README

(0) Setup Environment

• Copy the executable program and the codes in the Utils directory.
• Paste them into your bin directory.
• You can directly build the DFT-QTC program from SIESTA-DFT-QTC

(1) Setup Calculation (using Example)

1. Copy the original DFT calculation directory into Example/1.dft.

2. Modify origin/RUN.fdf to be comparable with 1.dft/RUN.fdf (note: keep the DFT-half option)

3. Paste all .ion files into the original directory (note: some may already be corrected).

4. Modify the YAML input file input.yaml. The input file is structured as follows:

   • VS_DB:
     Path to the database of all-electron potentials.
     Example:

     VS_DB: "/home3/DB_psf/04.Alpha/01.LDA/30meV"

   • Species:
     Information about the target species. This section includes:

     • DB: Name of the species in the database (used to locate potential files).
     • ION: Name of the ion file to be used for calculation.
     • Occupation: Occupation number correction (usually a fractional value, e.g., -0.30).
       Example:

     Species:
       DB: "C"
       ION: "C"
       Occupation: -0.30

   • Rc:
     Defines the 'outer' cutoff radius scan range. This is used to search for the optimal cutoff parameter.

     • Min: Minimum cutoff radius.
     • Max: Maximum cutoff radius.
     • Npt: Number of sampling points between Min and Max.
       Example:

     Rc:
       Min: 0.0
       Max: 6.0
       Npt: 61

5. Execute:

   python 2.alpha.py

(2) Run Calculation

Submit the job with:

python qsub.py 2.alpha

(3) Obtain Results

1. Get band information:

   python 3.get_bands

   → Generates total.txt with:

   • 1st row: rc (Bohr)
   • 2nd row: HOMO (eV)
   • 3rd row: LUMO (eV)
   • 4th row: band gap (eV)

2. Get total energy:

   python 4.get_total_energy.py

   → Generates total file with:

   • 1st row: rc (Bohr)
   • 2nd row: total energy (eV)

3. The optimal rc is the value that minimizes the total energy.