Subject: field gradient

From: <[email-masked]>
Date: Mon, 6 Dec 1993 16:38:42 +0100

Dear Netters,

I tell my questin to all people who have worked with Gaussian. 
When I use the option "grid" (for example), Gaussian gives on
output the field gradient on the different atom centers (in
which unit ??). Why is the eigenvalues' sum (for a given atom)
not equal to zero ???

For example. I am working on a molecule containing  vanadium atom,
and I try to find the field gradient on the vanadium. Gaussian gave
me the following results.

For atom 1(vanadium) I have a result completely different to zero.

 -------------------------------------------------------------------
    Center                       ---- Electric Field Gradient ----
                                 ----       Eigenvalues       ----
 -------------------------------------------------------------------
    1 Atom        -34878.093029      -34877.662053      -34877.005490
    2 Atom        -10075.766137      -10073.561024      -10073.518415
    3 Atom          -981.341478        -980.991774        -980.374420
    4 Atom          -978.570332        -977.083391        -975.947076
    5 Atom          -979.633671        -977.776480        -977.080866
    6 Atom          -394.238175        -393.654034        -393.536365
    7 Atom          -394.412704        -393.689544        -393.595338
    8 Atom            -1.922604          -1.432648          -1.419406
    9 Atom            -1.921059          -1.419987          -1.407123
   10 Atom            -1.913598          -1.425932          -1.400456
   11 Atom            -1.917686          -1.425180          -1.405185
   12 Atom        -34878.078702      -34877.646777      -34876.986685
   13 Atom        -10075.776626      -10073.564680      -10073.518593
   14 Atom          -981.340903        -980.988544        -980.374813
   15 Atom          -978.570506        -977.084740        -975.949028
   16 Atom          -979.637026        -977.780090        -977.086929
   17 Atom          -394.239541        -393.655029        -393.537631
   18 Atom          -394.413199        -393.689689        -393.595758
   19 Atom            -1.922350          -1.432433          -1.419193
   20 Atom            -1.921021          -1.419914          -1.407088
   21 Atom            -1.913570          -1.425796          -1.400256
   22 Atom            -1.917816          -1.425322          -1.405310
 -------------------------------------------------------------------

   I would like to know why, and how can I compute a real value for the
field gradient for each atom ?

   Thanks JYK

e-mail: [email-masked]
        Jean-Yves Kempf
        Universite de Nancy I
        Laboratoire de chimie theorique
        BP 239
        54506 Vandoeuvre-les-Nancy France.