[CP2K-user] SMEAR vs. LSD+RELAX_MULTIPLICITY/MULTIPLICITY

[Ivan Gladich]

Dear CP2K users,

 

I would like some clarifications about SMEAR vs. LSD +RELAX_MULTIPLICTY in 
cp2k. I am trying to simulate a metallic nanoparticle (few tens of atoms) 
in water

 

I have two (maybe simple) questions:

 

a) From this post 

https://groups.google.com/forum/#!topic/cp2k/GEKLwRQat_M

 

my understanding is that the SMEAR option populates the alpha and beta 
channel according to a Fermi-Dirac 

 

In LSD + MULTIPLICITY (or LSD + RELAX MULTIPLICITY)

https://groups.google.com/forum/#!searchin/cp2k/smearing$20spin%7Csort:date/cp2k/ugkJLz4PSSI/C-ProBR6BwAJ

 

my understating is that after energy levels are calculated, electrons are 
placed according to Aufbau principle, from the lowest to the highest in an 
unrestricted scheme. If MULTIPLICITY is set, the multiplicity is fixed, 
with RELAX_MULTIPLICITY no

 

Please correct me if my understanding is mistaken.

 

Question: are the two approaches (SMEAR vs. LSD +RELAX_MULTIPLICTY) 
equivalent? One approach is more appropriate than the other for particular 
systems? Is the computational cost the same?

 

b) If I use LSD +MULTIPLICTY in the output I get the

 

“Integrated absolute spin density” and  “Ideal and single determinant S**2”

 

That are equations (2.271) and (2.272) in “Modern Quantum Chemistry: 
Introduction to Advanced Electronic Structure Theory,Attila Bangha Szabo, 
Neil S. Ostlund “

 

https://groups.google.com/forum/#!topic/cp2k/flEEaseAd7c

 

 

If I see the output of my calculation with SMEAR I do not see such or any 
other information about the spin state of my system. 

 

Question: Is this expected? How I can easily get information about the spin 
state of my system when using SMEAR?

 

Thank you very much for any possible help

 

Best regards

Ivan
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