论文部分内容阅读
利用离子速度影像技术结合共振增强多光子电离(REMPI)技术,研究了邻溴甲苯在234和267 nm激光作用下的光解机理.平动能分布表明,基态Br(2P3/2)和自旋轨道激发态Br*(2P1/2)产生于两个解离通道:快通道和慢通道.快通道的各向异性参数在234 nm分别为1.15(Br)和0.55(Br*),在267 nm分别为0.90(Br)和0.60(Br*).慢通道的各向异性参数在234 nm分别为0.12(Br)和0.14(Br*),在267 nm分别为0.11(Br)和0.10(Br*).源自于慢通道的Br和Br*碎片的各向异性弱于快通道.Br(2P3/2)的相对量子产率Φ(Br)在234 nm为0.67,在267 nm为0.70.邻溴甲苯在234和267 nm光解主要产生基态产物Br(2P3/2).快通道产生于(π,π*)束缚单重态被激发,随后通过排斥性(n,σ*)态的预解离.慢通道各向异性参数接近零,由此证实慢通道来源于单重激发态内转换到高振动基态而引发的热解离.
The photolysis mechanism of o-bromotoluene at 234 and 267 nm was studied by means of ion-velocity imaging combined with resonance enhanced multiphoton ionization (REMPI) technique. The translational energy distribution shows that the Br (2P3 / 2) Excited state Br * (2P1 / 2) is generated in two dissociation channels: fast channel and slow channel.The anisotropy parameters of fast channel are 1.15 (Br) and 0.55 (Br *) at 234 nm, respectively Were 0.90 (Br) and 0.60 (Br *) respectively.The anisotropy parameters of slow channel were 0.12 (Br) and 0.14 (Br *) at 234 nm and 0.11 (Br) and 0.10 . The anisotropy of Br and Br * fragments originating from the slow channel is weaker than that of the fast channel.The relative quantum yield Φ (Br) of Br (2P3 / 2) is 0.67 at 234 nm and 0.70 at 267 nm. The photolysis of toluene at 234 and 267 nm mainly produces Br (2P3 / 2) as the ground state product, and the fast channel is generated by the (π, π *) bound singlet excited and then resolved by the repulsive (n, σ * The slow channel anisotropy parameter is near zero, confirming that the slow channel is derived from the thermal dissociation caused by the transition from the singlet excited state to the high vibrational ground state.