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Atomic and Molecular Physics

The NIST Atomic Physics Program produces the most comprehensive set of reliable atomic data available anywhere.

The NIST collection of atomic energy levels, transition probabilities, and collision data is widely used by groups for characterizing and modeling all types of gaseous systems, including plasmas, planetary atmospheres, and astrophysical media, and for health physics applications. Databases and publications make these data easy to find and easy to use. The physics online databases have grown into an extensive listing. The NIST Chemistry WebBook now contains electronic and vibrational spectra for over 5000 compounds. The WebBook also contains constants of diatomic molecules.

The SRD Program has also produced several important compilations of molecular data.

The codes in the list below have the following meanings:

PC PC product, most available for purchase, some are free
Online Free online system
DG Inclusion in the NIST Data Gateway - a portal providing access to many NIST scientific and technical databases. It is searchable by keyword, property, or substance name.
* Product contains data that have undergone rigorous critical evaluation by experienced researchers who recommend best values.
Online Subscription Product is a yearly subscription web product.


SRD 64 NIST Elastic-Electron-Scattering Cross-Section Database, PC, DG, *
SRD 69 NIST Chemistry WebBook, Online, DG, *
SRD 7 NIST Electron and Positron Stopping Powers of Materials, PC, DG, *
SRD 82 NIST Electron Effective-Attenuation-Length Database, PC, DG, *
SRD 71 NIST Electron Inelastic-Mean-Free-Path Database, PC, DG, *
SRD 105 Elemental Data Index, online, DG, *
SRD 107 Electron-Impact Ionization Cross Section Database, Online, DG, *
SRD 108 Handbook of Basic Atomic Spectroscopic Data Online, DG, *
SRD 160 FLYCHK Collisional-Radiative Code, Online, DG, *
SRD 158 SAHA Plasma Population Kinetics Database, Online, DG, *
SRD 159 NLTE4 Plasma Population Kinetics Database, Online, DG, *
SRD 154 NIST Backscattering-Correction-Factor Database for Auger Electron Spectroscopy, PC, DG,*
SRD 164 NIST Database of Cross Sections for Inner-Shell Ionization by Electron or Positron Impact, PC, DG, *

Atomic Spectroscopic Data
SRD 141 Atomic Reference Data for Electronic Structure Calculation, Online, DG, *
SRD 78 Atomic Spectra Database , Online, DG, *
SRD 109 Atomic Spectral Line Broadening Bibliographic Database, Online, DG, *
SRD 110 Atomic Transition Probabilitiy Bibliographic Database, Online, DG, *
SRD 111 Ground Levels and Ionization Energies for the Neutral Atoms, Online, DG, *
SRD 112 Atlas of the Spectrum of Platinum/Neon Hollow-Cathode Lamp, Online, DG, *
SRD 113 Spectral Data for the Chandra X-ray Observatory, Online, DG, *
SRD 169 Bibliographic Database on Atomic Energy Levels and Spectra, Online, DG, *
SRD 105 Physic Laboratory's Elemental Data Index, Online

Molecular Spectroscopic Data
SRD 114 Diatomic Spectral Database, Online, *
SRD 115 Hydrocarbon Spectral Database, Online, *
NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions, Online, DG, *
SRD 117 Triatomic Spectral Database, Online, *
SRD 118 Wavenumber Tables for Calibration of Infrared Spectrometers, Online, DG, *
SRD 119 Vibrational branching ratios and asymmetry parameters in the photoionization of CO2 in the region between 650 Å and 840 Å, Online, DG, *

Nuclear Physics
SRD 144 Atomic Weights & Isotopic Composition, Online, DG, *
SRD 120 Radionuclide Half-Life Measurements, Online, DG, *

Physical Constants
SRD 121 Fundamental Physical Constants, Online, DG, *
Guidelines for Evaluating and Expressing Measurement Uncertainty, Online, DG, *
International System of Units (SI), Online, DG, *
Searchable Bibliography on the Constants, Online, DG, *

Radiation Dosimetry
SRD 124 Stopping-Power and Range Tables for Electrons, Protons, and Helium Ions, Online, DG, *

X-Ray and Gamma-Ray Data
SRD 125 Bibliography of Photon Total Cross Section, Online, DG, *
Note on x-ray attenuation databases, DG, *
SRD 8 XCOM: Photon Cross Sections Database, Online, DG, *
SRD 126 Tables of X-Ray Mass Attenuation Coefficients and Mass Energy - Absorption Coefficients, Online, DG, *
SRD 66 X-Ray Form Factor, Attenuation and Scattering Tabulation, Online, DG, *
SRD 20 NIST X-ray Photoelectron Spectroscopy Database 4.1, Online, DG, *
SRD 128 X-Ray Transition Energies Database, Online, DG, *