Photofragment translational

Ashfold M N R, Mordaunt D H and WIson S H S 1996 Photodissociation dynamics of hydride molecules H atom photofragment translational spectroscopy Adv. Photochem. 21 217-95... 

Fig. 11. Photofragment translational energy distribution (upper panel) and anisotropy distribution (lower panel) for the photolysis of H2S. The arrow in the upper panel marks the energetic onset for the generation of SH(A2S+, 1/) + H.

J. Helpburn, Photofragment translational spectroscopy, Atomic and Molecular Beam Methods, ed. G. Scoles (Cambridge Press). 

Fig. 19. Photofragment translational energy distribution from reactions (29b) and (34b). The translational energy distributions are the same for reactions (29b) and (34b) within the experimental uncertainty. The solid line represents the experimental measurement, and the dashed lines represent the upper and lower limits due to experimental uncertainty.

Fig. 4. Fast radical beam photofragment translational spectrometer. A fast free radical beam is produced from photodetachment of anions in a mass selected beam. The free radicals are then photodissociated in the downstream. (From Cyr et al.59)...

The photodissociation dynamics of jet-cooled methyl radical produced in a pyrolysis radical beam have been investigated at 193.3 nm using photofragment translational spectroscopy by North and co-workers.112 Only... 

Fig. 29. Photofragment translational energy distributions P(Et) and angular distributions 0(Et) for the CH3 + CO product channel of CH2CIIO(/ 2 A"). Vibronic assignments are given in addition to the excess energy for each transition.

Fig. 31. Photofragment translational energy distribution P(Et) for the H + CH2CO product channel of the CH2CHO photodissociation at 308.2 nm. (From Xu et al.18B)...

Ethoxy radical (CH3CH2O ) has enjoyed considerable interest as well. Choi et al. explored its photodissociation dynamics via photofragment translational... 

Photodissociation Dynamics of Hydride Molecules H Atom Photofragment Translational Spectroscopy (Ashfold, Mordaunt, and Wilson) Photo-Fries Rearrangement and Related Photochemical (l.j) Shifts of... 

While one might expect that the techniques developed for photodissociation studies of closed-shell molecules would be readily adaptable to free radicals, this is not the case. A successful photodissociation experiment often requires a very clean source for the radical of interest in order to minimize background problems associated with photodissociating other species in the experiment. Thus, molecular beam photofragment translation spectroscopy, which has been applied to innumerable closed-shell species, has been used successfully on only a handful of free radicals. With this problem in mind, we have developed a conceptually different experiment [4] in which a fast beam of radicals is generated by laser photodetachment of mass-selected negative ions. The radicals are photodissociated with a second laser, and the fragments are detected in coinci-... 

The photolysis of CH3NO2 by 193 nm laser light was studied by product emission spectroscopy and molecular beam photofragment translational energy spectroscopy by Butler et al. (119). Blais (120) also studied the photolysis by the TOF method. The primary process is... 

The qualitative picture suggested by these calculations has recently been confirmed by new experiments on the UV photochemistry of phenol. Lee and collaborators have shown that loss of H atoms is the major process in phenol at 248 nm excitation [36], Ashfold and co-workers have applied high-resolution photofragment translational spectroscopy to obtain uniquely detailed insight into the photodissociation dynamics of phenol [37], The phenoxy radical is produced in a surprisingly limited subset of its available vibrational states [37], Such vibrational mode-specific dynamics is a signature of ultrafast radiationless decay through directly accessible conical intersections. Similar results have been obtained for pyrrole, imidazole and indole [38 10],... 

The UV photochemistry of phenol and related systems (such as indole, pyrrole, imidazole) is dominated by a hydrogen detachment reaction which is driven by repulsive 1ira states [33,35 10], For the isolated chromophores, the 1 mr -driven photodissociation has been explored in unprecedented detail by high-resolution photofragment translational spectroscopy [40], The OH (or NH) bond is broken homolytically, resulting in the formation of two radical species, the hydrogen atom and the phenoxy (or indolyl, etc.) radical. Ion pair formation (abstraction of protons) is energetically not feasible for isolated photoacids. 

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