Spin-orbit coupling in the ground and low-lying excited states of HF+ and HF- X. G. Wu, M. J. Wan, C. Q. Song and T. Gao Eur. Phys. J. D, 60 2 (2010) 263-267 Published online: 27 July 2010 DOI: 10.1140/epjd/e2010-00203-8