Author Topic: Mulliken Populations and Orbital Contributions  (Read 2469 times)

Dempsey

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Mulliken Populations and Orbital Contributions
« on: May 15, 2023, 06:21:41 PM »
Dear Users,

I am new to population analyses so please correct any misunderstanding. Is there a way to see which MOs contain individual electrons? For example, if I have a Pu(IV) atom contributing 4 spin-up 5f electrons to my system, can I see which MO is occupied by these electrons?

I did the Mulliken analysis on my converged system (PBE0/def2-TZVP) and am unsure about the populations. The MOs with major Pu f populations are the LUMO, LUMO+1, and LUMO+2 with over 89% in each case. Of course, it's not too surprising to find actinide f contributions to higher energy, unoccupied orbitals. But still, there are 4 actinide 5f electrons in my system somewhere, can I know which MO they are in?

On another note, is there a way to tell if the actinide d contributions are 6d specifically for example?

Best,
Dempsey


uwe

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Re: Mulliken Populations and Orbital Contributions
« Reply #1 on: May 16, 2023, 05:13:41 PM »
Hi,

if I got you right, you want to know which atomic orbitals are part of which occupied molecular orbital?
What might help is to run

tm2molden mostat

and hit a few times <Enter> to accept all defaults.

This will create a new file named mostat.out which contains a list of all molecular orbitals, and for each molecular orbital it will tell you:
- The number of the molecular orbital (same number as eiger prints)
- the symmetry
- the orbital energy (in atomic units and in eV)
- the spin
- the occupation (so how many electrons do occupy this molecular orbital)
- a list of the most important atomic orbitals with
   - which atom they stem from
   - which quantum number
   - how much they contribute to the orbital (in %)

Here's an example:

Code: [Select]
MO Index (from eiger):      47
 Sym=    24a
 Energy [Hartree]= -.38105175112758E+00
 Energy [eV]= -.10368946293530E+02
 Spin= Alpha
 Occup= 1.000000
contribution of AO   3 pu    1 fy2z     is:   22.509 %
contribution of AO   3 pu    1 fx2z     is:   22.345 %
contribution of AO   3 pu    2 fy2z     is:   16.127 %
contribution of AO   3 pu    2 fx2z     is:   15.995 %
contribution of AO   3 pu    3 fy2z     is:    9.595 %
contribution of AO   3 pu    3 fx2z     is:    9.497 %
contribution of AO   3 pu    4 fy2z     is:    1.942 %
contribution of AO   3 pu    4 fx2z     is:    1.925 %
contribution of AO   1 o     1 dy2      is:    0.015 %

 MO Index (from eiger):      48
 Sym=    25a
 Energy [Hartree]= -.37276114442998E+00
 Energy [eV]= -.10143347394341E+02
 Spin= Alpha
 Occup= 1.000000
contribution of AO   3 pu    1 fx2y     is:   41.313 %
contribution of AO   3 pu    2 fx2y     is:   29.178 %
contribution of AO   3 pu    3 fx2y     is:   16.795 %
contribution of AO   3 pu    1 fy3      is:    4.266 %
contribution of AO   3 pu    2 fy3      is:    3.013 %
contribution of AO   3 pu    4 fx2y     is:    2.886 %
contribution of AO   3 pu    3 fy3      is:    1.746 %
contribution of AO   3 pu    4 fy3      is:    0.304 %

etc.

Please note that this does not work for two-component (keyword $soghf) jobs.


Dempsey

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Re: Mulliken Populations and Orbital Contributions
« Reply #2 on: May 31, 2023, 12:33:41 PM »
Hi,

This is exactly what I wanted thank you!

One further question, in my case I have Pu(IV) which has an f4 occupation, in my mostat.out file should I be able to find MO's where the Pu f-orbitals contribute and are occupied or is it possible that the MO's with Pu f contribution are all unoccupied? I do see some occupied MOs with very minor f contributions but it is the LUMO that is related to the f, in your opinion is this normal?

Also, you say that mostat lists the quantum number. In this case, are 1 fx2y and 2 fx2y the 4f and 5f. Sorry for any misunderstanding, I'm unsure what 1f could mean.

Best,
Dempsey