Calculation of tunnel splitting in a biaxial spin particle with an applied magnetic field Bin Zhou, Shun-Qing Shen and Jiu-Qing Liang Eur. Phys. J. B, 40 1 (2004) 87-92 Published online: 03 August 2004 DOI: 10.1140/epjb/e2004-00242-6