Subject: Atomic Charges (GAMESS 93 vs. GAUSSIAN 92)!

From: Alexandre <[email-masked]>
Date: Wed, 26 Jan 1994 19:23:49 -0300 (GMT-3:00)

Hello!

     I did a RHF/STO-3G geometry optimization in HCl, using GAUSSIAN 92.
Then, I did a Mulliken population analysis, using GAUSSIAN 92. But, when
I did the same calculation, using GAMESS 93, the Mulliken net charges were
not the same! Why? I did the optimization geometry only with GAUSSIAN 92!

    *The GAUSSIAN 92 Input/Output is:

----------------------------------------------------
INPUT:
------

$rungauss
#n rhf/sto-3g pop=reg

... HCl ... RHF/STO-3G

0 1
H
Cl 1 r

r 1.31333495

----------------------------------------------------
OUTPUT:
-------

ENERGY: HF=-455.1360117

                   Standard orientation:
 ----------------------------------------------------------
 Center     Atomic              Coordinates (Angstroms)
 Number     Number             X           Y           Z
 ----------------------------------------------------------
    1          1            .000000     .000000   -1.240372
    2         17            .000000     .000000     .072963
 ----------------------------------------------------------

 Total atomic charges:
              1
  1  H     .173622
  2  Cl   -.173622
 Sum of Mulliken charges=    .00000
----------------------------------------------------

    *The GAMESS 93 Input/Output is:

----------------------------------------------------
INPUT:
------

 $CONTRL UNITS=ANGS $END
 $SYSTEM MEMORY=2000000 $END
 $BASIS GBASIS=STO NGAUSS=3 $END
 $DATA
... HCl ... RHF/STO-3G ...
C1
H          1             .000000     .000000   -1.240372
Cl         17            .000000     .000000     .072963
 $END
-----------------------------------------------------
OUTPUT:
-------

ENERGY: E(RHF) =  -455.136011655

          TOTAL MULLIKEN AND LOWDIN ATOMIC POPULATIONS
       ATOM         MULL.POP.    CHARGE          LOW.POP.     CHARGE
    1 H              .869767     .130233          .920083     .079917
    2 CL           17.130233    -.130233        17.079917    -.079917
-----------------------------------------------------

     Note that I used the same geometry in both calculations! And, in fact,
the energy was practly the same! But the Mulliken charges...

     Does it represent a bug in GAMESS 93?

     Thanks!

------------------------------------
Alexandre Araujo de Souza.
Universidade Estadual de Campinas
Brazil. E-mail: [email-masked]
------------------------------------