From owner-chemistry@ccl.net Fri Nov 8 07:55:00 2013 From: "Susi Lehtola susi.lehtola\a/alumni.helsinki.fi" To: CCL Subject: CCL: SCF convergence failure with AUG-cc-pVDZ basis in Gaussian 09 Message-Id: <-49320-131108074725-11850-CEZwxBBwQslan8Br+MYnQA]-[server.ccl.net> X-Original-From: Susi Lehtola Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Date: Fri, 8 Nov 2013 14:47:17 +0200 Mime-Version: 1.0 Sent to CCL by: Susi Lehtola [susi.lehtola,+,alumni.helsinki.fi] On Thu, 7 Nov 2013 20:16:14 +0200 "Susi Lehtola susi.lehtola(_)alumni.helsinki.fi" wrote: > Also, it occurred to me that you are not using density fitting (a.k.a. > RI-J). If you use pure DFT functionals (e.g. PBEPBE and BP86), enabling > density fitting usually speeds up the calculation quite a bit. Also, > AFAIK incremental formation is not usually performed in RI-J, since the > integrals are much faster to compute anyway, so you might not need the > NoIncFock keyword. To do RI-J just change > #P PBEPBE/aug-cc-pVDZ > to > #P PBEPBE/aug-cc-pVDZ/Auto > which will use an automatically generated fitting basis set. This indeed does converge the anthracene run without any problems, while the conventional calculation (without RI-J) requires SCF=NoIncFock to converge. Interestingly, the RI-J calculation takes 19 cycles to converges whereas the conventional calculation converges in 13 cycles. But the RI-J run is still 3 times faster - and this was for aug-cc-pVDZ, for bigger basis sets it'll be even faster in comparison. -- --------------------------------------------------------------- Mr. Susi Lehtola, PhD Research Associate susi.lehtola^^alumni.helsinki.fi Department of Applied Physics http://www.helsinki.fi/~jzlehtol Aalto University Finland --------------------------------------------------------------- Susi Lehtola, FT Tutkijatohtori susi.lehtola^^alumni.helsinki.fi Fysiikan laitos http://www.helsinki.fi/~jzlehtol Aalto-yliopisto ---------------------------------------------------------------