From owner-nwchem-users@emsl.pnl.gov Tue Nov 22 01:22:20 2005 Received: from odyssey.emsl.pnl.gov (localhost [127.0.0.1]) by odyssey.emsl.pnl.gov (8.12.10/8.12.10) with ESMTP id jAM9MKWH007482 for ; Tue, 22 Nov 2005 01:22:20 -0800 (PST) Received: (from majordom@localhost) by odyssey.emsl.pnl.gov (8.12.10/8.12.10/Submit) id jAM9MKRH007481 for nwchem-users-outgoing-0915; Tue, 22 Nov 2005 01:22:20 -0800 (PST) Date: Tue, 22 Nov 2005 10:22:13 +0100 (CET) From: Kuba Kaminski Subject: [NWCHEM] problem with surface keyword X-X-Sender: qba@mml Cc: nwchem-users@emsl.pnl.gov Message-id: MIME-version: 1.0 Content-type: TEXT/PLAIN; charset=US-ASCII Sender: owner-nwchem-users@emsl.pnl.gov Precedence: bulk Dear nwchem users, I am trying to calculate silicon surface by running pspw - band tandem with NWChem 4.6. The geometry of Si unit cell and lattice parameters are specified in my input like this: geometry units au center noautosym noautoz print system surface lat_a 10.3651631 lat_b 10.3651631 lat_c 10.3651631 alpha 90.0 beta 90.0 gamma 90.0 end Si 0.0 0.0 0.0 Si 0.5 0.5 0.0 Si 0.0 0.5 5.18258155 Si 0.5 0.0 5.18258155 Si 0.75 0.75 2.591290775 Si 0.75 0.25 7.773872325 Si 0.25 0.75 7.773872325 Si 0.25 0.25 2.591290775 end As it is written in manual, when I am using 'surface' keyword, x and y are in fractional coordinates, whereas z is in cartesian. On output from calculations I get following cell parameters from pspw module: supercell: cell_name: cell_default lattice: a1=< 10.365 0.000 0.000 > a2=< 0.000 10.365 0.000 > a3=< 0.000 0.000 1.000 > reciprocal: b1=< 0.606 0.000 0.000 > b2=< 0.000 0.606 0.000 > b3=< 0.000 0.000 6.283 > lattice: a= 10.365 b= 10.365 c= 1.000 alpha= 90.000 beta= 90.000 gamma= 90.000 omega= 107.4 And here is the question: why 'c' equal to 1.000 au, whereas it suppose to be 10.365 ? After pspw I run band calculations and in output I have got followoing initial positions of atoms: initial position of ions: 1 Si ( 0.00000 0.00000 0.00000 ) - atomic mass= 27.977 2 Si ( 5.18258 5.18258 0.00000 ) - atomic mass= 27.977 3 Si ( 0.00000 5.18258 0.18258 ) - atomic mass= 27.977 4 Si ( 5.18258 0.00000 0.18258 ) - atomic mass= 27.977 5 Si ( -2.59129 -2.59129 -0.40871 ) - atomic mass= 27.977 6 Si ( -2.59129 2.59129 -0.22613 ) - atomic mass= 27.977 7 Si ( 2.59129 -2.59129 -0.22613 ) - atomic mass= 27.977 8 Si ( 2.59129 2.59129 -0.40871 ) - atomic mass= 27.977 G.C. ( 1.29565 1.29565 -0.11306 ) C.O.M. ( 1.29565 1.29565 -0.11306 ) which are different from those written in input. It looks like that my surface is only 1 au thick. Is it possible to make such layer 10.365 au "high", or even more, i.e. 4*10.365? And another question, what are the references for pspw and band modules? Thanks in advance. Best regards, Kuba -------------------------------------------------------------------------------- Kuba Kaminski email: qba@mml.ch.pwr.wroc.pl http://sapho.chem.uni.torun.pl/~teoqba --------------------------------------------------------------------------------