Skip to main content
Physics Division

Atomic Mass Data Resources

This page presents the basic resources made available by the Atomic Mass Data Center

Atomic Mass Evaluation - AME 2020

The AME 2020 atomic mass evaluation has been published in Chinese Phys. C 45, 030002 (2021) and Chinese Phys. C 45, 030003 (2021).

There are five main ASCII files associated with AME 2020:

  1. mass_1.mas20 - atomic masses [mass excess, binding energy/A, beta-decay energy, atomic mass]
  2. massround.mas20 - atomic masses rounded” version [mass excess, binding energy/A, beta-decay energy, atomic mass]
  3. rct1.mas20 - reaction energies, table 1 [S(2n), S(2p), Q(a), Q(2B-), Q(ep), Q(B-n)]
  4. rct2_1.mas20 - reaction energies, table 2 [S(1n), S(1p), Q(4B-), Q(d,a), Q(p,a), Q(n,a)]
  5. covariance.mas20 - variances and covariances of primary nuclides [note this file is a .zip file]

Any work that will use these files should make reference to the original papers listed above, and not to the electronic files.

NUBASE Evaluation - NUBASE2020

The NUBASE2020 evaluation has been published in Chinese Phys. C 45, 030001 (2021).

NUBASE contains experimentaly known nuclear properties, and some that have been estimated from extrapolation: mass, isomeric excitation energy, half-life, spin, parity, decay modes and intensities. An ASCII file of the NUBASE table, for use with computer programs, can be downloaded here:

Any work that will use this file should make reference to the original paper listed above, and not to the electronic file.

The Atomic Mass Evaluation and the NUBASE Evaluation is carried out every 4-5 years. The previous versions of the Evaluations are given below.

Atomic Mass Evaluation - AME 2016

The evaluation has been published in Chinese Physics C 41, 030002 (2017) and Chinese Physics C 41, 030003 (2017).

There are four main ASCII files associated with AME2016:

  1. mass16.txt - atomic masses [mass excess, binding energy/A, beta-decay energy, atomic]
  2. mass16round.txt - atomic masses rounded” version [mass excess, binding energy/A, beta-decay energy, atomic]
  3. rct1-16.txt - reaction energies, table 1 [S(2n), S(2p), Q(a), Q(2B-), Q(ep), Q(B-n)]
  4. rct2-16.txt - reaction energies, table 2 [S(1n), S(1p), Q(4B-), Q(d,a), Q(p,a), Q(n,a)]

Any work that will use these files should make reference to the original papers listed above, and not to the electronic files.

NUBASE Evaluation - NUBASE2016

The evaluation has been published in Chinese Physics C 41, 030001 (2017).

NUBASE contains experimentaly known nuclear properties, and some that have been estimated from extrapolation: mass, isomeric excitation energy, half-life, spin, parity, decay modes and intensities. An ASCII file of the NUBASE table, for use with computer programs, can be downloaded here:

Any work that will use this file should make reference to the original paper listed above, and not to the electronic file.

Atomic Mass Evaluation - AME 2012

The evaluation has been published in Chinese Physics C 36, 1287 (2012) and Chinese Physics C 36, 1603 (2012).

There are four main ASCII files associated with AME2012:

  1. mass.mas12 - atomic masses [mass excess, binding energy/A, beta-decay energy, atomic]
  2. rct1.mas12 - reaction energies, table 1 [S(2n), S(2p), Q(a), Q(2B-), Q(ep), Q(B-n)]
  3. rct2.mas12 - reaction energies, table 2 [S(1n), S(1p), Q(4B-), Q(d,a), Q(p,a), Q(n,a)]
  4. covariance.covar - variances and covariances of primary nuclides

Any work that will use these files should make reference to the original papers listed above, and not to the electronic files.

NUBASE Evaluation - NUBASE2012

The evaluation has been published in Chinese Physics C 36, 1157 (2012).

NUBASE contains experimentaly known nuclear properties, and some that have been estimated from extrapolation: mass, isomeric excitation energy, half-life, spin, parity, decay modes and intensities. An ASCII file of the NUBASE table, for use with computer programs, can be downloaded here:

Any work that will use this file should make reference to the original paper listed above, and not to the electronic file.