The sepn. was demonstrated by studying the IR multiphoton dissocn. of CF2DCl [1495-14-3] and CF2HCl/CF2DCl mixts. It is shown how the parameters which control the IR photochem. of CF2DCl such as the temp. and the pressure, as well as the wavelength, the energy fluence and the intensity of the laser pulse, can be optimized for D sepn. IR anal. of the disappearing CF2DCl and CF2HCl peaks indicates isotopic selectivities in excess of 104. Dissocn. yields of up to 5% are obsd. at fluences around 6 J cm-2 with 30 ns pulses at pressures in the range 0.3 to 150 torr. A new route is presented for redeuteration of the D-depleted CF2HCl to natural abundance by way of high-temp. exchange in the gas phase.