FEL multiphoton dissociation and isotope separation of boron

The dependencies of dissociation yield and isotope selectivity on FEL frequency for boron trichloride were measured. The measurements have been performed by using metallic cell (38 cm3) filled with a mixture of BCl3 (2 Torr) and H2S (10 Torr). The maximum dissociation yield was obtained at a laser frequency shifted by 10 cm−1 toward the red side from the vibrational resonance of BCl3. The maximum selectivity was ∼1.5, which increased gradually with decreasing the laser frequency toward the red side from the resonance.