From owner-chemistry@ccl.net Tue Sep 22 21:34:01 2015 From: "Ray Merewether Ray.Merewether-#-seescan.com" To: CCL Subject: CCL: Constructive DFT suggestions appreciated Message-Id: <-51772-150922194650-20017-DOdPtMNg4UTE9qECz8C22w-x-server.ccl.net> X-Original-From: Ray Merewether Content-Language: en-US Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="utf-8" Date: Tue, 22 Sep 2015 23:46:42 +0000 MIME-Version: 1.0 Sent to CCL by: Ray Merewether [Ray.Merewether|*|seescan.com] Alan, Here is a paper from 2012: Why the Standard B3LYP/6-31G* Model Chemistry Should Not Be Used in DFT Calculations of Molecular Thermochemistry: Understanding and Correcting the Problem Holger Kruse†, Lars Goerigk‡, and Stefan Grimme*§ J. Org. Chem., 2012, 77 (23), pp 10824–10834 DOI: 10.1021/jo302156p Hope it helps. At the very least it is a place to start. -----Original Message----- > From: owner-chemistry+ray_merewether==deepsea.com#,#ccl.net [mailto:owner-chemistry+ray_merewether==deepsea.com#,#ccl.net] On Behalf Of Susi Lehtola susi.lehtola!^!alumni.helsinki.fi Sent: Tuesday, September 22, 2015 3:49 PM To: Ray Merewether Subject: CCL: Constructive DFT suggestions appreciated Sent to CCL by: Susi Lehtola [susi.lehtola###alumni.helsinki.fi] On 09/22/2015 02:31 PM, Alan Shusterman alan=-=reed.edu wrote: > I have read several CCL messages over the past few weeks disparaging a > correspondent's choice of DFT functional (usually B3LYP, but not > always) as being obsolete, useless, or both. > > These are perfectly fair opinions to share, but they are not constructive. > If you want to disparage a computational approach, fine with me, but > please recommend at least *one* better alternative. I would like to > learn what you think I should use, not just what I should not use. > > You don't need to cite publications or explain why you prefer a > particular functional. I can look that up once you tell me which > functional(s) you think are worthy. This is certainly true. However, this *is* the computational chemistry list, and most of the people here are scientists. The main duty of a scientist is keep up to date with current methodology. Or, at least do a literature search when someone tells you your method is outdated and that you can get much better results with the same resources by using more modern techniques, as has been pointed out (even with some suggestions for alternatives) by many people on the forum. Unlike in the B3LYP/6-31G* days, where all you had was a hammer so every problem started to look like nails, today there are specialized methodologies for each field so general advice is harder to give, and so the responsibility really rests on the researcher. [We wouldn't even be in the current jam if article reviewers were more strict about the use of obsolete methodologies, but at that stage it is somewhat too late. The reviewers might also not be computational chemists.] -- ----------------------------------------------------------------------- Mr. Susi Lehtola, PhD Chemist Postdoctoral Fellow susi.lehtola=alumni.helsinki.fi Lawrence Berkeley National Laboratory http://www.helsinki.fi/~jzlehtol USA -----------------------------------------------------------------------http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt