Subject: GAUSSIAN need to clarify

From: "Zhixiang Wang" <zxwang{at}chem.udel.edu>
Date: Wed, 15 Oct 2003 14:07:34 -0400

Hi All
   I paln to study solvation free energies using gaussin. When I tried to
understand the output file and compare the output results with the manual, I
was totally confused, and found there are  discrepancies between manual and
the gaussin output file. I hope gaussian clarify this. Suggestions on how to
calculate the solvation free energies will greately appreciated. For
example, the solvatin free energy of methanol in water.

Sincerely

ZX
***********************
Details

In the current manual on web,

SCF Done:  E(RHF) =  -98.569083211     A.U. after    5 cycles
          Convg  =    0.4249D-05             -V/T =  2.0033
          S**2   =   0.0000
--------------------------------------------------------------------
Variational PCM results
=======================
<psi(f)|   H   |psi(f)>                 (a.u.) =     -98.568013
<psi(f)|H+V(f)/2|psi(f)>                (a.u.) =     -98.573228
Total free energy in solution:
 with all non electrostatic terms       (a.u.) =     -98.569083
--------------------------------------------------------------------
(Polarized solute)-Solvent               (kcal/mol) =      -3.27
--------------------------------------------------------------------
Cavitation energy                        (kcal/mol) =       5.34
Dispersion energy                        (kcal/mol) =      -3.08
Repulsion energy                         (kcal/mol) =       0.34
Total non electrostatic                  (kcal/mol) =       2.60
--------------------------------------------------------------------

 Note that the E(RHF) energy (-98.569083211) is equal to Total free energy
in solution
with all non electorstatic terms -98.569083.

While in my output file give (G03, B.04)

 SCF Done:  E(RB+HF-LYP) =  -115.736036910     A.U. after   10 cycles
             Convg  =    0.7861D-09             -V/T =  2.0067
             S**2   =   0.0000
 KE= 1.149665200488D+02 PE=-3.519462956324D+02 EE= 8.102355096224D+01
 --------------------------------------------------------------------
 Variational PCM results
 =======================
 <psi(f)|   H    |psi(f)>                     (a.u.) =    -115.727169
 <psi(f)|H+V(f)/2|psi(f)>                     (a.u.) =    -115.736037
 Total free energy in solution:
  with all non electrostatic terms            (a.u.) =    -115.728593
 --------------------------------------------------------------------
 (Polarized solute)-Solvent               (kcal/mol) =      -5.56
 --------------------------------------------------------------------
 Cavitation energy                        (kcal/mol) =       9.54
 Dispersion energy                        (kcal/mol) =      -5.23
 Repulsion energy                         (kcal/mol) =       0.36
 Total non electrostatic                  (kcal/mol) =       4.67
 --------------------------------------------------------------------

here E(RB+HF-LYP) (-115.736036910)= <psi(f)|H+V(f)/2|psi(f)>(-115.736037)

I also note that the manual printed out on Aug.11/03 tell me thia

SCF Done:  E(RHF) =  -100.02918740     A.U. after    5 cycles
          Convg  =    0.4249D-05             -V/T =  2.0033
          S**2   =   0.0000
--------------------------------------------------------------------
Variational PCM results
=======================
<psi(f)|   H   |psi(f)>                 (a.u.) =     -98.568013
<psi(f)|H+V(f)/2|psi(f)>                (a.u.) =     -98.573228
Total free energy in solution:
 with all non electrostatic terms       (a.u.) =     -98.569083
--------------------------------------------------------------------
(Polarized solute)-Solvent               (kcal/mol) =      -3.27
--------------------------------------------------------------------
Cavitation energy                        (kcal/mol) =       5.34
Dispersion energy                        (kcal/mol) =      -3.08
Repulsion energy                         (kcal/mol) =       0.34
Total non electrostatic                  (kcal/mol) =       2.60
--------------------------------------------------------------------

The E(RHF) energy (-100.02918740) is neither equal to
<psi(f)|H+V(f)/2|psi(f)> energy nor to Total free energy in solution: with
all non electrostatic terms.