Subject: G98: VOCl3 problem: convergence criterion not met

From: Rudolf Herrmann <[email-masked]>
Date: Mon, 14 Oct 2002 19:15:13 +0100 (WEST)

Hello,
I recently tried to calculate the NMR chemical shifts of VOCl3
with Gaussian 98:
----------------------------------------------------------------------------
#B3LYP/6-31G* SP NMR

VOCl3

0 1
cl
cl   1 clcl2
cl   2 clcl3      1 clclcl3
 o   3 ocl4       2 oclcl4       1 dih4
 v   3 vcl5       2 vclcl5       1 dih5

clcl2       3.506363
clcl3       3.506243
clclcl3      59.999
ocl4        2.938735
oclcl4       53.376
dih4        -64.586
vcl5        2.118170
vclcl5       34.144
dih5        -31.640
-----------------------------------------------------------------------------
The result (even with several variations in the input) is always an
error termination when trying the "incremental Fock formation"
(convergence criterion not met). The structure was optimized with
GAMESS. 
Any suggestion what I could do is wellcome - thank you!
------------------------------------------------------------------------------
   108 basis functions      288 primitive gaussians
    41 alpha electrons       41 beta electrons
       nuclear repulsion energy       561.9817715949 Hartrees.
 One-electron integrals computed using PRISM.
 NBasis=   108 RedAO= T  NBF=   108
 NBsUse=   108 1.00D-04 NBFU=   108
 Projected Huckel Guess.
 Requested convergence on RMS density matrix=1.00D-08 within  64 cycles.
 Requested convergence on MAX density matrix=1.00D-06.
 Virtual orbitals will be shifted by   0.200 hartree.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 Restarting incremental Fock formation.
 >>>>>>>>>> Convergence criterion not met.
 SCF Done:  E(RB+HF-LYP) =  -2359.59549049     A.U. after   65 cycles
             Convg  =    0.5851D-03             -V/T =  1.9657
             S**2   =   0.0000
 Convergence failure -- run terminated.
 Error termination via Lnk1e in /usr/local/g98_a7/l502.exe.
 Job cpu time:  0 days  0 hours 16 minutes 33.0 seconds.
 File lengths (MBytes):  RWF=   14 Int=    0 D2E=    0 Chk=    1 Scr=    1
--------------------------------------------------------------------------
-- 
Dr. Rudolf Herrmann
Instituto de Tecnologia Quimica e Biologica (ITQB)
Av. da Republica, EAN,  Apt. 127
P-2781-901 Oeiras
e-mail: [email-masked]