RASSI complaining with LU partitioning

Posted by Vérot on March 20, 2015 at 09:29:33:

I'm doing some calculations for nickelocene and I am computing the zero field splitting with the 45 states generated by the d8 in the 3d orbitals.

With a CAS(8,10) and at the CASSCF or CASPT2 level, everything works fine but when I enlarge the CAS space to a CAS (16,9) I have teh following message from RASSI :
Nr of states: 25

State: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
JobIph: 1 2 2 2 3 3 3 4 4 4 5 5 5 5 5 5 6 6 6 7
Root nr: 1 1 2 3 1 2 3 1 2 3 1 2 3 4 5 6 1 2 3 1

State: 21 22 23 24 25
JobIph: 7 7 8 8 8
Root nr: 2 3 1 2 3

RASSI CANNOT CONTINUE. THE PROBLEM AT HAND
IS PROBABLY NOT SOLUBLE. THE TWO ORBITAL
SPACES ARE TOO DISSIMILAR.
LU PARTITIONING IS TROUBLESOME. DIAGONAL
ELEMENT NR. 13 IS TOO SMALL:
IN MATRIX CXA IT IS 1.00000000000000
IN MATRIX CYB IT IS 1.596537582592096E-004
EVEN AFTER OPTIMAL PIVOT-TRANSFORMATION.

I checked my orbitals, it seems ok (the d orbitals are in the CAS) but I don't know how to solve this problem. It points to the element 13, is it because it is my thirteenth state (among the 25) which is causing trouble ?

If anyone has any hint on how to solve this problem, I would be truly grateful.

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Re: RASSI complaining with LU partitioning Vérot 12:18:15 3/20/15 (0)
Re: RASSI complaining with LU partitioning Vérot 09:37:12 3/20/15 (1)
- Re: RASSI complaining with LU partitioning Steven Vancoillie 08:59:20 3/26/15 (0)

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Comments:
: I'm doing some calculations for nickelocene and I am computing the zero field splitting with the 45 states generated by the d8 in the 3d orbitals. : With a CAS(8,10) and at the CASSCF or CASPT2 level, everything works fine but when I enlarge the CAS space to a CAS (16,9) I have teh following message from RASSI : : Nr of states: 25 : State: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 : JobIph: 1 2 2 2 3 3 3 4 4 4 5 5 5 5 5 5 6 6 6 7 : Root nr: 1 1 2 3 1 2 3 1 2 3 1 2 3 4 5 6 1 2 3 1 : State: 21 22 23 24 25 : JobIph: 7 7 8 8 8 : Root nr: 2 3 1 2 3 : RASSI CANNOT CONTINUE. THE PROBLEM AT HAND : IS PROBABLY NOT SOLUBLE. THE TWO ORBITAL : SPACES ARE TOO DISSIMILAR. : LU PARTITIONING IS TROUBLESOME. DIAGONAL : ELEMENT NR. 13 IS TOO SMALL: : IN MATRIX CXA IT IS 1.00000000000000 : IN MATRIX CYB IT IS 1.596537582592096E-004 : EVEN AFTER OPTIMAL PIVOT-TRANSFORMATION. : : I checked my orbitals, it seems ok (the d orbitals are in the CAS) but I don't know how to solve this problem. It points to the element 13, is it because it is my thirteenth state (among the 25) which is causing trouble ? : If anyone has any hint on how to solve this problem, I would be truly grateful.

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