Semiempirical Extended Tight-Binding Program Package

This is the offical repository of the xtb program package developed by the Grimme group in Bonn.

Installation

Statically linked binaries (Intel Compiler 17.0.7) can be found at the latest release page. There is also a version of the shared library, which requires the Math Kernel Library and additional Intel specific libraries to be installed.

xtb is routinely compiled with Intel Parallel Studio 17 on our clusters in Bonn, successful builds on OSX have been performed as well. We have not tried to build xtb on Windows so far. It is also possible to compile xtb with GCC (version 8), but we recommend to use binaries compiled with Intel.

This projects supports two build systems, meson and CMake. A short guide on the usage of each is given here, follow the linked instructions for a more detailed information (meson guide, CMake guide).

Meson

Using meson as build system requires you to install a fairly new version like 0.51 or newer. To use the default backend of meson you have to install ninja version 1.7 or newer.

export FC=ifort CC=icc
meson setup build --buildtype release --optimization 2
ninja -C build test

Make sure the testsuite is running without errors.

To install the xtb binaries to /usr/local use (might require sudo)

ninja -C build install

For more information on the build with meson see the instructions here.

CMake

The CMake build system requires both make and CMake to be installed, the latter has to be version 3.9 or newer.

Building xtb with CMake works with the following chain of commands:

mkdir build
pushd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make
ctest
popd

To install the xtb binaries to /usr/local use (might require sudo)

make -C build install

For more detailed information on the build with CMake see the instructions here.

Conda

Installing xtb from the conda-forge channel can be achieved by adding conda-forge to your channels with:

conda config --add channels conda-forge

Once the conda-forge channel has been enabled, xtb can be installed with:

conda install xtb

It is possible to list all of the versions of xtb available on your platform with:

conda search xtb --channel conda-forge

Documentation

The xtb documentation is hosted at read-the-docs.

Contributing

See our contributing guidelines.

Citations

General Reference to xtb and the implemented GFN methods:

• C. Bannwarth, E. Caldeweyher, S. Ehlert, A. Hansen, P. Pracht, J. Seibert, S. Spicher, S. Grimme WIREs Comput. Mol. Sci., 2020, e01493. DOI: 10.1002/wcms.1493

for GFN-xTB:

• S. Grimme, C. Bannwarth, P. Shushkov, J. Chem. Theory Comput., 2017, 13, 1989-2009. DOI: 10.1021/acs.jctc.7b00118
• C. Bannwarth, S. Ehlert and S. Grimme., J. Chem. Theory Comput., 2019, 15, 1652-1671. DOI: 10.1021/acs.jctc.8b01176
• P. Pracht, E. Caldeweyher, S. Ehlert, S. Grimme, ChemRxiv, 2019, preprint. DOI: 10.26434/chemrxiv.8326202.v1

for GFN-FF:

• S. Spicher and S. Grimme, Angew. Chem. Int. Ed., 2020, accepted article. DOI: 10.1002/anie.202004239

for DFT-D4:

• E. Caldeweyher, C. Bannwarth and S. Grimme, J. Chem. Phys., 2017, 147, 034112. DOI: 10.1063/1.4993215
• E. Caldeweyher, S. Ehlert, A. Hansen, H. Neugebauer, S. Spicher, C. Bannwarth and S. Grimme, J. Chem. Phys., 2019, 150, 154122. DOI: 10.1063/1.5090222
• E. Caldeweyher, J.-M. Mewes, S. Ehlert and S. Grimme, Phys. Chem. Chem. Phys., 2020, 22, 8499-8512. DOI: 10.1039/D0CP00502A

for sTDA-xTB:

• S. Grimme and C. Bannwarth, J. Chem. Phys., 2016, 145, 054103. DOI: 10.1063/1.4959605

in the mass-spec context:

• V. Asgeirsson, C. Bauer and S. Grimme, Chem. Sci., 2017, 8, 4879. DOI: 10.1039/c7sc00601b
• J. Koopman and S. Grimme, ACS Omega, 2019, 4, 12, 15120-15133. DOI: 10.1021/acsomega.9b02011

for metadynamics refer to:

• S. Grimme, J. Chem. Theory Comput., 2019, 155, 2847-2862. DOI: 10.1021/acs.jctc.9b00143

All references are available in bibtex format.

License

xtb is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

xtb is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the GNU Lesser General Public License for more details.