From owner-chemistry@ccl.net Wed Jan 18 06:34:00 2012 From: "Georg Lefkidis lefkidis!=!physik.uni-kl.de" To: CCL Subject: CCL:G: AW: G09: CASSCF warning Message-Id: <-46158-120118062951-2559-JSfeA78kOgd9k7u4iZ8KCA],[server.ccl.net> X-Original-From: "Georg Lefkidis" Content-Language: de Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="iso-8859-1" Date: Wed, 18 Jan 2012 12:29:41 +0100 MIME-Version: 1.0 Sent to CCL by: "Georg Lefkidis" [lefkidis||physik.uni-kl.de] Dear Vera, although I do not have all the information from your com file, I suspect degeneracy (or quasi) here. This means that Gaussian is trying to lower the energy and in every iteration there is a level crossing leading to convergence-oscillations (in other words every iteration tries to lower the energy of a different molecular orbital confusing Gaussian). The way to avoid that is to identify the levels that cause the problem and have CASSCF minimize the energy for both (or all) of them *at the same time*. Use the StateAverage option do to so. I hope this helps (it has for me in the past!) Best regards George -----Ursprüngliche Nachricht----- Von: owner-chemistry+lefkidis==physik.uni-kl.de.],[.ccl.net [mailto:owner-chemistry+lefkidis==physik.uni-kl.de.],[.ccl.net] Im Auftrag von Vera Cathrine vera.cathrine a yahoo.com Gesendet: Mittwoch, 18. Januar 2012 11:39 An: Lefkidis, Georg Betreff: CCL: G09: CASSCF warning Sent to CCL by: "Vera Cathrine" [vera.cathrine^_^yahoo.com] Dear All, I am running a CASSCF calculations. G09 issues a warning regarding the large rotation of orbitals as shown in the following. I already know that this warning signify that the orbitals are not good starting orbitals which indicates that there could be problems. However if this occurs only at the first steps of the wave-function optimization and the energy converges smoothly it seems that this warning is not fatal. However, I dont know how these warnings can help me to find the correct orbitals or how to fix the warning at all? Any general guide is greatly appreciated. Best regards, Vera WARNING! : large rotation I J = 48 38 Step scaled by 9.8286815811546094E-002 ITN= 1 MaxIt= 64 E= -637.5621751557 DE=-6.38D+02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 49 48 Step scaled by 0.1039006628670738 ITN= 2 MaxIt= 64 E= -637.5029804099 DE= 5.92D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 49 35 Step scaled by 0.1427849527680300 ITN= 3 MaxIt= 64 E= -637.4932393622 DE= 9.74D-03 Acc= 1.00D-08 Lan= 0 ITN= 4 MaxIt= 64 E= -637.4865343884 DE= 6.70D-03 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 49 48 Step scaled by 0.7380582824594381 ITN= 5 MaxIt= 64 E= -637.4176733760 DE= 6.89D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 48 35 Step scaled by 0.2877574555342823 ITN= 6 MaxIt= 64 E= -637.3770255363 DE= 4.06D-02 Acc= 1.00D-08 Lan= 0 ITN= 7 MaxIt= 64 E= -637.3086594950 DE= 6.84D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 53 50 Step scaled by 0.4846317462914080 ITN= 8 MaxIt= 64 E= -637.3137340085 DE=-5.07D-03 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 53 50 Step scaled by 0.5107805781250911 ITN= 9 MaxIt= 64 E= -637.2887888967 DE= 2.49D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 48 23 Step scaled by 0.3154420167117161 ITN= 10 MaxIt= 64 E= -637.2275618744 DE= 6.12D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 48 23 Step scaled by 0.8747886194178708 ITN= 11 MaxIt= 64 E= -637.2166647016 DE= 1.09D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 54 50 Step scaled by 0.8117438649098225 ITN= 12 MaxIt= 64 E= -637.2032627261 DE= 1.34D-02 Acc= 1.00D-08 Lan= 0 WARNING! : large rotation I J = 54 50 Step scaled by 4.5686553052688081E-002 ITN= 13 MaxIt= 64 E= -637.1542499631 DE= 4.90D-02 Acc= 1.00D-08 Lan= 0http://www.ccl.net/cgi-bin/ccl/send_ccl_messagehttp://www.ccl.net/chemistry/sub_unsub.shtmlhttp://www.ccl.net/spammers.txt