From owner-chemistry ^%at%^ ccl.net Thu Apr 12 16:07:01 2007
From: "Reynier Suardiaz reynier%a%fq.uh.cu" <owner-chemistry*o*server.ccl.net>
To: CCL
Subject: CCL:G: convergence problems in nmr coupling constants calculations
Message-Id: <-34034-070412151652-11271-2PFk+K/WWMRmUqkPADPBog*o*server.ccl.net>
X-Original-From: "Reynier  Suardiaz" <reynier:fq.uh.cu>
Date: Thu, 12 Apr 2007 15:16:48 -0400


Sent to CCL by: "Reynier  Suardiaz" [reynier__fq.uh.cu]
Dear CCL memebers

I am trying to calculate spin spin coupling constants (SSCC) with g03D1 with B3LYP, B3P86 functionals and aug-cc-pVTZ-J basis set funcion. I received the following error message from gaussian:

                 (A1) (B2) (A1) (B2)
 The electronic state of the initial guess is 1-A1.
 Requested convergence on RMS density matrix=1.00D-08 within 600 cycles.
 Requested convergence on MAX density matrix=1.00D-06.
 Requested convergence on             energy=1.00D-06.
 No special actions if energy rises.
 Rare condition: small coef for last iteration:  0.000D+00
 Rare condition: small coef for last iteration:  0.000D+00
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.


The geometry optimization was performed with B3LYP/6-31G**, if i performed a single point calculation with B3LYP,B3P86/aug-cc-pVTZ-J the claculation converge without problems.

the keywords for SSCC are:

 nmr=spin IOp(10/48=10) B3P86 Gen SCF=(NoVarAcc,maxcycle=600)

if i use an input like:

 nmr=spin IOp(10/48=10) B3P86 Gen 

the results are esencially the same

any suggestion or comment will be acknowledged

Best Regards

Reynier