On Jul 1, 2014, at 10:43 AM, ZHAN Fei <zhanfei@ihep.ac.cn> wrote:

2 I have confusion of the relationship pf N between single path and multiple path,for example I think U-Oe-C U-Oe-Pshould be 1 2 respectively,instead 2 4 in paper.

I didn't look at the paper, but multiple scattering paths usually have even degeneracies because it counts separately when you go around the path in the opposite direction. Thus, if U is the absorber, U-Oe-C and U-C-Oe are separate but degenerate possibilities. So even if there is only one of each atom, the degeneracy would be 2.