SCINE - XTB Wrapper -- A Wrapper for Tight Binding

Introduction

SCINE XTB Wrapper is a wrapper around xtb, it exports:

• GFN0-xTB
• GFN1-xTB (formerly GFN-xTB)
• GFN2-xTB
• GFN-FF

into the SCINE tool chain. Each method is represented by its own Calculator and the entire wrapper constitutes a SCINE module that can be loaded dynamically at runtime. For more information on these concepts see the Scine::Core repository.

License and Copyright Information

The SCINE XTB wrapper is distributed under the BSD 3-clause "New" or "Revised" License. For more license and copyright information, see the file LICENSE.txt in the repository.

Note: this license does not cover the original xtb source code. For the copyright information of the xtb code please follow the linked git submodule to the developers' repository.

Installation and Usage

The wrapper can be built and installed using the following commands:

mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=<desired path> ..
make -j<number of cores to use>
make install

This will generate and install both the main xtb code and the wrapper in the form of the file xtb.module.so that can be used in SCINE.

In order to make XTB available to SCINE the following two environment variables need to be set:

export XTBPATH=<prefix-path>/share/xtb
export SCINE_MODULE_PATH=$SCINE_MODULE_PATH:<prefix-path>/lib

Afterwards, SCINE programs such as ReaDuct will pick up XTB's existence and it will be possible to request the implemented methods.

Python

The SCINE XTB wrapper is also available via Python. The underlying SCINE module can be loaded and its implemented calculators accessed using the standard scine_utilities Python bindings. A minimal workflow could look like this:

import scine_utilities as su
import scine_xtb_wrapper

# Generate Structure
structure = su.AtomCollection()
structure.elements = [su.ElementType.H, su.ElementType.H]
structure.positions = [[-0.7, 0, 0], [0.7, 0, 0]]

# Get calculator
manager = su.core.ModuleManager()
calculator = manager.get('calculator', 'GFN2')

# Configure calculator
calculator.structure = structure
calculator.set_required_properties([su.Property.Energy, su.Property.Gradients])

# Calculate
results = calculator.calculate()
print(results.energy)
print(results.gradients)

How to Cite

When publishing results obtained with SCINE we kindly ask you to cite the appropriate references, e.g. the one for ReaDuct. This wrapper does not have its own reference; it should also not be mistaken for the actual xtb code it wraps.

For the latter code and its citations, we refer you to the original xtb repository. There you will find the references of the actual methods used. They are listed in the README.md.

Support and Contact

In case you should encounter problems or bugs with the wrapper, please write a short message to scine@phys.chem.ethz.ch.