ΔSCF-DFT and MolPDOS is a module for the CASTEP electronic structure code, developed by Prof. Reinhard J. Maurer, enabling calculations of excited states and molecular orbital analysis.
Overview
This module extends the capabilities of CASTEP, a leading plane-wave DFT code, to:
- Calculate approximate excited states using ΔSCF (delta self-consistent field) methods
- Project the density of states onto molecular orbitals (MolPDOS)
These capabilities are essential for understanding electronic structure, optical properties, and charge transfer in molecules and materials.
ΔSCF Method
What is ΔSCF?
ΔSCF (delta SCF) is a computational approach for excited states where:
- Ground state is calculated with standard DFT
- Excited state is calculated by occupying higher energy orbitals
- Excitation energy = Energy difference between states
MolPDOS: Molecular Projected Density of States
MolPDOS projects the electronic density of states onto molecular orbital basis:
- Identifies molecular orbital character in solid-state calculations
- Tracks hybridization between molecule and substrate
- Analyzes charge transfer and bonding
- Visualizes frontier orbital evolution
Development and Availability
First released in 2016, this module has been integrated into the main CASTEP codebase and is available to all CASTEP users.
Documentation
Users can find documentation in:
- CASTEP user manual
- CASTEP online documentation
- Research publications by Maurer and Reuter
Citation
When using this module, please cite:
Maurer, R. J., & Reuter, K. (2016). Excited-state potential-energy surfaces of metal-adsorbed organic molecules from linear expansion Δ-self-consistent field density-functional theory (ΔSCF-DFT). Journal of Chemical Physics 139, 014708 (2013)