Subject: solvation question regarding PCM techniques in G98 and G03

From: khunter..at..mta.ca
Date: Wed, 5 May 2004 14:01:38 -0300

Upon doing a solvation calculation using the following command prompt, 
#b3lyp/6-31g(d,p) opt SCRF=(IEFPCM, solvent=water),  with the Gaussian 98 
suite the calculation would run to completion but would list an Error message 
such as shown below.  (With emphasis on Error on NUCLEAR pol.charges)

 Two-electron integral symmetry is turned on.
   215 basis functions      385 primitive gaussians
    43 alpha electrons       43 beta electrons
       nuclear repulsion energy       693.2194006859 Hartrees.
 One-electron integrals computed using PRISM.
 NBasis=   215 RedAO= T  NBF=   215
 NBsUse=   215 1.00D-04 NBFU=   215
 Projected INDO Guess.
 Requested convergence on RMS density matrix=1.00D-08 within  64 cycles.
 Requested convergence on MAX density matrix=1.00D-06.
 ----------------------------------------------------------------------
 Solvent: WATER
 Model  : IEF/UAHF, Icomp = 0
 Version: MATRIX INVERSION
 Cavity : PENTAKISDODECAHEDRA with  60 initial tesserae
 ----------------------------------------------------------------------
 Nord Group  Hybr  Charge Alpha Radius            Bonded to
   1   N     sp2   0.00   1.20  1.590     C2  [s]  C5  [s]  C12 [s]
   2   C     sp3   0.00   1.20  1.500     N1  [s]  C3  [s]  N9  [s]
   3   C     sp3   0.00   1.20  1.500     C2  [s]  N4  [s]  C6  [s]
   4   N     sp2   0.00   1.20  1.590     C3  [s]  C5  [d]
   5   CH    sp2   0.00   1.20  1.860     N1  [s]  N4  [d]
   6   C     sp2   0.00   1.20  1.635     C3  [s]  N7  [s]  O11 [d]
   7   NH    sp2   0.00   1.20  1.680     C6  [s]  C8  [s]
   8   C     sp2   0.00   1.20  1.680     N7  [s]  N9  [d]  N10 [s]
   9   N     sp2   0.00   1.20  1.590     C2  [s]  C8  [d]
  10   NH2   sp3   0.00   1.20  1.680     C8  [s]
  11   O     sp2   0.00   1.20  1.590     C6  [d]
  12   CH3   sp3   0.00   1.20  1.860     N1  [s]
 ----------------------------------------------------------------------
 Warning: nuclear charge 211 neglected
 Warning: electronic charge 211 neglected
     FIRST ITERATION
 Error on NUCLEAR pol.charges = 0.02091 Error on ELECTR. pol.charges =-0.03449

Upon doing a similar calculation using the Gaussian 03 suite but with  
#b3lyp/6-31g(d,p) opt SCRF=(PCM, solvent=water) as the command prompt, due to 
the alteration in the solvation methods, the calculation would end up going 
into a loop of optimization cycles and fail due to exceeding the number of 
optimization steps.  Besides the error of exceeding the number of optimization 
steps, an Error comment would appear before the SCF stating : Error on total 
polarization charges = 0.01117

My questions are does the error produced in the Gaussian 98 significant and 
how to correct the error in the Gaussian 03 suite and why the different errors?

Ken Hunter