Molcas Forum

Rafael

Member

Registered: 2016-11-16

Posts: 12

Double core-excitation

Hi,
I was wondering if it is possible to get a double core excited state using RASSCF.
I swap the core orbital with a valence one, in order to keep the 1s orbital in RAS3, so I can set the maximum number of electrons in the 1s orbital. Here is the RASSCF part of my input:

 &RASSCF &END
LUMORB
Symmetry
 1
Spin
 1
SUPSYM
 1
 1 1
ALTER
 1
 1 1 11
nActEl
 14 0 0
Inactive
 0
Ras1
 0
Ras2
 10
Ras3
 1
CIRO
 4 4 1
End of input

But when I use this, I get and error memory.

Is it possible to get this type of state? A double core-excited one?

Best Regards,
Rafael

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Double core-excitation

What's the error? Is 0 inactive orbitals correct? You are also setting the maximum number of electrons in Ras3 to 0, it would be easier to remove Ras3.

Rafael

Member

Registered: 2016-11-16

Posts: 12

Re: Double core-excitation

Hi Ignacio,

Thank you for the reply.

The RASSCF just stops with the error:

                          RASSCF iterations: Energy and convergence statistics
                          ----------------------------------------------------

      Iter CI   SX   CI       RASSCF       Energy    max ROT     max BLB   max BLB  Level Ln srch  Step   QN   CPU Time
          iter iter root      energy       change     param      element    value   shift minimum  type update hh:mm:ss
--- Stop Module:  rasscf at Fri Nov 11 16:20:38 2016 /rc=                   -1 (Unknown) ---
--- Module rasscf spent 6 minutes and 28 seconds
 Aborting..

About this inactive space, it is correct to be empty, because I'm using CO as example, which is rather small system, so all orbitals and electrons are in the active space.

In RAS3 I chose 0 electrons because that is the idea of the calculation I'm trying. The O1s orbital is placed in RAS3 and then I do a double core-excitation. So the final state is the O1s orbital empty (no electron on it).

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Double core-excitation

But if the maximum number of electrons in RAS3 is going to be 0, you'd achieve the same thing setting RAS3=0, have you tried it? Does it work with single excitations (NActEl = 14 0 1)? Should SupSym refer to orbital 1 or orbital 11 (I presume orbital 11 is the core orbital after applying the Alter keyword)? Have you tried without CIRoot?

Rafael

Member

Registered: 2016-11-16

Posts: 12

Re: Double core-excitation

The calculation works fine for single core-excitation using NActEl = 14 0 1. SupSym refer to orbital 1, to avoid the core-orbital to return to the original position, remaining in RAS3.

But if I set RAS3=0, how could I compute a double core-excitation?

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: Double core-excitation

By putting your core orbital initially in the virtual space (Alter) and preventing its rotation with the other orbitals (SupSym), you effectively have double core excitations, don't you? Calling the core orbital secondary (virtual), or RAS3 with a maximum of 0 electrons makes no difference in principle, but while I know for sure the program is supposed to work with virtual orbitals, I'm not 100% sure it does with non-0 RAS3 and 0 maximum electrons.

To be sure about SupSym and Alter, I'd take the resulting orbitals from the single core excitations (which you say is correct) as input orbitals, then you don't need Alter and you apply SupSym to orbital 11 (the core).