Chemistry Seminar with Professor Chris Greene Purdue University at 4:00pm

“Theory of Recombination Reactions” (Hosts: Professor Loomis and Professor Sobotka)

Recombination reactions are among the most challenging reactions involving small molecules for theoretical methods to describe. In this seminar I will describe the methods we have developed to treat two different types of recombination reactions. The first is the dissociative recombination reaction where a low energy electron collides with a small molecular ion, which then grabs the electron and dissociates into (usually) neutral fragments. Some of the systems where this process has been studied in experiments and theory include astrophysically important ions such as HeH+, H3+, CH+, and CH3+. In the case of the symmetric polyatomic ions, dynamic Jahn-Teller coupling is found to play a crucial role.

The second type of reaction discussed during this seminar will be 3-body and 4-body recombination reactions where 3 or 4 ultracold gas atoms or ions react in the continuum to form bound subsystems. This reaction is of particular interest in studies of quantum degenerate gases, especially in the range of very large scattering lengths where close connections with the physics of the Efimov effect are evident in both experiments and theory.
[1] “Dissociative Recombination of Cold HeH+ Ions”, R. Curik, D. Hvizdos, C. H. Greene, Physical Review Letters 124, 043401-1 to -5 (2020).
[2] "Dissociative recombination of highly symmetric polyatomic ions", N. Douguet, A. E. Orel, C. H. Greene, and V. Kokoouline, Phys. Rev. Lett. 108, 023202-1 to -5 (2012).
[3] “Universal few-body physics and cluster formation”, C. H. Greene, P. Giannakeas, and J. Perez-Rios, Rev. Mod. Phys. 89, 035006-1 to -66 (2017).