SAPT: Symmetry-Adapted Perturbation Theory

SAPT is a collection of computer codes designed to implement the many-body (body = electron) version of Symmetry-Adapted Perturbation Theory for intermolecular interactions. This code has been extensively used in studies of intermolecular forces. For a description of SAPT see: B. Jeziorski, R. Moszynski, and K. Szalewicz “Perturbation Theory Approach to Intermolecular Potential Energy Surfaces of van der Waals Complexes”, Chem. Rev. 94, 1887-1930 (1994). This review article contains references to the original papers where the SAPT methods were developed. Detailed description of the SAPT theory and SAPT code usage is available in the documentation section.

The SAPT suite consists of a few separate programs: serial SAPT, SAPT(DFT), open-shell SAPT(DFT), parallel SAPT, 3-body SAPT, 3-body SAPT(DFT), ATMOL SCF, and asymptotic properties packages. The programs are described on a separate page. A description of capabiliites of these programs can be found in J. Garcia, R. Podeszwa, and K. Szalewicz “SAPT codes for calculations of intermolecular interaction energies”, J. Chem. Phys. 152, 184109 (2020).

SAPT is available free of charge but is not a public domain program. Prospective users should consult the license section for instructions on how to obtain the program.

Former versions (SAPT2006, SAPT2008, SAPT2012, and SAPT2016) can be downloaded from the the download section.


SAPT2020.3 released


SAPT2020.3 has been released. This release of SAPT fixes a serious bug in the COM-COM asymptotics code. Users of this code are urged to upgrade. The release brings also a few minor enhancements Read more...

UPACK patch released


A patch of UPACK for using SAPT force fields (developed using autoPES) in crystal structure predictions. Click here to download patch.

SAPT2020.2 released


SAPT2020.2 has been released. This release of SAPT adds several quality-of-life improvements to the fastdf program, such as the possibility of using different functionals for first- and second-order contributions, and the automatic computation of ionization potntentials. It also has improvements on the I/O performance in several subroutines. Read more...

SAPT2020.1.2 released


SAPT2020.1.2 has been released. This release of SAPT adds some scripts for using the distributed asymptotic programs and fixes ATMOL1024 compatibility with newer gfortran versions. Read more...

AutoPES-2020.1 released


autoPES-2020.1 has been released.

SAPT2020.1 released


SAPT2020.1 has been released. This release of SAPT contains fastdf, a new FORTRAN program designed to compute SAPT(DFT) interaction energies easily and efficiently. Read more...