MRCI thresholds or contractions

[Fabio Mariotti]

	Dear Molpro users,

	I have the following problem:
	I'm running an ACPF calculation on HF molecule
	close to dissociation:
	namely i'm computing 4 points. Here the distancies
	and ACPF energies:

   VRDFH        EACPF
    4.95   -100.0478137
    5.00   -100.0478125
    5.05   -100.0477949
    5.10   -100.0477939

	as you can see from 5.00 to 5.05 there is a "jump"

	After a while I realised that the main difference
	in the two points (5.00/5.05) is the number of
	contractions in the MRCI/ACPF part.

	So for the 5.00 geometry I have:

 Total number of contracted configurations:         2588
 Total number of uncontracted configurations:       8642

	While for 5.05 geometry:

 Total number of contracted configurations:         2368
 Total number of uncontracted configurations:       8642


	For reference here is my current test input:
===========================================================
***,nh3                     !A title
!
print,ref,pspace;
gprint,basis,orbitals=8;
!
rdfh=1.00000000;
geometry={angstrom;
F;
H, 1, rdfh;
}
!
gthresh,oneint=1.0E-14,twoint=1.0E-14,zero=1.0E-14,preface=1.0E-20;
!
basis=aug-cc-pVDZ;
!
i=0;
do ist=4.90,5.1,0.05;
!
i=i+1;
rdfh=ist;
vrdfh(i)=rdfh;
!
hf;accu,20;core;
!
casscf;
acpf;
eacpf(i)=energy;
!
enddo;
!
text,START TABLE FOR get_molpro_table.pl;
table,vrdfh,eacpf;
plot,FILE=plot.dat;
text,END TABLE FOR get_molpro_table.pl;
!
---
!
===========================================================


I've been playing around with all the cutoff/thresholds I know
about but with no results!

Does anybody knows how I can solve this problem?

The CAS before the MRCI looks identical (beside the small
changes due to the different geometries).

Which other parameters the number of contractions can
depend on?

(I'm using molpro 2002.3 and 2002.6)

	Thanks in advance
	Fabio


-- 
=============================================
Dr Fabio Mariotti - Tel.: +49 (0)208 306 2157
Max Planck Institute - Kaiser-Wilhelm-Platz 1
Muelheim an der Ruhr, 45470 Germany