Second-Order CI Possible?

The Matt thompsma at
Mon Oct 28 22:22:12 GMT 2002

I just started using Molpro and am trying to duplicate some calculations
I did in GAMESS to get to know Molpro.  In GAMESS, I had done some SOCI
(=second-order CI) calculations.  These are a CASSCF in an active space
(for me up to 8 CSFs with I2-, one valence hole) and then a CISD to an
external space of 16 orbitals from the original CASSCF CSFs.  In the end
these took about a 3 hours to complete (a six-state SOCI).

What I am wondering is if this type of calculation is possible in
Molpro.  I naively tried a CASSCF of this 26 orbital space but that, of
course, caused a "need more memory" error the likes of which I'd never

Is it possible, or is Molpro just not setup to handle this type of

Thank you for any help,
Matt Thompson
"And isn't sanity really just a one-trick pony, anyway?  I mean,
all you get is one trick, rational thinking, but when you're good
and crazy, ooh ooh ooh, the sky's the limit!" -- The Tick
  The Matt --
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