Lowdin population analysis

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Hi,
  According to the manual, constrained DFT uses Lowdin populations by default (Mulliken not recommended). I would like to set up a calculation by taking converged MOs as a guess, then running CDFT with a cluster of atomic charges constrained to the value in the original calculation (just as a check, to ensure the same or similar wavefunction is produced). To do this, I guess I'd need the Lowdin charges for the original WF. Is there a database key/value pair that can be set to produce Lowdin population analysis, and if so what is it?

Thanks.

  • Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Chris,

How counter intuitive it may sound, but adding the keyword "mulliken" to the dft block should print out both the Mulliken and Lowdin charges.

Bert


Quote:Cchang Oct 7th 10:32 pm
Hi,
  According to the manual, constrained DFT uses Lowdin populations by default (Mulliken not recommended). I would like to set up a calculation by taking converged MOs as a guess, then running CDFT with a cluster of atomic charges constrained to the value in the original calculation (just as a check, to ensure the same or similar wavefunction is produced). To do this, I guess I'd need the Lowdin charges for the original WF. Is there a database key/value pair that can be set to produce Lowdin population analysis, and if so what is it?

Thanks.

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Thanks Bert!
  Cheers,  Chris

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Not seeing Lowdin charges
Bert,

I tried adding "mulliken" in both a separate properties section, and in the dft block as you suggested; however, I'm not seeing anything labeled as "Lowdin" or anything else that would suggest an alternative charge model. What should I be looking for? NWChem 6.0 on Hopper @ NERSC.

Thanks,

Chris

  • Niri Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Hi Chris,

Try the following:

dft
 mulliken
...
end
task dft

this will print out Mulliken and Lowdin sections in the output. Let me know if it doesn't work.

Best,
-Niri

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Hi Niri,
What keyword would be good to search on to find the Lowdin section? With the MO output, the log files are quite long.

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Niri--Never mind, the analysis output contained the Lowdin data this time, and the log file was much shorter than it has been. Curious.

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Quote:Cchang Jan 4th 9:55 am
Niri--Never mind, the analysis output contained the Lowdin data this time, and the log file was much shorter than it has been. Curious.


Dear NWCHEM users,
I did the Lowdin and Mulliken population analysis to get partial charges for QM atoms in a QMMM simulation. But, results seems strange to me because, for example, for an O atom it results in 8.43 while the ESP analysis results in -0.64 (that looks reasonable). Is there any one who can help me to extract the real partial charges out of these numbers?

Best,
Hassan.

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Quote:Niri Dec 27th 4:21 pm
Hi Chris,

Try the following:

dft
 mulliken
...
end
task dft

this will print out Mulliken and Lowdin sections in the output. Let me know if it doesn't work.

Best,
-Niri


Thanks for the post. I did this along with / separately

dft
cdft 1 x charge 0.0 pop lowdin
....
end
task dft

but had no luck in getting the Lowdin charges with NWCHEM 6.1 @ hopper.nersc

Can some one please enlighten me with the proper keyword? Thanks in advance.
Edited On 7:58:36 PM PDT - Sun, Oct 14th 2012 by Himadride

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Himadride,
The input below is an example for how to calculate the Lowdin population analysis.

start n4
geometry
N -0.08327803 -0.57614137 -0.00048040
N 0.17646529 -1.65378010 0.00040716
N 0.44621621 1.56364198 0.00224466
N -0.53940347 0.66627949 -0.00217143
end
basis
* library 6-31g*
end
dft
odft
xc b3lyp
mult 3
cdft 1 2 charge 1.0
cdft 3 4 charge -1.0
mulliken
end

task dft

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Thanks for the reply. But it still does not work. Is there any other work around ? Thanks in advance.
Edited On 12:24:18 PM PDT - Mon, Oct 15th 2012 by Himadride

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I have just tried it with both the 6.1 and 6.1.1 default binaries on hopper and it works for me.

apra/cdft> egrep wdin cdft.out.2325240.sdb
    Total Density - Lowdin Population Analysis
Spin Density - Lowdin Population Analysis

Quote:Himadride Oct 15th 12:16 pm
Thanks for the reply. But it still does not work. Is there any other work around ? Thanks in advance.

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Thank you for the reply. It definitely works with the closed shell systems. My system is open shell and I use RODFT module accompanied by cgmin solver. Can you please let me know about it, whether with RODFT open shell systems too similar keywords are valid? Thanks in advance.

  • Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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This is a feature that has not been implemented in the RODFT yet. This will be made available in our next release.

Bert

Quote:Himadride Oct 18th 7:11 am
Thank you for the reply. It definitely works with the closed shell systems. My system is open shell and I use RODFT module accompanied by cgmin solver. Can you please let me know about it, whether with RODFT open shell systems too similar keywords are valid? Thanks in advance.


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