Molecular contributions to the thermal neutron cross sections of O2, N2, and air
We provide an updated scattering library for the simulation of thermal neutron transport in air, including the effects of rotational and vibrational modes in N2 and O2 and neutron magnetic scattering in O2, showing their significance compared to smaller effects related to water humidity. The modeling is based on the Young-Koppel treatment of thermal neutron scattering from diatomic molecules, as well as ab initio simulations of the electronic density of O2. The theoretical predictions are benchmarked against experimental measurements of the total scattering cross section of air under monitored thermophysical conditions, in the neutron energy range between 0.6 meV and 10 keV. The updated scattering library is used to calculate excess neutron scattering in air, compared to traditional approaches, where only nuclear scattering from gases of free nuclei is implemented in Monte Carlo transport codes.
Authors
- Marco Martellucci
- R. Senesi (ORCID: https://orcid.org/0000-0002-5620-1165)
- Anna Marsicano (ORCID: https://orcid.org/0000-0002-5923-8641)
- T. Minniti (ORCID: https://orcid.org/0000-0002-9416-4510)
- M. Krzystyniak (ORCID: https://orcid.org/0000-0003-0307-6871)
- Giovanni Romanelli (ORCID: https://orcid.org/0000-0001-5963-4647)
- Tommaso Giovannini (ORCID: https://orcid.org/0000-0002-5637-2853)
- Margherita Simoni (ORCID: https://orcid.org/0009-0008-4297-5259)
- José Ignacio Márquez Damián (ORCID: https://orcid.org/0000-0002-9611-914X)
- Matteo Sorbara
- Felix Fernandez-Alonso
Institutions
- Ikerbasque (ES)
- University of Rome Tor Vergata (IT)
- Rutherford Appleton Laboratory (GB)
- European Spallation Source (SE)
- Institute of Structure of Matter (IT)
- Donostia International Physics Center (ES)
Publication Details
- Journal
- The Journal of Chemical Physics
- Published
- 2026-04-03
- DOI
- https://doi.org/10.1063/5.0324136
- Primary Topic
- Nuclear Physics and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Eusko Jaurlaritza
- Consiglio Nazionale delle Ricerche
- Science and Technology Facilities Council