[MOS] February 24, 2015, Laurie Butler, University of Chicago

[Zina M Queen]

Seminar on

 

Modern Optics and Spectroscopy

Velocity Map Imaging:  Probing radical intermediates in chemical reactions

 

Laurie Butler,

University of Chicago 

Tuesday, February 24, 2015

12:00 – 1:00 p.m.



Radicals, molecules with an unpaired electron, are highly reactive intermediates in many important processes in the atmosphere, in biological oxidative stress, and in energy applications.  Bimolecular reactions may proceed through radical intermediates having more than 125 kJ/mol of internal energy, so these transient species may unimolecularly dissociate to form the products, be collisionally quenched, or react with side species in the bulk mixture.  To isolate the specific dissociation channels of these transient intermediates, we prepare each in a collision-free vacuum chamber by photodissociating an appropriate precursor.  I describe velocity map imaging experiments that allow us to fully characterize the velocity and the rotational and vibrational energy distributions of the radical intermediate, then to probe its dissociation channels as a function of internal energy and angular momentum.  We also characterize the photoionization detection of radical intermediates and products using both single frequency and tunable VUV laser sources. The experimental results allow us to test the predictions of statistical transition state theory and quasi-classical trajectory calculations.  They also allow us to benchmark new electronic structure methods to calculate the reactive energetics of open-shell systems.

  

Grier Room, MIT Bldg. 34-401

Refreshments served after the lecture
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