[gpaw-users] singlet-triplet transition in GPAW tddft

[Jens Jørgen Mortensen]

On 02/03/2017 10:57 AM, Michael Walter via gpaw-users wrote:
> Dear Ivano,
>
> 2017-02-03 10:30 GMT+01:00 Ivano E. Castelli <ivano at chem.ku.dk 
> <mailto:ivano at chem.ku.dk>>:
>
>     Dear Dr. Michael Walter.
>
>     My name is Ivano Castelli, I am a post doc in Jan Rossmeisl group
>     at Copenhagen University.
>     I am currently working on calculating spin singlet-triplet
>     transitions in radicals like carboxylic acids using GPAW.
>     I have found a paper of yours where you used the TDDFT module
>     implemented in GPAW to calculate these singlet-triplet transitions
>     (http://dx.doi.org/10.1063/1.2943138
>     <http://dx.doi.org/10.1063/1.2943138>).
>     I have followed the instructions here:
>     https://wiki.fysik.dtu.dk/gpaw/exercises/lrtddft/lrtddft.html
>     <https://wiki.fysik.dtu.dk/gpaw/exercises/lrtddft/lrtddft.html>
>     but in the output of the calculation I cannot see when the
>     transition is singlet-triplet for example when I calculate the
>     excitation energies for CO as shown here:
>     http://www.psi-k.org/newsletters/News_98/Highlight_98.pdf
>     <http://www.psi-k.org/newsletters/News_98/Highlight_98.pdf>
>     I was wondering if you can help on this matter.
>
>
> The simplest approach is:
>
> 1. to calculate CO spin paired, this will give you the singlets only.
> 2. Then you force spin (spinpol=True in the ground state calculation) 
> and you'll get both singlets and triplets. So, the triplets are the 
> ones missing in 1.
>
> There are also other possibilities starting from 2:
>
> 3. The LrTDDFT object has a function "singlets_triplets" that should 
> give you both separated. I think it works and is tested, but better 
> check against 1+2 above.
> 4. Use the vanishing oscillator strength as a hint for triplets and 
> use LrTDDFT.analyse() for the Kohn-Sham contributions.
>
> I'm painfully aware that the documentation could be improved to 
> explain these things and would be very happy, if you could help on 
> this matter.

Here is a description of how to work on the documentation (it works the 
same way for both ASE and GPAW):

https://wiki.fysik.dtu.dk/ase/development/writing_documentation_ase.html

Jens Jørgen

>
> Best,
> Michael
>
>
>     Thank you in advance,
>     best regards,
>     Ivano
>
>     -- 
>     Ivano E. Castelli
>     Postdoc
>
>     Department of Chemistry
>     University of Copenhagen
>     Universitetsparken 5
>     Building D, room S04
>     DK-2100 Copenhagen Ø
>     ivano at chem.ku.dk <mailto:ivano at chem.ku.dk>
>     +45 53538491 <tel:%2B45%2053538491>
>
>
>
>
> -- 
> ------------------------------------------
> PD Dr Michael Walter
> Addresses:
> - Fraunhofer IWM, Wöhlerstrasse 11, D-79108 Freiburg i. Br., Germany
>   Tel.: +49 761 5142 296
> - FIT Freiburg Centre for Interactive Materials and Bioinspired 
> Technologies, Georges-Köhler-Allee 105, 79110 Freiburg, Germany
>   Tel: +49 761 203 95072
> email: Michael.Walter at fmf.uni-freiburg.de 
> <mailto:Michael.Walter at fmf.uni-freiburg.de>
> www: 
> http://www.functional-nanosystems.uni-freiburg.de/People/PDWalter/group
> publications: http://scholar.google.com/citations?user=vlmryKEAAAAJ&hl=en
>
>
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