serdecznie zapraszamy na Seminarium Katedry Fizyki Teoretycznej i Informatyki Kwantowej, na którym
mgr Maciej Kosicki
Instytut Fizyki, Uniwersytet Mikołaja Kopernika w Toruniu
wygłosi wykład pt. "Towards sympathetic cooling of the SrF molecule and controlled chemistry at ultracold temperature"
Seminarium odbędzie się w najbliższy wtorek, 17 grudnia 2019 o godz. 11.30 w sali 418 GB.
Sympathetic cooling is a method that can allow transferring molecules into a single partial-wave regime. This process is based on cooling atomic and molecular species by immersion in a gas of coolant atoms. The method relies on elastic collisions to transfer momentum between the hot molecules and the coolant atoms. Inelastic collisions are detrimental to the cooling process as they release the internal energy of trapped molecules, leading to undesirable heating and trap loss. In addition, the inelastic collisions might also lead to final states that are no longer trappable. By providing numerical results, we show that the ultracold SrF molecule is a promising candidate to be sympathetically cooled by collisions with Rb atom in the presence of a magnetic field. A key step into this direction has been an evaluation of the ratio between elastic and inelastic collisions for the spin-polarized SrF and Rb complex. In particular, the state-of-the-art ab initio calculations have been employed to obtain molecular properties and the potential energy surface in the lowest triplet state. Next, the scattering parameters have been obtained using the converged close-coupling calculations based on the total angular momentum representation in the body-fixed coordinate frame.
We also investigate the isotopic substitution reaction, 'A + AB −> A + 'AB, in alkali-metal dimers and SrF molecule. These chemical reactions are exothermic and characterized by very small energy release. The exothermicity of the order of mK allows for an accumulation of
products in the trap after the chemical reaction. This is a promising route to direct measurement of reaction products. We have applied the statistical approach adopted for ultracold collisions to study the product state distributions, and we propose an experiment in which
they can be controlled using the external electric field. The presented results open new avenues in investigating the branching ratios of chemical reactions in ultracold conditions and may be used to provide details about the underlying dynamics of chemical reactions.
mgr Sylwia Sarniak