Professor Edvardas Narevicius, Weizmann Institute. "Cold chemistry with cold molecules." Woodward CCB Departmental Colloquium.
Abstract: Low temperature chemistry at the limit of the de Broglie wavelength exceeding dimensions of atoms and molecules requires a change in a chemist’s intuition. Whereas transition state is usually sufficient to describe “warm” chemical interactions, in the cold regime long-range interactions become equally important. Moreover quantum phenomena such as tunneling and quantum resonances start dominating dynamics dramatically changing reaction rates. Reaction may proceed as fast at 1 Kelvin as at room temperature. We will discuss the latest developments in the merged beam method that allows us to investigate cold chemistry with cold molecular species such as H2. We used the sensitivity of quantum resonances to investigate the effect of internal molecular degrees of freedom on cold interactions. We show that control over the rotational state effectively switches the orientation dependent interaction on or off, leading to stark differences in reactivity of para- and ortho-hydrogen at low collision energies.