Dear Jürg,
Thank you for your response! I am working on optimizing the geometry of 8 guanine molecules coordinated around a potassium ion. I performed geometry optimization calculations and obtained a structure similar to the one obtained in X-ray structural analysis. The issue is that the distance between the planes of guanine pairs, stacked on top of each other, is 3.0 Å according to experimental data, but in the calculations, it turned out to be 4.5 Å. I found in one of the CP2K tutorials (https://www.cp2k.org/_media/events:2015_cecam_tutorial:ling_vdw.pdf) that such a situation is possible when dispersion interactions are not taken into account. It was mentioned that including van der Waals interactions is possible by using the dftd3 method and specifying the dftd3.dat file, which is provided in the CP2K package. I searched for information about dftd3 and came across the corresponding package, which led to the question of whether it is possible to generate a similar dftd3.dat file using this package to use it in geometry optimization within CP2K.
In the end, I am facing the problem of not fully understanding how to correctly account for dispersion interactions, which are crucial for my structure.
Best regards, S.S. Bachurin