From owner-chemistry@ccl.net Sun Aug 31 22:45:00 2008 From: "Brian Salter-Duke brian.james.duke|a|gmail.com" To: CCL Subject: CCL:G: Pure vs. Cartesian Basis Functions Message-Id: <-37690-080831214413-14923-taquGaRCuZgQZdOp2wtNPA^_^server.ccl.net> X-Original-From: Brian Salter-Duke Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8; format=flowed Date: Mon, 01 Sep 2008 11:43:52 +1000 MIME-Version: 1.0 Sent to CCL by: Brian Salter-Duke [brian.james.duke\a/gmail.com] Fu-Ming Ying fmying * gmail.com wrote: > > Sent to CCL by: Fu-Ming Ying [fmying||gmail.com] > > hej > I don' think the result will differ much for geometry optimization. > But if you'd better use the same type during all the calculations. > For example, if you use 5D in hf/3-21G, then I think it's better to use > 5D in b3lyp/6-31++G(D,P) etc. I think this misses the point. You should use the appropriate type that the basis set is defined for. Look at the defined defaults in the manual - pg 27 for G03 manual. 3-21G and 6-31G use 6D, while 6-311G uses 5D. If you go from 6-31G to 6-311G you should stick to the defaults, changing > from 6D to 5D. Brian. > gnli gnli,dicp.ac.cn wrote: >> >> *Dear CCLer,* >> >> *Please forgive me for my simple question.* >> >> *Is it necessary to keep the basis set to be Pure or Cartesian type >> during all the calculate step in one system?* >> >> *For example, we optimize a molecule using “hf/3-21g hf/6-31g >> b3lyp/6-31g b3lyp/6-31++g(d,p) b3lyp/aug-cc-pvdz” gradually, need we >> define the Basis Functions all in 5D 7F or 6D 10F in the route section >> consistently, or just using default? Is the difference serious? * >> >> *Thanks!* >> >> best wishes >> Guanna Li >> gnli]|[dicp.ac.cn >> -- Brian Salter-Duke (Brian Duke) Brian.James.Duke(a)gmail.com Post: 626 Melbourne Rd, Spotswood, VIC, 3015, Australia http://www.salter-duke.bigpondhosting.com/brian/index.htm Honorary Researcher Fellow, Monash Institute of Pharmaceutical Sciences