molpro2002.6 ECP bug?

[Jacek Klos]

Dear Molpro Users,

I hit such a problem when using effective core potential for
Xe atom in interaction with NO molecule. In molpro 2002.3 and
molpro 2000.1 input I use works and gives RCCSD(T) energy of the 
Xe-NO molecule. But when the same input is used in molpro 2002.6
I get different solution of RHF program and RCCSD is exiting with
UNREASONABLE NORM error. The CCSD exits because of something wrong 
is going in RHF I presume. Here is the input:

***,Xe-NO 
memory,15,m
gthresh,energy=1.d-9;
gprint,basis;
geometry={noorient;
q1;
q2,q1,1.0
N,q1,rnx,q2,90.0;
O,q1,rox,q2,90.0,N,180.0;
Xe,q1,r,q2,beta,N,0.0
Be,q1,rbe,q2,beta,N,0.0;
          }
rox=0.5371799322 ang
rnx=0.6135900677 ang
theta=0.0
beta=90.0-theta
basis={
ecp,Xe,ECP46MWB;
spdf,Xe,ECP46MWB;
spdf,n,avtz;c;
spdf,o,avtz;c;
sp,be,0.9,0.3,0.1;
df,be,0.6,0.2;
g,be,0.3;}
r=20.0 ang
rbe=r*0.5 ang
text,calculation for complex BIS ;
dummy,be
rhf;wf,23,2,1;maxit,90
orbprint,0
rccsd(t);maxit,90;
---

In Molpro 2002.3 RHF energy is:-144.56731345
but in 2002.6 version RHF is:-143.91398149


First iterations in RHF in 2002.3 and 2002.6 versions:

RHF iterations from Molpro 2002.6:


 ITERATION    DDIFF          GRAD             ENERGY        2-EL.EN.            
DIPOLE MOMENTS         DIIS
    1       .000D+00       .000D+00       -70.56488111    444.580663    
.000000 301.451947    .000000    0
    2       .000D+00       .221D+00       -73.15131316    170.093612    
.000000 **********    .000000    0
    3       .628D+00       .803D-01       -87.90178385    402.689735    
.000000 301.531151    .000000    1
    4       .364D+00       .179D+00       -73.02868137    169.716549    
.000000 **********    .000000    1
    5       .365D+00       .934D-01      -102.53801608    355.594529    
.000000 301.571132    .000000    2
    6       .245D+00       .125D+00      -111.74460806    317.557998    
.000000 302.670775    .000000    3
    7       .901D-01       .884D-01      -134.11525158    234.103093    
.000000 189.863457    .000000    4
    8       .928D-01       .400D-01      -139.43368935    146.100659    
.000000 **********    .000000    5
    9       .692D-01       .222D-01      -142.37680048    200.240607    
.000000  74.352007    .000000    6
   10       .516D-01       .199D-01      -142.61964648    196.806101    
.000000  74.632483    .000000    7

RHF iterations from Molpro 2002.3:

 ITERATION    DDIFF          GRAD             ENERGY      2-EL.EN.           
DIPOLE MOMENTS          DIIS
    1       .000D+00       .000D+00       -70.56488111  444.580663   
.000000 301.451947    .000000     0
    2       .000D+00       .221D+00       -75.05389406  167.962428   
.000000 **********    .000000     0
    3       .627D+00       .849D-01       -87.90178428  402.689735   
.000000 301.531150    .000000     1
    4       .364D+00       .179D+00       -77.68623161  161.516536   
.000000 **********    .000000     1
    5       .581D+00       .924D-01      -102.27524477  356.553891   
.000000 301.551912    .000000     2
    6       .515D+00       .126D+00      -112.19090149  317.041387   
.000000 303.057258    .000000     3
    7       .110D+00       .866D-01      -139.77210755  219.054895   
.000000 112.749107    .000000     4
    8       .104D+00       .322D-01      -144.47518819  169.737969   
.000000    .217617    .000000     5
    9       .452D-01       .816D-02      -144.52805483  170.443554   
.000000   -.231275    .000000     6
   10       .803D-02       .508D-02      -144.54885496  171.414992   
.000000    .079383    .000000     7

First iteration is the same, third very similar, but then it starts to 
deviate and final solution is different. 
I checked in case of Kr, which interest me more, there is no problem
when I choose  aug-cc-pv*z basis, but when I choose ECP potential for Kr
the Molpro 2002.6 exits with similar error like in case of Xe atom.

I checked if it can be the reason of bond-functions. No, this behavior 
repeats without bond functions as well. I checked if it happens only for 
Xe atom. No, Xe atom alone finishes in the same way in both revisions of
Molpro using ECP potential. 

Why the same input for Xe-NO dimer behaves differently in these 2 
revisions of Molpro 2002?

Platform used: IBM AIX 5.1

Anybody with similar problem before?

Best regards
-- 
Jacek A. Klos
---------------------------------
Quantum Chemistry Laboratory     |
Department of Chemistry          |
University of Warsaw             |
Pasteura 1 Street                |
02-093 Warsaw                    |
Poland                           |
(+4822)8220211 ext. 213          |
e-mail: jakl at tiger.chem.uw.edu.pl|
---------------------------------