[molpro-user] FCI iteration termination: expansion set singular

[Steven Fiedler]

Dear Molpro users:

I am conducting a series of FCI calculations of multiple states of the 
He2* dimer at various internuclear separation distances with a large 
basis set.  Calculations of small separation distances (< 2 bohr) 
terminate after a number of FCI iterations with the following error: 
"expansion set singular".  Prior to this error, the lowest root appears 
to be converging rapidly to minus infinity.

Insight or advisement would be appreciated.

Steven Fiedler

-- 
Department of Chemistry and Biochemistry
California State University, Northridge