Guidance for New User Transitioning from VASP to CP2K

[Zhiyuan Yin]

Dear CP2K community,

I am a new user transitioning my research workflows from VASP to CP2K, primarily for DFT-D3(BJ) corrected geometry optimizations and molecular dynamics simulations involving slab + molecule systems.

As I’m getting started, I would greatly appreciate the community’s advice on a few beginner-oriented questions:

1. For systems involving heavy metal slabs (e.g., Ag) and adsorbed organic molecules, are there any recommended default settings or best practices to ensure convergence and efficiency?
2. Is `DZVP-MOLOPT-SR-GTH` generally preferred over `TZVP-MOLOPT-GTH` for surface + molecule systems in terms of balancing accuracy and computational cost?
3. For modeling slab systems with vacuum along Z (non-periodic in Z), is `PERIODIC XY` the correct and sufficient setting in the `&CELL` section?
4. Are there any example inputs or benchmark systems involving metal slabs and dispersion-corrected adsorption that I could study as references?

Any advice, example inputs, or references that you could share would be extremely helpful as I transition to CP2K. Thank you very much in advance for your time and support!

Best regards,  
Zhiyuan Yin

[Marcella Iannuzzi]

Dear Zhiyuan Yin,

For metallic systems,  the standard diagonalization approach, with smearing of the occupation number and G-space density mixing are recommended.

You can test different eigensolvers: https://manual.cp2k.org/trunk/technologies/eigensolvers/index.html

Periodic in 3D with sufficient vacuum should also work fine.

The basis set choice depends on the accuracy/efficiency compromise, TZVP might be better for adsorption.

For the dispersion correction there are also other methods in addition to D3, the choice might also depend on the functional.

Regards

Marcella