Experimental And Theoretical Study On The Reaction Kinetics Of Halocarbene Radicals

This dissertation presents the experimental and theoretical studies on the reaction kinetics of halocarbenes. The first part is mainly about the experimental studies on the kinetics of HCFradical: (I) the quenching kinetics of HCF((A|⁾¹A") by alcohol and alkane molecules using LP/LIF technique. (2) the reaction kinetics of HCF((X|⁾¹A') with some small molecules using LP/LIF technique. The second part is about the theoretical studies on the kinetics of six halocarbenes reaction with NO and HCF reaction with C₂H₂ and C₂H₄ using quantum chemistry methods and TST-RRKM theory.Time-resolved kinetic study on quenching of HCF((A|⁾¹A") using LP/LIF technique:The HCF radicals were produced by laser photolysis of CHFBr₂ molecules at 213 nm and were then excited from the ground electronic state to (A|⁾¹A" state with Nd: YAG laser pumped dye laser at 492.58 nm which is corresponding to the transition of (A|⁾¹A"(030)←(X|⁾¹A'(000). The quenching rate constants k_q and thermally averaged cross section σ_q for collision quenching ofHCF((A|⁾¹A") state by normal alkane and alcohol molecules were measured at room temperature(298K) by observed the time-resolved fluorescence signals of the excited HCF in a cell at total pressure of about 14.0 Torr. Some regularity of the quenching rate constants with properties ofquenchers was obtained. It was shown that the quenching rate constants of HCF((A|⁾¹A") by the quenchers increase almost linearly with the number of C-H bonds contained in the homologous molecules. The formation cross sections σ_cf of the complex between HCF((A|⁾¹A") andquenchers were calculated by using collision complex model. The qualitative trendency of σ_cf is agreement with that of measured data. The results mean that the collisional quenching rates of HCF((A|⁾¹A") is probably controlled by the entranced channel, in which attractive forces via collision complex formation play an important role.