The Li + CaF → Ca + LiF chemical reaction under cold conditions

Area of Science:

• Quantum chemistry
• Chemical physics
• Ultracold molecular science

Background:

• Calcium monofluoride (CaF) is a promising molecule for precision measurements and quantum simulations.
• Collisions involving cold Li atoms and CaF molecules are of significant experimental interest.
• Understanding reactive collisions is crucial for applications in ultracold chemistry.

Purpose of the Study:

• To perform ab initio electronic structure calculations for the Li + CaF system.
• To conduct full-dimensional quantum dynamical calculations for the Li + CaF → LiF + Ca reaction.
• To investigate the reaction dynamics under cold conditions (1-100 mK).

Main Methods:

• Electronic structure calculations using the internally contracted multi-reference configuration-interaction method with Davidson correction (MRCI + Q).
• Analytic fitting of interaction energies via a many-body expansion.
• Coupled-channel quantum reactive scattering calculations in hyperspherical coordinates.

Main Results:

• The Li + CaF reaction populates low-lying vibrational and many rotational levels of the LiF product.
• The reaction exhibits low efficiency in the 1-100 mK temperature range.
• This inefficiency suggests potential for sympathetic cooling of CaF by Li atoms.

Conclusions:

• The Li + CaF reaction dynamics have been accurately characterized using theoretical methods.
• The low reactivity at ultracold temperatures supports the use of Li atoms for sympathetic cooling of CaF.
• This work provides crucial insights for experiments in ultracold chemistry and precision measurements.