adf2stowf 1.0.0

Converter from ADF TAPE21.asc to CASINO stowfn.data

adf2stowf

Converts wave function data from the ADF (Amsterdam Density Functional) program into the stowfn.data input file for the CASINO quantum Monte Carlo code.

ADF is the only major quantum chemistry program that uses Slater-Type Orbitals (STO) natively. CASINO can use them directly by setting:

atom_basis_type : slater-type

in the CASINO input file, which makes ADF+CASINO a powerful combination for high-accuracy QMC calculations.

For general information about ADF, see https://www.scm.com/ For CASINO, see https://vallico.net/casinoqmc/

Requirements

• Python >= 3.10
• NumPy >= 2.0.0
• SciPy >= 1.13.1
• Matplotlib >= 3.9.0 (optional, for --plot-cusps)

Installation

pip install adf2stowf

or from source:

git clone https://github.com/Konjkov/adf2stowf
cd adf2stowf
pip install .

Usage

1. Run ADF:

   adf < adf.in > adf.out
   

   This produces a binary file TAPE21 in the working directory.

2. Convert to ASCII format using the dmpkf utility (included with ADF):

   dmpkf TAPE21 > TAPE21.asc
   

3. Run the converter in the same directory:

   adf2stowf
   

   This reads TAPE21.asc and writes stowfn.data.

Command-line options

Option	Description
--cusp-method=enforce	Apply cusp correction to active orbitals (default)
--cusp-method=project	Project out cusp-violating components
--cusp-method=none	Disable cusp correction
--cart2harm-projection	Enforce pure spherical harmonics via orthogonal projection
--all-orbitals	Include virtual orbitals (default: occupied only)
--plot-cusps	Plot cusp constraints (requires Matplotlib)
--dump	Write a text dump of TAPE21 to TAPE21.txt

Cartesian-to-spherical warning

You may see a warning during conversion:

WARNING: cartesian to spherical conversion for spin 0, orb 0 violated by 0.00063567

ADF computes MOs in a Cartesian basis (6 d-functions, 10 f-functions). CASINO requires pure spherical harmonics (5 d, 7 f). The extra Cartesian components (e.g. the s-type contamination x²+y²+z² in d-shells) are unphysical in a spherical harmonic representation.

Use --cart2harm-projection to remove these components via an orthogonal projection onto the pure spherical harmonic subspace. Without it, the contaminating components are silently dropped, which may slightly affect the total energy.

Testing

Reference output files for all example systems are included in examples/. To run the regression tests:

pip install pytest
pytest tests/test_regression.py -v

Each test runs the full conversion pipeline on examples/<system>/TAPE21.asc and compares the result against the reference stowfn.data.

Documentation

Full documentation including mathematical background (cusp conditions, Cartesian-to-spherical transformation matrices) is available at https://adf2stowf.readthedocs.io/en/latest/

To build locally:

pip install sphinx sphinx-rtd-theme
cd docs && make html