The effect of static elec. and magnetic fields on the IR multiphoton dissocn. (IRMPD) yield of CF3D was investigated in the range 0-4.3 kV cm-1 and 0-17.3 kG. The applied static fields induced increases in the reaction yield of up to a factor of 5 at moderate energy fluences in the essentially collision free dissocn. For all cases considered, the field effects were independent of the orientation of the laser beam polarization relative to the direction of the applied elec. and magnetic fields. At higher pressures, where collisions enhanced the reaction yield, lower yields were obsd. in the 17.3 kG magnetic field than in the magnet's residual field of .apprx.100 G. The measurements on the magnetic field effect were completed with new results on the IRMPD of CF2HCl. Possible IR spectral changes induced by a 5 kV cm-1 field in CF3D, CF3H, and CF2HCl were investigated at a resoln. of 0.06 cm-1.