BaF radical: A promising candidate for laser cooling and magneto-optical trapping

Recently, there have been great interest and advancement in the field of laser cooling and magneto-optical trapping of molecules. The rich internal structure of molecules naturally lends themselves to extensive and exciting applications. In this paper, the radical ¹³⁸Ba¹⁹F, as a promising candidate for laser cooling and magneto-optical trapping, is discussed in detail. The highly diagonal Franck-Condon factors between the X²Σ_1/2⁺ and A²Π_1/2 states are first confirmed with three different methods. Afterwards, with the effective Hamiltonian approach and irreducible tensor theory, the hyperfine structure of the X²Σ_1/2⁺ state is calculated accurately. A scheme for laser cooling is given clearly. Besides, the Zeeman effects of the upper (A²Π_1/2) and lower (X²Σ_1/2⁺) levels are also studied, and their respective g factors are obtained under a weak magnetic field. Its large g factor of the upper state A²Π_1/2 is advantageous for magneto-optical trapping. Finally, by studying Stark effect of BaF in the X²Σ_1/2⁺, we investigate the dependence of the internal effective electric field on the applied electric field. It is suggested that such a laser-cooled BaF is also a promising candidate for precision measurement of electron electric dipole moment.