Jeong, Your questions are of the sort that I always wish the folks working on Feff8 would volunteer an answer for, but I will do what I can.
I have another questions. I got the charge transfer of TiO2 from FEFF8 as following; Ti: (not absorber) Charge transfer : 0.556 Electron counts for each orbital momentum: 0 0.408 1 6.678 2 2.350 3 0.000 O: Charge transfer : -0.280 Electron counts for each orbital momentum: 0 1.843 1 4.354 2 0.087 3 0.000
It is known that the electron number of Ti atom ( the atomic number 22)&nbs! p;is 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^2.
Yes, but Feff8 is just considering the valence electrons. The core electrons are not included in those counts.
In the results of FEFF, 0 is s orbital, 1 is p orbital so on.. right?
That is correct. The number in the left column is the angular momentum quantum number.
as you know, there is each s-orbital or p-orbital in principal quantum number. which orbital momentum of principle quantum number does 0, 1, 2 and 3 mean?
To the best of my knowledge, Feff8 does not make that clear. For most elements, it considers the valence electrons of a particular angular momentum to be the highest lying ones. See the subroutine corval contained in the file POT/corval.f in the Feff8 source tree for more details.
second I cant understand electron counts. I thought that Charge transfer was calculated by electron counts for each orbital momentum, comparing the electron counts of free atom. So I tried to calculate like this: In free oxygen atom case, 2^s has 2 electron, 2^p has 4 electron. The electron counts calculated by FEFF8 is 1.843 + 4.354 + 0.087 =6.284 So charge transfer is 6 - 6.284 = 0.284 The charge thransfer, 0.284, obtained from my calculation is different from the value of FEFF8. How can I get charge transfer form electron counts?
I think the problem is that you are not considering the stoichiometry (or the relative number of Ti and O atoms used in the calculation (see http://leonardo.phys.washington.edu/feff/wiki/index.php?title=POTENTIALS, otherwise it is determined from the contents of the cluster). HTH, B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 My homepage: http://xafs.org/BruceRavel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/