From owner-chemistry@ccl.net Sun Nov 11 14:55:01 2012 From: "LUIS FERMIN RODRIGUEZ VAZQUEZ luisfer:_:edu.xunta.es" To: CCL Subject: CCL:G: Strange energies for Gaussian IRC calculation Message-Id: <-47874-121111054102-20472-CvfYaKjXDQt5ufTCxTAHLA#%#server.ccl.net> X-Original-From: LUIS FERMIN RODRIGUEZ VAZQUEZ Content-Disposition: inline Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=ISO-8859-1; DelSp="Yes"; format="flowed" Date: Sun, 11 Nov 2012 11:40:51 +0100 MIME-Version: 1.0 Sent to CCL by: LUIS FERMIN RODRIGUEZ VAZQUEZ [luisfer|*|edu.xunta.es] Dear Ivo Jacobs. In your input i am which has not indicated the number of stages that must be calculated in your problem, in which the program has been calculated only 5 or 6 points. This is indicated with "MaxPoint= ". Nor has it indicated the step size in each stage by which the program has taken this value by default. It should be "stepsize= ". I see that nor has it indicated the basis set of calculation. I recommend that you use a line of input as well: # irc= (both,maxpoints=500,calcfc,maxcyc=500,stepsize= 5) rb3LYP/ 6-31++g(d,p) so it should get its complete calculation. If you have a problem, do not hesitate to contact me. A greeting. -- ------------------------------------------------- LUIS F. R. VÁZQUEZ DEP. QUÍMICA FARMACÉUTICA GRUPO DE QUÍMICA TEÓRICA Y COMPUTACIONAL-DISEÑO DE FÁRMACOS Rúa Alfredo Vicenti, 43 - 4 15004-A CORUÑA-GALICIA-SPAIN Tel. +34 981 150 355 - móbil. +34 676 300 472 E-mail. luisfer^edu.xunta.es ------------------------------------------------ ----- Mensaxe de owner-chemistry^ccl.net --------- Data: Sat, 10 Nov 2012 15:42:37 -0500 De: "Ivo Jacobs jacobs.ivo^gmail.com" Responder-A:CCL Subscribers Asunto: CCL:G: Strange energies for Gaussian IRC calculation Para: "Rodriguez, Luis Fermin " > > Sent to CCL by: "Ivo Jacobs" [jacobs.ivo[a]gmail.com] > Hello, > > I have started to do some IRC calculations with Gaussian '03, but it > gives me very strange results. > I have previously located a transition state, done the frequency > analysis, and it's a true saddle point, energy is -1706 Hartree. For > the IRC calculation, my input looks like this: > > %NProcShared=4 > %NProcLinda=1 > %mem=2000MB > %chk=checkpnt.chk > #P TEST IRC=(FORWARD,RCFC) B3LYP CHKBASIS GEOM=CHECKPOINT GUESS=READ > > Title > > 0 1 > > This initially seems to work very slowly (SCF needs more than 40 > cycles to converge, which is much more than I have typically seen > before), but more problematically, the energies are wildly different > (-3127 Hartree on the first cycle, same order of magnitude for the > later ones). If I do a single point energy starting from the > original transition state checkpoint file, the SCF finishes in one > cycle with -1706 Hartree, so the problem is not in the checkpoint > file. I've tried to repeat the IRC calculation with CalcAll or with > CalcFC, and this gives the same problem. Also without using > "Guess=Read" the same result is obtained. It looks to me like the > initial reading of the guess fails for some reason. Anybody any idea > what is going on here? > > Thanks in advance, > Ivo Jacobs> > > ----- Rematar mensaxe de owner-chemistry^ccl.net ----- From owner-chemistry@ccl.net Sun Nov 11 17:22:00 2012 From: "Ivo Jacobs jacobs.ivo/a\gmail.com" To: CCL Subject: CCL: Strange energies for Gaussian IRC calculation Message-Id: <-47875-121111172051-18400-XYVgB2RjeYZeuKEuwYdl4g[]server.ccl.net> X-Original-From: Ivo Jacobs Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1; format=flowed Date: Sun, 11 Nov 2012 23:20:40 +0100 MIME-Version: 1.0 Sent to CCL by: Ivo Jacobs [jacobs.ivo||gmail.com] Dear Luis, I think that the points that you bring forward are not the cause of my problem. I tried to specify "MAXPOINTS=500" and "STEPSIZE=5", but it gave the same unreasonably low energy. The basis set is specified by the "CHKBASIS" keyword. This reads the basis set from the checkpoint file, which is quite convenient in this case since I'm using different basis sets for different parts of my system. Thank you for the suggestions, Ivo On 11/11/12 11:40 AM, LUIS FERMIN RODRIGUEZ VAZQUEZ luisfer:_:edu.xunta.es wrote: > > Sent to CCL by: LUIS FERMIN RODRIGUEZ VAZQUEZ [luisfer|*|edu.xunta.es] > Dear Ivo Jacobs. In your input i am which has not indicated the number > of stages that must be calculated in your problem, in which the > program has been calculated only 5 or 6 points. This is indicated with > "MaxPoint= ". Nor has it indicated the step size in each stage by > which the program has taken this value by default. It should be > "stepsize= ". I see that nor has it indicated the basis set of > calculation. > I recommend that you use a line of input as well: > > # irc= (both,maxpoints=500,calcfc,maxcyc=500,stepsize= 5) rb3LYP/ > 6-31++g(d,p) > > so it should get its complete calculation. If you have a problem, do > not hesitate to contact me. > > A greeting. > >