From owner-nwchem-users@emsl.pnl.gov Thu Dec 8 15:28:27 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 jB8NSQR8006881 for ; Thu, 8 Dec 2005 15:28:27 -0800 (PST) Received: (from majordom@localhost) by odyssey.emsl.pnl.gov (8.12.10/8.12.10/Submit) id jB8NSQFV006880 for nwchem-users-outgoing-0915; Thu, 8 Dec 2005 15:28:26 -0800 (PST) Date: Thu, 08 Dec 2005 15:22:52 -0800 From: "Bylaska, Eric J" Subject: RE: [NWCHEM] PSPW - Bond Constraints & TS search To: Natasha Galea , 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: [NWCHEM] PSPW - Bond Constraints & TS search thread-index: AcXxRB5GsaNEjc6OQQS3wH7zuxAuZALCiS5Q Content-class: urn:content-classes:message X-MS-Has-Attach: X-MS-TNEF-Correlator: X-OriginalArrivalTime: 08 Dec 2005 23:22:53.0067 (UTC) FILETIME=[500DFDB0:01C5FC4E] Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by odyssey.emsl.pnl.gov id jB8NSQR8006875 Sender: owner-nwchem-users@emsl.pnl.gov Precedence: bulk Natasha, A final way is to use spring constraints along with the driver module. (see section "22 Constraints for Geometry Optimization") Hope that helps Eric Bylaska -----Original Message----- From: owner-nwchem-developers@emsl.pnl.gov [mailto:owner-nwchem-developers@emsl.pnl.gov] On Behalf Of Natasha Galea Sent: Thursday, November 24, 2005 2:00 PM To: nwchem-users@emsl.pnl.gov Subject: [NWCHEM] PSPW - Bond Constraints & TS search Dear NWChem Users, I am trying to calculate the energy pathway (minima and transition states) for the adsorption of methane on a periodic copper surface (PSPW calculation). At present I am trying to constrain a bond distance within the adsorbate (to model dissociation and locate transition states), as well as keeping the copper surface coordinates frozen within the periodic supercell. I have tried several methods and run into an array of problems depending on my approach. (1) When using all internal coordinates to describe the system, the copper layers do not remain parallel to the supercell during optimization. i.e. the copper surface does not appear to remain planar. (2) When using a mixture of internal and cartesian coordinates to describe the system, only an energy calculation can be performed. When attempting an optimization calculation the program objects to the geometry. Has anyone any experience with these problems? Thanks Natasha