Hi all, I encountered a problem similar to the one Carlo describes in his mail. I believe there is a bug in how TkAtoms reads 90 deg. angles from input files and (maybe) treats trigonal systems in hexagonal notation. Carlo: After reading in the input file, complete the lattice parametes by hand, i.e. enter the angles (90 deg) into the blank fields for alpha and beta. Then the calculation should work. If you don't enter the angles manually TkAtoms will obscure your structure. Watch the lattice parameters *after* running atoms! The value for the c axis will have changed so that a=b=c and you will get alpha=beta=gamma=120 deg. The other day I complained to Bruce about the calculation of the unit edge length (in the absorption card), printing out way to large sample thicknesses for an edge step of 1. In the meantime I noticed that the values for absorption length and unit edge length depend on whether I use the trigonal or the rhomohedral representation for my unit cell. Bruce: The values for the trigonal unit cell seem okay, maybe the problem is the treatment of the rhombohedral structure (not the specific wheight as I originally speculated). I have attached the two input files. Hope I could help! Best, Peter -- -------------------------------------------------------------- Peter Pfalzer Universitaet Augsburg Tel: +49-821-598-3215 Lehrstuhl fuer Experimentalphysik II Fax: +49-821-598-3411 Universitaetsstr. 1 D-86135 Augsburg Germany Peter.Pfalzer@physik.uni-augsburg.de -------------------------------------------------------------- ! This atoms input file was generated by TkAtoms 3.0beta7 ! Atoms written by and copyright (c) Bruce Ravel, 1998-2001 title = name: vanadium sesquioxide title = formula: V2O3 title = sites: V1,O1 title = refer1: Wyckoff vol 2, V, p 6-8 space = R -3 c a = 5.6470 b = 5.6470 c = 5.6470 alpha = 53.750 beta = 53.750 gamma = 53.750 core = V1 edge = K rmax = 6.0 shift 0.0000 0.0000 0.0000 atoms ! elem x y z tag occ. V 0.3463 0.3463 0.3463 V1 1.0000 O 0.5650 -0.0650 0.2500 O1 1.0000 ! This atoms input file was generated by TkAtoms 3.0beta7 ! Atoms written by and copyright (c) Bruce Ravel, 1998-2001 title = name: vanadium sesquioxide title = formula: V2O3 title = sites: V1,O1 title = refer1: Wyckoff vol 2, V, p 6-8 space = R -3 c a = 5.1050 b = 5.1050 c = 14.4490 alpha = 90.0 beta = 90.0 gamma = 120.0 core = V1 edge = K rmax = 6.0 shift 0.0000 0.0000 0.0000 atoms ! elem x y z tag occ. V 0.0000 0.0000 0.3463 V1 1.0000 O 0.3150 0.0000 0.2500 O1 1.0000