Subject: SCF problem with G98 on T90

From: [email-masked] (Heather Carlson)
Date: Wed, 21 Apr 1999 16:40:17 -0700 (PDT)

Hello All,

My students and I have a problem with the newly installed G98 on
the T90 at the SDSC.  In short, G94 gave us and energy of -397.85 H
for our system, but G98 gives us -1E+145!!!  (Yes, same input...
and not an isolated incident/structure.)  Does anyone know what is
going on (full account below)???

Thank you, Heather
___________________________________________________________________
                   Dr. Heather A. Carlson, Ph.D.
            American Cancer Society Postdoctoral Fellow
         La Jolla Interfaces in Science Postdoctoral Fellow

UCSD, Dept. of Chemistry and Biochemistry     Phone: (619) 822-1469
9500 Gilman Drive, 4202 Urey Hall               Fax: (619) 534-7042
La Jolla, CA 92093-0365         E-mail: [email-masked]
___________________________________________________________________

> System: Alanine and one water molecule
>
> We tried to finish some IRCs that we had started with G94, and
> they would not run.  So we back-tracked the project to re-
> calculating the TSs (we have 4).  One ran properly, the other 3
> all fell victim to the same error...  supposedly, our gradients
> are out of range.
>
> Our command lines are:
> #N 6-31+G* OPT=(TS,CalcAll,NoRaman) SCF=DIRECT
>
> Charge is zero; multiplicity is one.  The code reads in the Zmat
> input just fine, providing proper input and standard orientation
> cartisian coordinates that perfectly match the structure in the
> Zmat input:
>
>                      Standard orientation:
> ----------------------------------------------------------------
> Center     Atomic   Atomic           Coordinates (Angstroms)
> Number     Number    Type           X           Y           Z
> ----------------------------------------------------------------
>    1          7        0       -0.383566   -1.364896    0.499169
>    2          6        0        0.550279   -0.546147   -0.342259
>    3          6        0        0.384693    0.957734    0.006937
>    4          8        0        1.380278    1.605834    0.160026
>    5          8        0       -0.814323    1.389658    0.087560
>    6          1        0        0.199639   -0.681904   -1.358544
>    7          6        0        1.977132   -1.045635   -0.196762
>    8          1        0        2.632312   -0.468463   -0.832898
>    9          1        0        2.332086   -0.932044    0.821286
>   10          1        0        2.049184   -2.091742   -0.483460
>   11          1        0       -1.676934    0.680044   -0.141141
>   12          1        0       -0.273038   -2.345158    0.301267
>   13          1        0       -0.202638   -1.231763    1.480958
>   14          8        0       -2.454641   -0.289740   -0.302798
>   15          1        0       -1.431265   -1.055390    0.264615
>   16          1        0       -3.307509   -0.161041    0.087933
> ----------------------------------------------------------------
> This is an exact match of the final output structure from the
> original TS optimization with G94; rotational constants also
> match.
>
> Though the structures are the same, the N-repulsion energies are
> not: G94 gives 341.8720848317 H but G98 gives 341.8720849191 H.
> Now for the interesting part...
>
> G94 gives the following SCF results
>    SCF Done:  E(RHF) =  -397.853912102     A.U. after 12 cycles
>               Convg  =    0.4285E-08             -V/T =  2.0021
>               S**2   =   0.0000
> G98 gives
>    SCF Done:  E(RHF) = -0.104107509526+146 A.U. after  2 cycles
>               Convg  =    0.2575E-12             -V/T = *******
>               S**2   =   0.0000
>
> Needless to say, all hell breaks loose at this point with out-
> rageous eigenvalues and the following partial charges:
>            Total atomic charges:
>                         1
>             1  N   -4.978340
>             2  C    0.639611
>             3  C    4.910643
>             4  O    6.155526
>             5  O    4.662892
>             6  H    0.136323
>             7  C   -5.996997
>             8  H   -0.166654
>             9  H    0.998955
>            10  H   -0.078574
>            11  H   -0.993813
>            12  H   -0.590006
>            13  H    0.908727
>            14  O   -3.981953
>            15  H   -0.625232
>            16  H   -1.001110
>            Sum of Mulliken charges=   0.00000
>