CCL:G: ONIOM Optimization

From: "Ajanta Deka" <ajanta[]tezu.ernet.in>
Subject: CCL:G: ONIOM Optimization
Date: Mon, 13 Jul 2009 08:10:23 -0400
 Sent to CCL by: "Ajanta  Deka" [ajanta*tezu.ernet.in]
 Dear All,
 I am trying to do an optimzation using ONIOM method (Gaussian 03)for
 faujasite zeolite. For the QM part I am using uB3LYP/6-31g(d,p) and
 uB3LYP/LanL2dz and UFF for the MM part. I observe something strange in the
 output. When I look at the energy values in the subsequent steps of
 optimization, this is what I find
 SCF Done:  E(UB+HF-LYP) =  -2190.15693744     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15700719     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15693744     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15700718     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15693745     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15700721     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15693745     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15700720     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15693744     A.U. after   24 cycles
 SCF Done:  E(UB+HF-LYP) =  -2190.15700718     A.U. after   24 cycles
 Thus, the energy is approaching two different values.
 Ultimately, the job fails with the following messaqe
 Error termination request processed by link 9999.
 Error termination via Lnk1e in /home/ramesh/g03/l9999.exe at Sat Jul 11
 18:01:11 2009
 Job cpu time:  6 days 21 hours 53 minutes  6.0 seconds.
 File lengths (MBytes):  RWF=    100 Int=      0 D2E=      0 Chk=     20
 Scr=      1
 I have tried by changing the initial geometry slightly, but I get the same
 result. I have successfully got the optimized geometry for a similiar
 system (with slightly different charge). I do not know how to overcome
 this error. Please help me.
 with warm regards,
 Ajanta Deka