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State Selectivity and Dynamics in Dissociative Electron Attachment to CF 3 I Revealed through Velocity Slice Imaging
Author(s) -
Ómarsson Frímann H.,
Mason Nigel J.,
Krishnakumar E.,
Ingólfsson Oddur
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201403859
Subject(s) - photodissociation , conical intersection , dissociation (chemistry) , chemistry , ground state , electron , excited state , atomic physics , chemical physics , photochemistry , physics , quantum mechanics
In light of its substantially more environmentally friendly nature, CF 3 I is currently being considered as a replacement for the highly potent global‐warming gas CF 4 , which is used extensively in plasma processing. In this context, we have studied the electron‐driven dissociation of CF 3 I to form CF 3 − and I, and we compare this process to the corresponding photolysis channel. By using the velocity slice imaging (VSI) technique we can visualize the complete dynamics of this process and show that electron‐driven dissociation proceeds from the same initial parent state as the corresponding photolysis process. However, in contrast to photolysis, which leads nearly exclusively to the 2 P 1/2 excited state of iodine, electron‐induced dissociation leads predominantly to the 2 P 3/2 ground state. We believe that the changed spin state of the negative ion allows an adiabatic dissociation through a conical intersection, whereas this path is efficiently repressed by a required spin flip in the photolysis process.