dftfe-phonons

A Python utility that connects Phonopy and DFT-FE workflows. This script automates:

1. Preparing DFT-FE inputs for each displaced supercell (domainBoundingVectors.inp and coordinates.inp)
2. Reading DFT-FE forces and assembling a valid Phonopy FORCE_SETS file

Designed for large-scale phonon calculations using DFT-FE as the DFT backend and Phonopy for post-processing.

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Features

✅ Prepare DFT-FE Inputs

For each POSCAR-* displaced structure:

• Converts VASP POSCAR to DFT-FE format
• Writes:
  • domainBoundingVectors.inp (in Bohr)
  • coordinates.inp (fractional positions, valence info, optional magnetism)
• Supports interactive or JSON-driven valence electron specification
• Supports magnetic or non-magnetic calculations
• Works with PhonopyAtoms from old and new Phonopy versions

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✅ Generate Phonopy FORCE_SETS

Given:

• Reference structure (SPOSCAR)
• Per-displacement DFT-FE force files (forces.txt)

The script:

• Detects the displaced atom
• Converts forces to eV/Å
• Writes Type-1 FORCE_SETS compatible with Phonopy
• Handles Ha/Bohr → eV/Å conversion automatically

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Installation

Requirements

• Python 3.8+
• phonopy ≥ 2.3
• numpy

Install dependencies:

pip install phonopy numpy

Clone this repository:

git clone https://github.com/<your-username>/dftfe-phonons.git
cd dftfe-phonons

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Usage

The script provides two modes:

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1. Prepare DFT-FE Inputs

python dftfe-phonons.py --prepare_input

This mode:

• Scans for POSCAR-* files
• Detects all unique elements
• Prompts for valence electrons
• Prompts for magnetism settings
• Generates folders:

dftfe_in/POSCAR-001/
dftfe_in/POSCAR-002/
...

Each contains:

domainBoundingVectors.inp
coordinates.inp

Optional arguments

Flag	Description
--zvalence-json file.json	Use a JSON mapping instead of interactive input
--magnetic --magvalue X	Non-interactive global magnetization
--poscar-glob "POSCAR-*"	Custom glob for displaced structures
--out-root name	Base directory for output

Example JSON file

{
  "Fe": [26, 8],
  "C": [6, 4]
}

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2. Build FORCE_SETS from DFT-FE Forces

python dftfe-phonons.py --read_force --reference SPOSCAR

What it does

• Reads the reference supercell (SPOSCAR)
• Reads each displaced POSCAR-*
• Detects which atom moved
• Reads forces from:

dftfe_in/POSCAR-001/forces.txt

• Converts units
• Writes a complete FORCE_SETS file

Optional arguments

Flag	Description
--forces-filename	Default: forces.txt
--force-unit	Ha/Bohr (default) or eV/Ang
--output	Output FORCE_SETS filename
--poscar-glob	Pattern for displaced POSCARs

Example:

python dftfe-phonons.py --read_force     --reference SPOSCAR     --force-unit Ha/Bohr     --output FORCE_SETS

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Input File Layout

Your directory should look like:

SPOSCAR
POSCAR-001
POSCAR-002
...
dftfe-phonons.py

After --prepare_input, you get:

dftfe_in/
    POSCAR-001/
        domainBoundingVectors.inp
        coordinates.inp
    POSCAR-002/
        ...

Run your DFT-FE calculations inside each folder, producing forces.txt.

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