Spectroscopic and thermal data were reviewed. The selected values for the principal moments of inertia, the vibrational fundamentals, and the standard enthalpy of formation at 298.15 K for each of the six chlorofluoromethanes were used to derive the chemical thermodynamic properties of molecules from 0 to 1500 K, based on the rigid-rotor harmonic-oscillator approximation. The calculated values are in accord with experimental heat capacities and entropies.

Survey of superconductive materials and critical evaluation of selected properties, B. W. Roberts, J. Phys. Chem. Ref. Data 5, No. 3, 581-822 (1976).

Key words: bibliography; composition; critical fields; critical temperature; crystallographic data; low temperature; superconductive materials; superconductivity.

This publication includes all data on superconductive materials intercepted through March 1975. Data on the bulk elements have been critically evaluated, and values on alloys, compounds, and other forms have been selected and condensed to indicate the probable value and spread of values observed. Proven nonsuperconductors have been noted. Conflict in data values has been noted. All data have been keyed to the literature in one or more of the tables. Special subdivisions are presented for superconductive materials with organic constituents and for those based on semiconductive materials. The properties presented are superconductive critical temperature, critical magnetic fields, material state and composition including crystal-structure type where noted, a key to thin-film forms, and the presence of thermodynamic data (generally the electronic specific heat, y, and Debye 0). High-magnetic-field superconductors are noted with listing of He, He, He, and He3 plus the temperature of observation Tobs.

Volume 5, No. 4

Nuclear spins and moments, G. H. Fuller, J. Phys. Chem. Ref. Data 5, No. 4, 835-1092 (1976).

Key words: evaluated data; nuclear electric hexadecapole moments; nuclear electric quadrupole moments; nuclear magnetic dipole moments; nuclear magnetic octupole moments; nuclear spins.

A summary of nuclear-moment values and an index, arranged by Z and A, is presented. The summary value is based on the experimentally determined values of the nuclear moments which have been listed in tables according to the techniques used. Each table is preceded by a short introduction describing the experimental technique involved and the method of calculating the moment from the measured quantities. References are given for all data quoted. The date for the last systematic literature search is included with each table. This tabulation supplements and revises the earlier tables which appeared in Nuclear Data Tables, Volume A5, 433-612 (1969).

Nuclear moments and moment ratios as determined by Mössbauer spectroscopy, J. G. Stevens and B. D. Dunlap, J. Phys. Chem. Ref. Data 5, No. 4, 1093-1122 (1976).

Key words: Mössbauer; nuclear electric quadrupole moments; nuclear magnetic dipole moments.

Values are given for Mössbauer effect measurements of nuclear magnetic moments, spectroscopic quadrupole moments, ratios of moments between low lying excited states and the ground state of the same isotope, and ratios of moments between states of different isotopes. Adopted values for moments, obtained by direct selection of specific results or by an averaging process, are presented. The literature has been covered through December 1974.

Rate coefficients for ion-molecule reactions I. Ions containing C and H, L. W. Sieck and S. G. Lias, J. Phys. Chem. Ref. Data 5, No. 4, 1123-1146 (1976).

Key words: chemical kinetics; data evaluation; gas phase; hydrocarbons; ion-molecule reactions; mass spectrometry; rate coefficients.

A compilation is presented of experimentally determined bimolecular and third order rate coefficients for the reactions of hydrocarbon ions with neutral molecules in the vapor phase. The literature covered is from 1960 to the present, and both positive and negative ions are considered. Four hundred and fifty-eight separate reaction-pairs are tabulated, and the ionic reaction products and experimental conditions are specified wherever possible. Preferred values are suggested for a number of these processes.

Microwave spectra of molecules of astrophysical interest. XI. Silicon Sulfide, E. Tiemann, J. Phys. Chem. Ref. Data 5, No. 4, 1147-1156 (1976).

Key words: interstellar molecules; microwave spectra; radio astronomy; rotational transitions; silicon sulfide; spec

tra.

The available data on the microwave spectrum of silicon sulfide are critically reviewed for information applicable to radio astronomy. Molecular data such as rotational constants, electric dipole moment and hyperfine coupling constant are tabulated. Observed rotational transitions are presented for all measured isotopic forms of SiS. These data have been analyzed in order to predict rotational transition of the ground vibrational state up to 300 GHz. From the given rotational constants transition frequencies in excited vibrational states can be calculated with little loss in accuracy.

Error limits have been taken from the original literature for each measured frequency. The predicted transition frequencies are given with uncertainties which represent the 90 percent confidence limit.

This monthly magazine is published to inform scientists, engineers, businessmen, industry, teachers, students, and consumers of the latest advances in science and technology, with primary emphasis on the work at NBS.

DIMENSIONS/NBS highlights and reviews such issues as energy research, fire protection, building technology, metric conversion, pollution abatement, health and safety, and consumer product performance. In addition, DIMENSIONS/NBS reports the results of Bureau programs in measurement standards and techniques, properties of matter and materials, engineering standards and services, instrumentation, and automatic data processing. Issued monthly.

January 1973

TNB 57, No. 1, 1-24 (1973).

Key words: Measures for air quality; metric chart; rf measurements; runway capacities; semiconductor materials test; speed of light.

Superconducting Sensor Advances RF Metrology

Determining Runway Capacities and Delays

Nondestructive Test of Semiconductor Materials

The Environment and the Economy: Joint Progress or Parochial Negativism

Measures for Air Quality

Insert-NBS Measurement Seminars, 1973 Series Experimental Measurement of Optical Frequency New Value for Speed of Light

NSRDS News

Publications of the National Bureau of Standards Prices Revised on Standard Reference Materials

February 1973

TNB 57, No. 2, 25-52 (1973).

Key words: Cancer detection; city games; temperature scale; truck noise; waste incineration.

Cancer Detected in Living Animals Using Nuclear Magnetic Resonance

City Games People Play

NBS Measurements Show Significant Temperature Scale Differences

Optical Radiation News

The Metric System - A Changeover is Under Way

Brief History of Measurement Systems with a Chart of the Modernized Metric System

NBS Helps with Problems of Waste Incineration NSRDS News

OIML Meeting

Publications of the National Bureau of Standards

March 1973

TNB 57, No. 3, 53-76 (1973).

Key words: Electrical engineering units; electron recombination reactions; heat pipe oven; lead-based paints; popular metric chart; tribo-ellipsometry.

Electron Recombination Reactions

New NBS Director - Dr. Richard W. Roberts

New Oven Constrains Corrosive Vapors

Lower Temperatures Recommended for Ranges

Electrical Engineering Units and Constants Cards Performance Standards for X-Ray Systems

NBS Aids U.S. Railroad System

NSRDS News

All You Will Need to Know About Metric

New Reference Tables for Low-Temperature Thermocouples Available

Using Tribo-Ellipsometry to Study Stress Corrosion Cracking

Standard Reference Material for Analyzing Lead-Based Paints Available

TV Time Petitions Sent to FCC

Publications of the National Bureau of Standards

April 1973

TNB 57, No. 4, 77-100 (1973).

Key words: Electrical power; insulation of buildings; inventor; kitchen range standards; Shirley Highway bus project; superconductive fixed-point device.

NBS Evaluates Express Bus Project

Transition Temperatures Certified Using Superconductive Fixed- Point Device

Environmental Testing of Full Size Buildings

Optical Radiation News

New Kitchen Range Standards

Shunt Reactor Power Loss