core ionization energy

Luca luca.d... at
Tue Nov 28 10:11:09 UTC 2017

Dear Developers


I am trying to calculate the O 1s core ionization energy of H2O. My idea is 
to evaluate the difference between

the energy of H2O in its ground state and the energy of an H2O+ with a hole 
in the O1s state.

My problem is that when running a Delta–SCF, cp2k always excite the alpha 

Thus, before doing the Delta-SCF, one should get the right initial 
configuration for H2O+ by making a spin flip of the electron in the HOMO of 
the H2O+.

I tried with the MOM method by adding the keyword:


         DEOCC_ALPHA 5

         OCC_BETA 5

      &END MOM

But cp2k complains writing:

      ‘Incorrect multiplicity of the MOM reference electronic state ‘ 

… although I put in my input both LSD and MULTIPLICITY 2.


Then I gave a chance to the WFN_MIX by adding the lines:



           RESULT_MO_INDEX 1


           RESULT_SCALE 0.0


           ORIG_MO_INDEX 1


           ORIG_SCALE 1.00





However, in this case, I get a segmentation fault.

Could you please point out me where I am doing wrong?


All the best.

Luca S.
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