstract
E1, M1, E2, M2, E3, and M3 transition probabilities for hydrogen-like atoms are calculated with point-nucleus Dirac eigenfunctions for Z = 1–118 and up to large quantum numbers l = 25 and n = 26, increasing existing data more than a thousandfold. A critical evaluation of the accuracy shows a higher reliability with respect to previous works. Tables for hydrogen containing a subset of the results are given explicitly, listing the states involved in each transition, wavelength, term energies, statistical weights, transition probabilities, oscillator strengths, and line strengths. The complete results, including 1 863 574 distinct transition probabilities, lifetimes, and branching fractions are available at http://www.fisica.unam.mx/research/tables/spectra/1el © 2005 American Institute of Physics. |
|||
|
Show PACS
|
|||
|
|
J. Phys. Chem. Ref. Data 29, 167 (2000); http://dx.doi.org/10.1063/1.556058 (100 pages)
Full Text:
|
Download PDF
|
||
|
Show Abstract
This paper updates and extends part of the previous data base of critical evaluations of the kinetics and photochemistry of gas-phase chemical reactions of neutral species involved in atmospheric chemistry [J. Phys. Chem. Ref. Data 9, 295 (1980); 11, 327 (1982); 13, 1259 (1984); 18, 881 (1989); 21, 1125 (1992); 26, 521 (1997); 26, 1329 (1997); 28, 191 (1999)]. The present evaluation is limited to the inorganic halogen family of atmospherically important reactions. The work has been carried out by the authors under the auspices of the IUPAC Subcommittee on Gas Phase Kinetic Data Evaluation for Atmospheric Chemistry. Data sheets have been prepared for 102 thermal and photochemical reactions, containing summaries of the available experimental data with notes giving details of the experimental procedures. For each thermal reaction, a preferred value of the rate coefficient at 298 K is given together with a temperature dependence where possible. The selection of the preferred value is discussed and estimates of the accuracies of the rate coefficients and temperature coefficients have been made for each reaction. For each photochemical reaction the data sheets list the preferred values of the photoabsorption cross sections and the quantum yields of the photochemical reactions together with comments on how they were selected. The data sheets are intended to provide the basic physical chemical data needed as input for calculations that model atmospheric chemistry. A table summarizing the preferred rate data is provided, together with an appendix listing the available values of enthalpies of formation of the reactant and product species. © 2000 American Institute of Physics and American Chemical Society. |
|||
|
Show PACS
|
|||
This Publication
Scitation
Google Scholar
PubMed