<!DOCTYPE html><html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /></head><body>Dear All,<div><br></div><div>I am working on a monoclinic material which has space group 15. It has C2/c point group.</div><div><br></div><div>When I run the pwscf, it gives me the C2/m point group that corresponds to the space group 12.</div><div><br></div><div><div> point group C_2h (2/m) </div><div> there are 4 classes</div><div> the character table:</div><div><br></div><div> E C2 i s_h </div><div>A_g 1.00 1.00 1.00 1.00</div><div>B_g 1.00 -1.00 1.00 -1.00</div><div>A_u 1.00 1.00 -1.00 -1.00</div><div>B_u 1.00 -1.00 -1.00 1.00</div></div><div><br></div><div><br></div><div>The symmetry operations of these two monoclinic space groups have 8 symmetry operations. <b>pwscf symmetry calculations found just 4...what about the other 4?</b> </div><div><br></div><div>I have checked the space groups from "http://www.cryst.ehu.es/cryst/get_gen.html":</div><div><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">General Positions of the Group 12 (</span><i style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">C</i><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">2</span><i style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">/m</i><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">) [unique axis b]</span><br></div><big style="font-family: 'Times New Roman';">1. x,y,z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">2. -x,y,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">3. -x,-y,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">4. x,-y,z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">5. x+1/2,y+1/2,z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">6. -x+1/2,y+1/2,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">7. -x+1/2,-y+1/2,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><div><span style="font-family: 'Times New Roman';">8. x+1/2,-y+1/2,z</span> </div><div><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;"><br></span></div><div><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">General Positions of the Group 15 (</span><i style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">C</i><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">2</span><i style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">/c</i><span style="font-size: medium; font-family: arial, verdana, helvetica, sans-serif;">) [unique axis b]</span></div><div><big style="font-family: 'Times New Roman';">1. x,y,z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">2. -x,y,-z+1/2</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">3. -x,-y,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">4. x,-y,z+1/2</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">5. x+1/2,y+1/2,z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">6. -x+1/2,y+1/2,-z+1/2</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">7. -x+1/2,-y+1/2,-z</big><br style="font-family: 'Times New Roman'; font-size: medium;"><big style="font-family: 'Times New Roman';">8. x+1/2,-y+1/2,z+1/2</big><br></div><div> <br></div><div><br></div><div>Here is the lite-input:</div><div><div>&control</div><div> calculation = 'scf',</div><div> restart_mode = 'from_scratch',</div><div> pseudo_dir = '/home//tlg2/pseudos',</div><div> outdir = './outdir',</div><div> prefix = 'TlGaSe2',</div><div> verbosity = 'high'<br></div><div>/<br></div><div>&system</div><div>ibrav = -13<br></div><div>celldm(1)=20.166973593</div><div>celldm(2)=0.999721681046</div><div>celldm(3)=1.453103256</div><div>celldm(5)=-0.173527859407</div><div> nat = 32</div><div> ntyp = 3</div><div> ecutwfc = 65</div><div> ecutrho = 650</div><div>/</div><div>&electrons</div><div> diagonalization = 'david'</div><div> diago_david_ndim = 8</div><div> mixing_mode = 'plain'</div><div> mixing_beta = 0.7</div><div> mixing_ndim = 8</div><div> conv_thr = 1.0d-8,</div><div>/</div></div><div><div>ATOMIC_SPECIES</div><div> Tl 204.3833 Tl.pbesol-dn-rrkjus_psl.1.0.0.UPF</div><div> Ga 69.7230 Ga.pbesol-dn-rrkjus_psl.1.0.0.UPF</div><div> Se 78.9600 Se.pbesol-dn-rrkjus_psl.1.0.0.UPF</div><div><br></div><div>ATOMIC_POSITIONS crystal</div><div>Tl 0.153800000000000 0.775600000000000 0.114000000000000</div><div>Tl 0.224400000000000 0.846200000000000 0.386000000000000</div><div>Tl 0.846200000000000 0.224400000000000 0.886000000000000</div><div>Tl 0.775600000000000 0.153800000000000 0.614000000000000</div><div>Tl 0.222100000000000 0.346700000000000 0.386400000000000</div><div>Tl 0.653300000000000 0.777900000000000 0.113600000000000</div><div>Tl 0.777900000000000 0.653300000000000 0.613600000000000</div><div>Tl 0.346700000000000 0.222100000000000 0.886400000000000</div><div>Se 0.946000000000000 0.054000000000000 0.250000000000000</div><div>Se 0.054000000000000 0.946000000000000 0.750000000000000</div><div>Se 0.426000000000000 0.574000000000000 0.250000000000000</div><div>Se 0.574000000000000 0.426000000000000 0.750000000000000</div><div>Se 0.145000000000000 0.269000000000000 0.071000000000000</div><div>Se 0.731000000000000 0.855000000000000 0.429000000000000</div><div>Se 0.855000000000000 0.731000000000000 0.929000000000000</div><div>Se 0.269000000000000 0.145000000000000 0.571000000000000</div><div>Se 0.952000000000000 0.572000000000000 0.252000000000000</div><div>Se 0.428000000000000 0.048000000000000 0.248000000000000</div><div>Se 0.048000000000000 0.428000000000000 0.748000000000000</div><div>Se 0.572000000000000 0.952000000000000 0.752000000000000</div><div>Se 0.736000000000000 0.360000000000000 0.438000000000000</div><div>Se 0.640000000000000 0.264000000000000 0.062000000000000</div><div>Se 0.264000000000000 0.640000000000000 0.562000000000000</div><div>Se 0.360000000000000 0.736000000000000 0.938000000000000</div><div>Ga 0.909000000000000 0.291000000000000 0.162000000000000</div><div>Ga 0.709000000000000 0.091000000000000 0.338000000000000</div><div>Ga 0.091000000000000 0.709000000000000 0.838000000000000</div><div>Ga 0.291000000000000 0.909000000000000 0.662000000000000</div><div>Ga 0.707000000000000 0.583000000000000 0.339000000000000</div><div>Ga 0.417000000000000 0.293000000000000 0.161000000000000</div><div>Ga 0.293000000000000 0.417000000000000 0.661000000000000</div><div>Ga 0.583000000000000 0.707000000000000 0.839000000000000</div><div>K_POINTS automatic</div><div>2 2 1 1 1 1</div></div><div><br></div><div>The primitive cell has been created by cif2cell code using the cif file as following:</div><div><br></div><div><div>_journal_issue 12</div><div>_journal_name_full 'Chemistry of Materials'</div></div><div><div>_journal_page_first 3120</div><div>_journal_volume 23</div><div>_journal_year 2011</div><div>_chemical_formula_structural 'Tl Ga Se2'</div><div>_chemical_formula_sum 'Ga Se2 Tl'</div><div>_chemical_name_systematic 'Thallium Gallium Selenide'</div><div>_space_group_IT_number 15</div><div>_symmetry_Int_Tables_number 15</div><div>_symmetry_space_group_name_Hall '-C 2yc'</div><div>_symmetry_space_group_name_H-M 'C 1 2/c 1'</div><div>_audit_creation_date 2008/02/01</div><div>_cell_angle_alpha 90.