Nuclear spin conversion in CH3F induced by an alternating electric field

The nuclear spin conversion in CH3F molecules subjected to an alternating e lectric field was investigated experimentally. The conversion rate was foun d to be almost unaffected by low electric fields (less than or equal to 200 V/m) but sharply increased tenfold when the electric field amplitude excee ds the values (similar or equal to 800 V/cm) sufficiently high to produce c rossings of the ortho and para states of the molecule. A theoretical model For the molecular conversion in alternating: electric field was developed. The results of the experiment were found to be in a good agreement with the theory.