CP2K Single Point Energy Skill

When to Use

Use this skill when the user wants to:

• Calculate the total energy of a periodic system using CP2K
• Compute electronic density of states with CP2K
• Get forces on atoms without relaxation
• Benchmark different functionals or cutoffs for a crystal structure

CP2K uses the Gaussian and Plane Waves (GPW) method, which is efficient for large periodic systems (100+ atoms). For molecular systems, prefer ORCA.

Default Parameters

Parameter	Default	Description
software	"cp2k"	Must be set to "cp2k"
cp2k_functional	"PBE"	XC functional
cp2k_basis	"DZVP-MOLOPT-SR-GTH"	Gaussian basis set
cp2k_pseudo	"GTH-PBE"	Pseudopotential family
cp2k_cutoff	400	Plane-wave cutoff in Ry
cp2k_rel_cutoff	60	Relative cutoff in Ry
kpoints	[1, 1, 1]	Gamma-point by default

MCP Tool Examples

Basic single point energy

First, check the loaded structure:

catgo_view(action: "get_state")

Create workflow and add single point task:

catgo_workflow_v2(action: "create", params: {
  name: "TiO2 rutile single point"
})

catgo_workflow_v2(action: "add_task", params: {
  workflow_id: "<wf_id>",
  task_type: "single_point",
  params: {
    software: "cp2k",
    cp2k_functional: "PBE",
    cp2k_basis: "DZVP-MOLOPT-SR-GTH",
    cp2k_pseudo: "GTH-PBE",
    cp2k_cutoff: 400
  }
})

With k-points for metals or small cells

catgo_workflow_v2(action: "add_task", params: {
  workflow_id: "<wf_id>",
  task_type: "single_point",
  params: {
    software: "cp2k",
    cp2k_functional: "PBE",
    cp2k_basis: "DZVP-MOLOPT-SR-GTH",
    cp2k_pseudo: "GTH-PBE",
    cp2k_cutoff: 500,
    kpoints: [4, 4, 4]
  }
})

With DFT+U for transition metal oxides

For systems where standard DFT fails (e.g., NiO, FeO, MnO):

catgo_workflow_v2(action: "add_task", params: {
  workflow_id: "<wf_id>",
  task_type: "single_point",
  params: {
    software: "cp2k",
    cp2k_functional: "PBE",
    cp2k_basis: "DZVP-MOLOPT-SR-GTH",
    cp2k_pseudo: "GTH-PBE",
    cp2k_cutoff: 500,
    cp2k_dft_plus_u: true,
    cp2k_u_values: {"Ni": 6.4, "Fe": 4.0}
  }
})

Hybrid functional (HSE06)

More accurate but significantly more expensive:

catgo_workflow_v2(action: "add_task", params: {
  workflow_id: "<wf_id>",
  task_type: "single_point",
  params: {
    software: "cp2k",
    cp2k_functional: "HSE06",
    cp2k_basis: "DZVP-MOLOPT-SR-GTH",
    cp2k_pseudo: "GTH-PBE",
    cp2k_cutoff: 500,
    cp2k_hfx_cutoff_radius: 6.0
  }
})

Submit and get results

catgo_workflow_v2(action: "submit", params: { workflow_id: "<wf_id>" })

catgo_workflow_v2(action: "status", params: { workflow_id: "<wf_id>" })

catgo_workflow_v2(action: "get_result", params: {
  workflow_id: "<wf_id>",
  task_id: "<task_id>"
})

GTH Pseudopotentials

CP2K uses Goedecker-Teter-Hutter (GTH) pseudopotentials. The pseudopotential family MUST match the functional:

Functional	Pseudopotential
PBE	GTH-PBE
BLYP	GTH-BLYP
PBE0, HSE06	GTH-PBE (same PP for hybrids)
SCAN	GTH-SCAN (if available, else GTH-PBE)

Basis set options

Basis	Quality	Atoms	Use
SZV-MOLOPT-SR-GTH	Single-zeta	All	Quick test only
DZVP-MOLOPT-SR-GTH	Double-zeta	All	Production default
TZVP-MOLOPT-SR-GTH	Triple-zeta	Most	Accurate energetics
TZV2P-MOLOPT-SR-GTH	Triple-zeta+2pol	Main group	Benchmark

The -SR- (short range) variants are optimized for condensed phase and are preferred for periodic calculations. -GTH suffix means they match GTH pseudopotentials.

Cutoff Convergence

The plane-wave cutoff (cp2k_cutoff) controls the electron density grid. Test convergence by running multiple single points:

catgo_workflow_v2(action: "add_task", params: {
  workflow_id: "<wf_id>",
  task_type: "single_point",
  task_id: "cut300",
  params: { software: "cp2k", cp2k_cutoff: 300 }
})

Repeat for 400, 500, 600 Ry. Energy should converge to within 1 meV/atom.

Typical converged values:

• Light elements (C, N, O): 400 Ry
• Transition metals: 500 Ry
• Hard pseudopotentials (F, O with certain PPs): 600 Ry

Common Mistakes

• Mismatched basis/pseudopotential families (GTH-PBE basis with BLYP functional)
• Cutoff too low (unconverged energy, meaningless forces)
• Gamma-point k-mesh for a metal (need denser k-points)
• Using molecular basis sets (no -GTH suffix) with GTH pseudopotentials
• Forgetting spin polarization for magnetic systems (set cp2k_spin_polarized: true)