<div dir="ltr">Dear Maria,<div><br></div><div>very happy to hear that you are using sTDA!</div><div><br></div><div>MATAGA_NISHIMOTO_CEXP and MATAGA_NISHIMOTO_XEXP were added to enable more flexibility in the parameter choice, with CEXP referring to the parameter dubbed alpha in Eq. 28 in Ref. <a href="https://pubs.acs.org/doi/full/10.1021/acs.jctc.2c00144">https://pubs.acs.org/doi/full/10.1021/acs.jctc.2c00144</a>, identical with the parameter alpha of the original Grimme paper, parameterizing Coulomb contributions.</div><div>MATAGA_NISHIMOTO_XEXP analogously refers to parameter beta in Eq. 29 of the reference above, also dubbed beta in the original Grimme paper, parameterizing Exchange contributions.</div><div>FRACTION is referring to a_EX in Eq. 29, thus resembling the coupling parameter to define the amount of exact exchange as it is in hybrid functionals.</div><div>DO_EXCHANGE enables to switch off exchange contributions completely.</div><div><br></div><div>Depending on the chosen ground-state reference, it is important to adjust not only the amount of exact exchange, but also CEXP and XEXP. In the sTDA manual of Grimme and also in corresponding papers, several values for alpha and beta are suggested depending on the GS functional, differing significantly from the standard choice alpha = 1.42 + a_EX *0.48 and beta = 0.2 + a_EX*1.83. However, parameterization was based on molecular test sets and depending on your systems, it might be beneficial to reoptimize these parameters.</div><div><br></div><div>Hope this helps, also happy to discuss further questions.</div><div>Best regards,</div><div><br></div><div>Anna</div><div><br></div><div><br></div><div><br></div><div><br></div><div> <br></div><div> </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Am Di., 13. Dez. 2022 um 10:58 Uhr schrieb Maria Fumanal <<a href="mailto:mfumanal@gmail.com">mfumanal@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">Dear CP2K users/developers,<div><br></div><div>I have been using CP2K to compute excited states with TDDFPT, so far using KERNEL FULL with PBE0 functional.</div><div><br></div><div>I made some tests with STDA and I have some questions with respect to the default parameters. So far I used KERNEL STDA including:</div><div>&STDA</div><div>FRACTION 0.25</div><div>&END</div><div><br></div><div>I was wondering if I should be changing/tuning any other parameter besides the TB HF fraction to get better estimates. For instance so far I used the MATAGA_NISHIMOTO default values but it is said in the manual that they are method dependent.</div><div><br></div><div>Could anyone tell me a little bit more about this?</div><div><br></div><div>Many thanks in advance,</div><div><br></div><div>Maria <br><div><br></div><div><br></div></div>
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