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.

To compile xtb from source install Intel Parallel Studio 17 or later.

We are using meson as build system and require you to install a fairly new version like 0.49 or newer. To use the default backend of meson you have to install ninja version 1.5 or newer.

export FC=ifort CC=icc CXX=icpc
meson setup build_intel --optimization=2
ninja -C build_intel test

Make sure the testsuite is running without errors. xtb is routinely compiled with Intel Parallel Studio 17 on our clusters in Bonn, but we have not tried to compile it on either OSX or Windows so far. Also you currently cannot compile xtb with GCC and there is no plan to support it in the near future.

Documentation

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

Contributing

See our contributing guidelines.

Citations

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 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

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

for metadynamics refer to:

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

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.