Vb. Laptev et al., SELECTIVE IR-LASER-INDUCED ISOMERIZATION AND DISSOCIATION OF BIS(TRIFLUOROMETHYL)KETENE MOLECULES, Laser chemistry, 16(4), 1996, pp. 255-264
Multiphoton IR laser induced isomerization and dissociation of(CF3)(2)
C=C=O (FMK) molecules have been studied. The antisymmetric stretch v(1
)=2192 cm(-1) of C=C=O-and antisymmetric v(16)=991 cm(-1) of C-C- bond
s were excited by the second- and first harmonics of a pulsed TEA CO2
laser. The cm dependence of isomerization conversion on laser radiatio
n frequency, fluence, and number of shots was measured. The isomerizat
ion channel was predominant compared with dissociation for the conditi
ons of IR multiphoton excitation under study. The isomerization of FMK
by the second-harmonic radiation of a CO2 laser was proved to be sele
ctive with respect to oxygen isotopes. The isomerization product (FMA
molecules) was enriched with O-18 with maximum value of selectivity al
pha(18/16)=3.9 when FMK molecules were excited at 2 omega(las)=2143.8c
m(-1).