Photodissociation of 2-Bromobutane at ～265 nm by Ion-velocity Map Imaging Technique
- Received Date: 2012-05-07
Abstract: The photodissociation dynamics of 2-bromobutane has been investigated at 264.77 and 264.86 nm by ion-velocity map imaging technique coupled with resonance-enhanced multi-photon ionization. The speed and angular distributions have been derived from the velocity map images of Br and Br*. The speed distributions of Br and Br* atoms in the photodis-sociation of 2-bromobutane at ～265 nm can be fitted using only one Gaussian function indicating that bromine fragments were produced via direct dissociation of C-Br bond. Thecontributions of the excited 3Q0, 3Q1, and 1Q1 states to the products (Br and Br*) were discussed. It is found that the nonadiabatic 1Q1←3Q0 transition plays an important role for Br photofragment in the dissociation of 2-C4H9Br at ～265 nm. Relative quantum yield of 0.621 for Br(2P3/2) at ～265 nm in the photodissociation of 2-bromobutane is derived. By comparing the photodissociation of 2-C4H9Br at ～265 nm and that that at ～234 nm, the anisotropy parameter β(Br) and β(Br*), and relative quantum yield ?(Br) decrease with increasing wavelength, the probability of curve crossing between 3Q0 and 1Q1 decreases with increasing laser wavelength.
|Citation:||Dan-na Zhou, Rui Mao, Li-min Zhang, Qun Zhang, Yang Chen. Photodissociation of 2-Bromobutane at ～265 nm by Ion-velocity Map Imaging Technique[J]. Chinese Journal of Chemical Physics , 2012, 25(4): 373-378. doi: 10.1088/1674-0068/25/04/373-378|