Speaker: Tomas Baer (Chemistry Department, University of North Carolina, USA) Title: Photoelectron photoion coincidence studies with electron velocity focusing. The road to ± 0.1 kJ/mol thermochemistry Time: Today, May 4, 10.15 to 11.00 Place: Fysisk Auditorium Abstract: Threshold photoelectron photoion coincidence (TPEPICO) is used to energy select reactant ions in order to study the dissociation dynamics (rates, branching ratios to various products, product energy distributions) of polyatomic ions. Analysis of the ion time of flight distributions and breakdown diagrams using the statistical theory of unimolecular dissociation permits modeling multiple parallel and sequential dissociation steps, and thus permits extracting quantitative onset energies for higher energy dissociation channels. A recent implementation of this experiment at the Swiss Light Source (SLS) has improved the electron resolution to ± 1 meV, which will lead to 0.1 kJ/mol thermochemistry. Among the molecules investigated at the SLS are the sequential dissociation of MCl4+ to M+ + 4Cl, (M = Sn and Ge). The heat of formation of the neutral MCl4 can be determined by using the final products as an energy anchor. Peter Staanum and Nicolai Nygaard Coffee, tea and rundstykker will be served at 10.05. N.B. There is also an AMO seminar Thursday this week by Guido Pupillo.