Hi, we are trying to create a feff.inp file for the octahedral core of the monoclinic beta-Ga2O3 structure. If we enter '12' as space group, there are some atoms missing. However, if we use the symbolic 'c 2/m', everything is fine. This occurs with TkAtoms, as well as with the Atoms implementation in Artemis 0.8.007. I haven't tried Webatoms yet, but I assume it'll be the same. The .cif-file for b-Ga2O3 is included. Any clues ? Cheers, dominik First octahedron with 'c 2/m' as space group index: [...] ATOMS * this list contains 16 atoms * x y z ipot tag distance 0.00000 0.00000 0.00000 0 Ga2 0.00000 0 -1.93032 0.00000 0.14228 2 O3 1.93556 1 0.06926 1.51855 -1.20114 2 O1 1.93740 2 0.06926 -1.51855 -1.20114 2 O1 1.93740 3 1.99294 0.00000 0.22127 2 O2 2.00519 4 0.17363 1.51855 1.40203 2 O2 2.07409 5 0.17363 -1.51855 1.40203 2 O2 2.07409 6 0.00000 3.03710 0.00000 1 Ga2 3.03710 7 [...] END The same, with '12' as space group index. Please note the missing O2 in the first octahedron. There are also some other missing atoms: [...] ATOMS * this list contains 12 atoms * x y z ipot tag distance 0.00000 0.00000 0.00000 0 Ga2 0.00000 0 -1.93032 0.00000 0.14228 2 O3 1.93556 1 0.06926 1.51855 -1.20114 2 O1 1.93740 2 0.06926 -1.51855 -1.20114 2 O1 1.93740 3 0.17363 1.51855 1.40203 2 O2 2.07409 4 0.17363 -1.51855 1.40203 2 O2 2.07409 5 0.00000 3.03710 0.00000 1 Ga2 3.03710 6 [...] END -- Dipl.-Ing. Dominik Samuelis samuelis@pc.rwth-aachen.de Physikalische Chemie I RWTH Aachen University Phone: +49-241-80-94840 Fax: +49-241-80-92128 Landoltweg 2 52056 Aachen Germany data_83645-ICSD _audit_creation_date 107-01-11 _audit_creation_method 'generated by RETRIEVE 2.0' _database_code_ICSD 83645 _chemical_name_systematic 'Gallium oxide - $-beta' _chemical_formula_structural 'Ga2 O3' _chemical_formula_sum 'Ga2 O3' _publ_section_title 'A reinvestigation of $-beta-gallium oxide' loop_ _publ_author_name 'Ahman, J' 'Svensson, G' 'Albertsson, J' _journal_name_full 'Acta Crystallographica C (39,1983-)' _journal_coden_ASTM ACSCEE _journal_volume 52 _journal_year 1996 _journal_page_first 1336 _journal_page_last 1338 _cell_length_a 12.214(3) _cell_length_b 3.0371(9) _cell_length_c 5.7981(9) _cell_angle_alpha 90 _cell_angle_beta 103.83(2) _cell_angle_gamma 90 _cell_volume 208.8 _cell_formula_units_Z 4 _symmetry_space_group_name_H-M 'C 1 2/m 1' _symmetry_Int_Tables_number 12 _symmetry_cell_setting monoclinic loop_ _symmetry_equiv_pos_as_xyz 'x,y,z' 'x,-y,z' '-x,-y,-z' '-x,y,-z' '1/2+x,1/2+y,z' '1/2+x,1/2-y,z' '1/2-x,1/2-y,-z' '1/2-x,1/2+y,-z' loop_ _atom_type_symbol _atom_type_oxidation_number Ga3+ 3.000 O2- -2.000 loop_ _atom_site_label _atom_site_type_symbol _atom_site_symmetry_multiplicity _atom_site_Wyckoff_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_occupancy _atom_site_attached_hydrogens _atom_site_calc_flag Ga1 Ga3+ 4 i 0.09050(2) 0. 0.79460(5) 1. 0 d Ga2 Ga3+ 4 i 0.15866(2) 0.5 0.31402(5) 1. 0 d O1 O2- 4 i 0.1645(2) 0. 0.1098(3) 1. 0 d O2 O2- 4 i 0.1733(2) 0. 0.5632(4) 1. 0 d O3 O2- 4 i -0.0041(2) 0.5 0.2566(3) 1. 0 d _refine_ls_R_factor_all 0.022
On Friday 09 March 2007 06:32, Dominik Samuelis wrote:
we are trying to create a feff.inp file for the octahedral core of the monoclinic beta-Ga2O3 structure. If we enter '12' as space group, there are some atoms missing. However, if we use the symbolic 'c 2/m', everything is fine. This occurs with TkAtoms, as well as with the Atoms implementation in Artemis 0.8.007. I haven't tried Webatoms yet, but I assume it'll be the same. The .cif-file for b-Ga2O3 is included. Any clues ?
Domink, That space group is one of the monoclinic groups that has several settings. Saying "12" doesn't tell the program which is the correct setting. Saying "C 2/m" does. That said, it should not have made a difference in this case because "C 2/m" is the fallback setting when the space group is given as "12". However, you are correct that something is wrong. It seems as though the Bravais translation is not being applied when "12" is given as the space group, but it is when "C 2/m" is given as the space group. That's a bug. Thanks for reporting it. My codes improve when I get good bug reports like this one. Using the symbol if you know it is a good idea, in any case. It conveys more information than the number. B -- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/
participants (2)
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Bruce Ravel
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Dominik Samuelis