CO2 laser-induced photolysis of spirohexane: time resolved observation of vibrationally excited 1,3-butadiene

Article abstract of DOI:10.1016/0584-8539(92)80242-O

Vibrationally excited spirohexane (SHX) generated in CO2 laser irradiation undergoes photolysis producing ethylene, 1,3-butadiene and a C4 compound as major products.Collisional energy pooling plays a major role in the multiphoton excitation process.Time resolved formation of 1,3-butadiene is monitored by UV-absorption from which the unimolecular rate constant for SHX dissociation is found to be 5.6 x 10⁵s^-1.A red shift of 40 nm observed in the transient UV absorption spectrum has been assigned to nascent 1,3-butadiene, which suggests that vibrationally hot 1,3-butadiene molecules are formed.The effects of laser energy fluence an d pressure of SF6 as a sensitizer on dissociation yield are also investigated.