</div><div>_cell_angle_beta 99.993(6)</div><div>_cell_angle_gamma 90.</div><div>_cell_formula_units_Z 16</div><div>_cell_length_a 10.779(2)</div><div>_cell_length_b 10.776(1)</div><div>_cell_length_c 15.663(5)</div><div>_cell_volume 1791.7(7)</div><div>_refine_ls_R_factor_all 0.0652</div><div>_[local]_cod_data_source_file cm200946y_si_002.cif</div><div>_[local]_cod_data_source_block 157752-ICSD</div><div>_[local]_cod_chemical_formula_sum_orig 'Ga1 Se2 Tl1'</div><div>_cod_original_cell_volume 1791.73</div><div>_cod_database_code 4000782</div><div>loop_</div><div>_symmetry_equiv_pos_site_id</div><div>_symmetry_equiv_pos_as_xyz</div><div>1 'x, -y, z+1/2'</div><div>2 '-x, -y, -z'</div><div>3 '-x, y, -z+1/2'</div><div>4 'x, y, z'</div><div>5 'x+1/2, -y+1/2, z+1/2'</div><div>6 '-x+1/2, -y+1/2, -z'</div><div>7 '-x+1/2, y+1/2, -z+1/2'</div><div>8 'x+1/2, y+1/2, z'</div><div>loop_</div><div>_atom_site_aniso_label</div><div>_atom_site_aniso_type_symbol</div><div>_atom_site_aniso_U_11</div><div>_atom_site_aniso_U_22</div><div>_atom_site_aniso_U_33</div><div>_atom_site_aniso_U_12</div><div>_atom_site_aniso_U_13</div><div>_atom_site_aniso_U_23</div><div>Tl1 Tl1+ 0.052(6) 0.063(5) 0.06(2) -0.022(3) 0.005(8) 0.000(5)</div><div>Tl2 Tl1+ 0.044(6) 0.044(6) 0.07(2) -0.022(3) 0.005(8) 0.002(5)</div><div>Ga1 Ga3+ 0.015(9) 0.001(6) 0.05(3) 0.009(6) 0.01(2) -0.019(9)</div><div>Ga2 Ga3+ 0.019(7) 0.037(9) 0.00(3) -0.008(9) -0.01(1) -0.01(1)</div><div>Se1 Se2- 0.03(1) 0.02(1) 0.06(5) 0. 0.02(2) 0.</div><div>Se2 Se2- 0.006(9) 0.001(7) 0.06(4) 0. -0.01(2) 0.</div><div>Se3 Se2- 0.04(1) 0.05(1) 0.01(4) 0.01(1) -0.01(2) -0.02(1)</div><div>Se4 Se2- 0.012(6) 0.021(7) 0.06(4) 0.01(1) -0.018(9) -0.018(5)</div><div>Se5 Se2- 0.05(1) 0.06(1) 0.00(4) -0.053(9) -0.01(2) -0.02(1)</div><div>loop_</div><div>_atom_site_label</div><div>_atom_site_type_symbol</div><div>_atom_site_symmetry_multiplicity</div><div>_atom_site_Wyckoff_symbol</div><div>_atom_site_fract_x</div><div>_atom_site_fract_y</div><div>_atom_site_fract_z</div><div>_atom_site_occupancy</div><div>_atom_site_attached_hydrogens</div><div>Tl1 Tl1+ 8 f 0.4647(6) 0.3109(5) 0.1140(9) 1. 0</div><div>Tl2 Tl1+ 8 f 0.2844(4) 0.0623(5) 0.3864(8) 1. 0</div><div>Ga1 Ga3+ 8 f 0.100(1) 0.191(2) 0.162(2) 1. 0</div><div>Ga2 Ga3+ 8 f 0.145(1) 0.438(1) 0.339(2) 1. 0</div><div>Se1 Se2- 4 e 0. 0.054(2) 0.250 1. 0</div><div>Se2 Se2- 4 e 0. 0.574(1) 0.250 1. 0</div><div>Se3 Se2- 8 f 0.207(1) 0.062(1) 0.071(2) 1. 0</div><div>Se4 Se2- 8 f 0.262(1) 0.310(1) 0.252(2) 1. 0</div><div>Se5 Se2- 8 f 0.048(2) 0.312(1) 0.438(3) 1. 0</div><div>loop_</div><div>_atom_type_symbol</div><div>_atom_type_oxidation_number</div><div>Ga3+ 3</div><div>Se2- -2</div><div>Tl1+ 1</div><div>loop_</div><div>_citation_id</div><div>_citation_year</div><div>_citation_page_first</div><div>_citation_page_last</div><div>primary 2007 663 666</div></div><div><br></div><div><b>Are there something wrong in my input file or primitive cell?</b></div><div><br></div><div>With my best wishes,</div><div><br></div><div> Mutlu.<br><div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">------------------------------------------</div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">Dr. Mutlu COLAKOGULLARI</div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">Trakya Universitesi </div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">Fen Fakultesi</div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">Fizik Bolumu</div><div class="crea-font-wrapper" style="font-family: Tahoma; font-size: 16px;">22030 Merkez-EDİRNE</div></div></div></body></html>