From owner-nwchem-users@emsl.pnl.gov Mon Feb 20 11:07:14 2006 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 k1KJ7E0O025738 for ; Mon, 20 Feb 2006 11:07:14 -0800 (PST) Received: (from majordom@localhost) by odyssey.emsl.pnl.gov (8.12.10/8.12.10/Submit) id k1KJ7Esi025737 for nwchem-users-outgoing-0915; Mon, 20 Feb 2006 11:07:14 -0800 (PST) Date: Mon, 20 Feb 2006 11:07:11 -0800 From: "Bylaska, Eric J" Subject: [NWCHEM] RE: Question on NWPW of Nwchem To: limin Cc: nwchem-users@emsl.pnl.gov Message-id: MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-type: text/plain; charset=us-ascii Thread-Topic: Question on NWPW of Nwchem Thread-Index: AcYyIuJZDSkUuh/jSASJOrGjnSaHzwEK74kw Content-class: urn:content-classes:message X-MS-Has-Attach: X-MS-TNEF-Correlator: X-OriginalArrivalTime: 20 Feb 2006 19:07:12.0870 (UTC) FILETIME=[DB273060:01C63650] Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by odyssey.emsl.pnl.gov id k1KJ7D0O025734 Sender: owner-nwchem-users@emsl.pnl.gov Precedence: bulk Dr. Liu, Here's the answers to your questions. 1. If you're just running a single Li atom the code will automatically assign it a multiplicity of 2 (doublet) as an unrestricted calculation. You can directly specify the multiplicity for the atom by nwpw mult 2 odft end If you want to run the Li2 dimer as unrestricted, then use nwpw mult 1 odft end 2. The units of cutoff energy is in au or Hartrees, and the fft grid is always specified from ngrid. If you don't specify the cutoff energy then the code will use the largest possible cutoff energy for the specified grid. 3. As a general rule of thumb the smaller the band-gap in your system the larger the cell/(number of k-points) you need to use. There is a limited band-structure cabability in nwchem-4.7 (BAND module, see section 35.2 of the NWChem users manual). The BAND module is still under major development, and several new cababilities will be made available in the next release. Eric Bylaska -----Original Message----- From: limin [mailto:limin@fhi-berlin.mpg.de] Sent: Wednesday, February 15, 2006 3:28 AM To: Bylaska, Eric J Subject: Question on NWPW of Nwchem Dear Eric J. Bylaska, I am a new user of NWPW of Nwchem and very like this code. I have several questions to inquire you. 1. I want to use NWPW to calcuate the cohesive energy of bulk Li. At first, I want to know how can I set the spin-polarlized for a single Li atom? Which key word do I need to use: ODFT or MULT? 2. It seems that NWPW uses both ngrid and energy_cutoff to decide the FFT. The unit of energy_cutoff is Ry or Hartree or ev? If I set both the ngrid and energy_cutoff, which one will be used? 3.PSPW does not use k-piont for the crystal . I want to know whether this is accurate for the small system? for example, I want to calcuate the lattice constant of LiF ( exp. 4.02 Ang). Can I just use the small cell of 4.02A*4.02*4.02 to study the lattice constant? Best Regards, Limin -------------------------------------------------------------------- Dr Limin Liu Phone: (+49 30) 8413-4864 Fritz-Haber-Institut Fax: (+49 30) 8413-4701 der Max-Planck-Gesellschaft WWW: www.fhi-berlin.mpg.de/th Faradayweg 4-6 E-Mail: limin@fhi-berlin.mpg.de D-14195 Berlin, Germany