A 1Â fs spin-flip in a chemical reaction: Photodissociation of HF in solid Ar

(a) The HF bare molecule potentials without spin-orbit coupling interactions. The molecule contains 12 potentials: the ground state X1Σ+, the 3Π state, the excited to 1Π state and the 3Σ state (b) The HF molecule potentials in a slab of 255 Ar atoms along the 111 direction with spin-orbit interaction. The spin-orbit coupling interaction lifts some of the degeneracy and in addition, the once repulsive excited states of the bare molecule, become somewhat attractive.