This database contains critically evaluated transition frequencies for the molecular transitions detected in interstellar and circumstellar clouds reported in the literature through mid-2008. The tabulated transition frequencies are recommended for reference in future astronomical observations in the centimeter and millimeter wavelength regions. The transition frequencies have been selected through a critical examination and analysis of the laboratory spectral data obtained from the literature.

The databases ESTAR, PSTAR, and ASTAR calculate stopping-power and range tables for electrons, protons, or helium ions. Stopping-power and range tables can be calculated for electrons in any user-specified material and for protons and helium ions in 74 materials.

References contained in this database are from Bibliography on Atomic Energy Levels and Spectra, NBS Special Publication 363 and Supplements, as well as current references since the last published bibliography collected by the NIST Atomic Spectroscopy Data Center (http://www.nist.gov/physlab/div842/grp01/asdc_info.cfm).

The NIST Database of Cross Sections for Inner-Shell Ionization by Electron or Positron Impact provides cross sections for ionization of the K shell and of the L and M subshells of neutral atoms of the elements, from hydrogen to einsteinium, by electrons or positrons, for projectile energies from the ionization threshold to 1 GeV. These cross sections were calculated from a combination of the relativistic distorted-wave and the plane-wave Born approximations.

Standard Reference Material 131h Refined Cast Iron - This Standard Reference Material (SRM) is intended primarily for use in validation of chemical and instrumental methods of analysis. It can be used to validate value assignment of in-house reference materials and, if necessary, to calibrate carbon/sulfur analyzers. A unit of SRM 131h consists of a bottle containing 100 g of chips. This data is public in the Certificate of Analysis for this material.

SRM 1546a Meat Homogenate - This Standard Reference Material (SRM) is intended primarily for validation of methods for determining fatty acids, cholesterol, proximates, calories, elements, vitamins, and amino acids in canned meat products and similar materials. This SRM can also be used for quality assurance when assigning values to in-house reference materials. The meat homogenate is a mixture of pork and chicken products blended together in a commercial process. A unit of SRM 1546a consists of four cans, each containing approximately 85 g of material.

Standard Reference Material 1632d Trace Elements in Coal (Bituminous) - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of techniques used in the analysis of coals and materials of a similar matrix. A unit of SRM 1632d consists of 50 g of bituminous coal that was ground to pass a 250 µm (60 mesh) sieve, homogenized, bottled under an argon atmosphere, and sealed in an aluminized bag. This data is public in the Certificate of Analysis for this material.

SRM 1632e Trace Elements in Coal (Bituminous) - This Standard Reference Material (SRM) is intended primarily for use in the evaluation of techniques used in the analysis of coals and materials of a similar matrix.

SRM 1633c Trace Elements in Coal Fly Ash - This Standard Reference Material (SRM) is intended for use in the evaluation of analytical methods for the determination of constituent elements in coal fly ash or materials of a similar matrix. SRM 1633c is a bituminous coal fly ash that was sieved through a nominal sieve opening of 74 µm (200 mesh) and then blended to assure homogeneity. A unit of SRM 1633c consists of 75 g of powdered material. This data is public in the Certificate of Analysis for this material.

SRM 1635a Trace Elements in Coal (Subbituminous) - This Standard Reference Material (SRM) is intended primarily for the evaluation of techniques used in the analysis of coals and materials of a similar matrix. A unit of SRM 1635a consists of 50 g of subbituminous coal that was ground to pass a 250 µm (60 mesh) sieve, homogenized, bottled under an argon atmosphere, and sealed in an aluminized bag. This data is public in the Certificate of Analysis for this material.