Lec:8 DFT-D Dispersion Corrections | CASTEP | Properties Tab | Job control | Material studio

CASTEP Tutorial | Electronic → DFT-D Dispersion Corrections Explained
Welcome to Lecture 8 of the CASTEP Full Series!
In this lecture, we focus on the DFT-D (dispersion correction) tab in CASTEP’s Electronic Options. Standard DFT methods (like LDA and GGA) often fail to capture van der Waals (vdW) interactions accurately. These weak, long-range forces are essential for describing layered materials, molecular crystals, adsorption processes, and biomolecular interactions.
CASTEP provides built-in DFT-D correction schemes to account for these interactions. In this video, we break down every option available in the DFT-D tab so you know why it exists, what it controls, and how to use it in practice.
🔎 What you will learn in this lecture
🌌 1. Why dispersion corrections are needed
The limitations of conventional DFT (LDA/GGA) in modeling vdW interactions.
Real-world systems where vdW forces matter: graphite, graphene, organic crystals, molecular adsorption, hybrid perovskites, and surface science.
How DFT-D augments standard DFT with semi-empirical corrections.
⚙️ 2. Using Custom DFT-D Parameters
Enabling the “Use custom” option to activate dispersion corrections.
When to turn this on (organic/inorganic hybrid systems, weakly bonded materials, physisorption studies).
📂 3. Scheme Selection (TS, Grimme, OBS, etc.)
TS (Tkatchenko–Scheffler): Modern, environment-dependent, accurate for solid-state systems.
Grimme D2/D3: Widely used semi-empirical corrections, popular in molecular and organic simulations.
OBS: An older scheme, rarely used today.
Best practices: Which scheme to choose depending on your system.
4. Atomic Parameters (C6, R0, α)
C6 (eV·Å⁶) → strength of dispersion interaction.
R0 (Å) → vdW radius, setting distance scaling.
α (ų) → polarizability, linked to how atoms respond to electric fields.
CASTEP assigns these automatically per atom (example: Ta in your screenshot). Advanced users may adjust them when comparing against experimental data.
How to enable DFT-D for a layered material like MoS₂ or graphite.
When dispersion corrections are crucial for adsorption energies and interlayer binding.
✅ Best practices for researchers
Always enable DFT-D corrections when studying vdW-dominated systems.
For inorganic solids without weak bonding → corrections may have small effect but still improve accuracy.
Report which scheme (TS, D2, D3, etc.) you used in your publications.
If comparing with experimental lattice constants or binding energies, DFT-D often brings DFT results closer to experiment.
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Видео Lec:8 DFT-D Dispersion Corrections | CASTEP | Properties Tab | Job control | Material studio канала SoftSkill Academy