Symmetries and dissociation dynamics of F 1s core excited states of BF₃

Using the photoelectron-energy-selected photoion coincidence technique, we find that photoions of BF₃ with kinetic energy larger than 4 eV are predominantly F⁺ in the F 1s ionization region whereas B⁺ is more intense than F⁺ at the F 1s→2a₂″ excitation. Two partial cross sections σ_∥ and σ_⊥ for A₁′→E′ parallel and A₁′→A₂″ perpendicular transitions are obtained from the angular distribution measurement of energetic photoions and the symmetries of some F 1s core excited states are confirmed. The dissociation dynamics of the F 1s^-12a₂″ core excited state are discussed in detail.