Hyperfine spectra of CH3F nuclear spin conversion

A theoretical model of hyperfine spectra of nuclear spin conversion of molecular isomers has been developed. The model takes into account the nuclear spin-spin and spin-rotation interactions, as well as the saturation of intramolecular mixing of molecular ortho and para states. The model has been applied to hyperfine spectra of nuclear spin conversion in 13 CH 3 F molecules subjected to an external electric field. Conditions under which the hyperfine structure in the spectra can be resolved have been determined.