From jkaszuba@slate.Mines.EDU Sat Jan 18 12:17:14 1997 Received: from slate.Mines.EDU for jkaszuba@slate.Mines.EDU by www.ccl.net (8.8.3/950822.1) id LAA14128; Sat, 18 Jan 1997 11:57:47 -0500 (EST) Received: by slate.Mines.EDU (AIX 3.2/UCB 5.64/4.03) id AA55465; Sat, 18 Jan 1997 09:57:47 -0700 Date: Sat, 18 Jan 1997 09:57:47 -0700 (MST) From: "John P. Kaszuba" To: Computational Chemistry List Cc: jkaszuba@slate.Mines.EDU Subject: Ab Initio calculations on SiO2 Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII List Members, We are using CRYSTAL92 to look at SiO2 polymorphs. For alpha quartz we calculate a minimum energy at a unit cell volume that is larger than it should be. We are using 3-21G* on Si and 6-21G* on oxygen. Although we are increasing the sophistication of our basis set on Si, I can't help but wonder if the error is tied into a problem with electron correlation. Also, I read in the archives from the past few months about the 0.893 scale factor for frequency calculations. Corrections were applied to the final calculated frequencies. I figure our problem is related. But I'm thinking in our case it would be appropriate to fiddle with the "Pople scale factor" that is a part of the basis set input. Any comments or suggestions? Thank you ************************************************ John P. Kaszuba Department of Geology and Geological Engineering Colorado School of Mines Golden, Colorado 80401 phone: (303) 273-3066 fax: (303) 273-3859 email: jkaszuba@mines.edu ************************************************ From lankau@blubber.chemie.uni-hamburg.de Sat Jan 18 14:17:13 1997 Received: from blubber.chemie.uni-hamburg.de for lankau@blubber.chemie.uni-hamburg.de by www.ccl.net (8.8.3/950822.1) id NAA14387; Sat, 18 Jan 1997 13:24:03 -0500 (EST) Received: by blubber.chemie.uni-hamburg.de (AIX 4.1/UCB 5.64/4.03) id AA15250; Sat, 18 Jan 1997 19:22:04 +0100 Date: Sat, 18 Jan 1997 19:22:03 +0100 (NFT) From: Timm Lankau To: Frage CCL Subject: symmetry in G94 Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Dear collegues, I would like to reduce the symmetry of a Pt-Dimer from Dinfh to Cinfv for a single point calculation. Is there a way to tag one 'Pt' in such a way, that G94 recognizes the symmetry of the dimer as Cinfv? In cse of public interest I am going to send a summary to the list. Thank you very much. Best wishes Timm ========================================================================== Timm Lankau phone (+)40 4123 3686 Institut fuer Physikalische Chemie fax (+)40 4123 3452 Universitaet Hamburg e-mail lankau@chemie.uni-hamburg.de Bundesstr. 45 20146 Hamburg Germany