Optical spectroscopy of the radioactive isotopologue of methane (14CH4) has interesting applications ranging from energy industry to atmospheric sciences. As an example, radioactive gaseous emissions of light water nuclear reactors and their decommissioning sites can be monitored by measuring the 14CH4 concentration. Since the 14CH4 concentration is depleted in fossil sources with a 14C half-life of 5700 years, measurements of the 14CH4/12CH4 ratio also make it possible to determine the biofractions of biogas and natural gas mixtures, as well as to apportion methane emission sources.
We have carried out the first accurate measurements and spectroscopic analysis of the absorption spectrum of the ν3(F2) band of 14CH4. The obtained accurate line position information is needed for the development of online in-situ radiocarbon methane detectors based on highly sensitive laser spectroscopy.
Article preprint: arXiv:2004.07518 (Accepted for publication in Chem. Phys. Lett: https://www.sciencedirect.com/science/article/pii/S0009261420304036 )