[Molpro-user] Calculation of Potential

[Benjamin Bulheller]

Hi!

I need to calculate the electrostatic potential of a compound at  
several thousand points around the molecule. This has been done before  
(with Molpro 2002.6) using the following code:

    property
    density,2100.2
    pot,,-12.28322, -2.83459, -0.94486
    pot,,-12.24522, -0.94486,  1.88973
    pot,,-12.67322,  1.88973,  0.94486
    pot,,-11.33836, -2.83459, -3.77945
    pot,,-10.12736,  2.83459,  2.83459
    etc...

In 2002.6 this worked with up to 2500 "pot" statements while in 2006.1  
only 30 points are possible and I get a "Too many operators" error  
with more than that. This happens in propa.f caused by the MXOPER  
variable.

Using a slightly crude workaround I can wrap the pot statement in  
nested do loops and for some reason Molpro will then compute 148  
points and fail thereafter.

Am I doing something wrong there in general? What puzzles me is that  
it obviously must have worked in 2002.6 but stopped working in 2006.1  
(without changes in the concerned code section), is there any  
explanation for that?

Thank you very much in advance,

Ben



=================================================
Example Input for H2
=================================================

print,basis
gprint,orbitals
geomtyp=xyz

geometry={
nosym
2
Title
H 0.0 0.0 0.0
H 0.0 0.0 1.0
}

basis={
  ! HYDROGEN   [7s,3p] -> (2s,1p)  ANO-S
  s,H , 
82.636374,12.409558,2.8238540,0.79767000,0.25805300,0.08989100,0.03146200
  c,1.7, 0.0025641, 0.0192126, 0.0950512, 0.3018678, 0.4874459,  
0.23547943, 0.01577776
  c,1.7,-0.0046008,-0.0324447,-0.1710737,-0.5048672,-0.0948920,  
0.37085551, 0.65565134
  p,H ,1.6625000,0.41560000,0.10390000
  c,1.3, 0.3012771, 0.6800574, 0.1985627
}

int;
hf;
property
density,2100.2
dm,,0.0,0.0,0.0;

property
density,2100.2
pot,,-12.28322, -2.83459, -0.94486
pot,,-12.24522, -0.94486,  1.88973
pot,,-12.67322,  1.88973,  0.94486
pot,,-11.33836, -2.83459, -3.77945
pot,,-10.12736,  2.83459,  2.83459
pot,, -9.33836,  2.83459,  3.77945
pot,, -8.25736,  3.77945,  1.88973
! plus 1000 and more additional lines for other points


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