From KGRAFTON@aardvark.ucs.ou.edu Thu Aug 29 00:51:15 1996 Whoops. In the mail I sent you earlier, I said we had tried G2 on quinone energies. That was a bit wrong. We sis try it, but did not have the computing resources to complete the jobs (which includes an 8 processor IBM/SP2 with 512MB/processor). The method that we did use and get poor results from was the CBS-4 calculation. Sorry about the confusion. Anthony Grafton Department of Chemistry University of Oklahoma -- From: "Frederick R. Bennett" Subject: CCL:G:G2 with reduced basis sets Hi, someone was asking about attempting G2 calculations with reduced basis sets. Well I found a paper addressing this issue exactly Gaussian-2 (G2) theory: Reduced basis set requirements, Curtis, Redfern, Smith, and Radom: JCP, 104 (13) 5184 Hope this helps Ciao =============================================================================== Frederick R. Bennett Papernet Address: Institut Fur anorganische, analytische und physikalische Chemie Freiestrasse 3 CH-3000 Bern 9 Switzerland Mouthnet Address: [41] (031) 631 4231 Faxnet Address [41] (031) 631 3994 Internet Address: bennett@ubeclu.unibe.ch =============================================================================== From: Anthony P Scott (also thanks to James W Gauld ) Jeremy, I understand that James has already sent you two references for the G2(MP2,SVP) method. Here are the two leading references for G2(MP2,SVP). Smith, B. J. and Radom, L. J. Phys. Chem. 99 (1995) 6468. - where it is first introduced Curtiss, L. A., Redfern, P. C., Smith, B. J. and Radom, L. J. Chem. Phys. 104 (1996) 5148. - a detailed description of G2(MP2,SVP), including the new HLC to use. In your email you didn't say why the qcisd(t)/6-311g** calculataions are not possible. Is it disk space or cpu time that limits you? If you are trying to do these calculations with Gaussian you are really beating your head against a brick wall. Two other programs are substantially more efficient that G94 for these type of calculations. Molpro96 ( limited to closed shell however) or ACES2 will result in (usually) much better cpu times that G94. They both make explicit use of symmetry, however ACES2 in C1 symmetry will often take longer than gaussian!! If it is disk space that is the problem then try to get more! Hope this is of some use. Kind Regards, Tony --