Nuclear spin-rotation interaction in CF2 ((X)over-tilde(1)A(1)) observed by Fourier transform microwave spectroscopy

The rotational spectrum of difluoromethylene (CF2) in its (X) over tilde(1) A(1) ground electronic state has been observed using molecular beam-Fourier transform microwave spectroscopy. CF2 was produced in a free jet expansion in Ar as inert carrier gas by ArF excimer laser photolysis of CF2Cl2, CF2C HCl, or CF2CHBr or by flash pyrolysis of CF2Br2 in the high-pressure region directly behind a pulsed molecular beam valve. Rotational transitions were observed in the frequency range from 8 to 40 GHz in the CF2 (000) ground v ibrational state and in the (100), (010), and (001) excited vibrational sta tes. Several observed lines were split due to the hyperfine interaction bet ween the F-19 nuclear spin and the overall rotation of the molecule. The re sults were used to determine the nuclear spin-rotation interaction paramete rs for CF2. (C) 2000 Elsevier Science B.V. All rights reserved.