Overview

Forte is an open-source suite of state-of-the-art quantum chemistry methods applicable to chemical systems with strongly correlated electrons. The code is written as a plugin to Psi4 in C++ with C++17 functionality, and it takes advantage of shared memory parallelism throughout.

Capabilities

In general, Forte is composed of two types of methods: 1. Active space solvers 1. Dynamical correlation solvers

Active space solvers	Abbreviation
Full/complete active space configuration interaction	FCI/CASCI
Adaptive configuration interaction	ACI
Projector configuration interaction	PCI

Dynamical correlation solvers	Abbreviation
Driven similarity renormalization group	DSRG
Second-order DSRG multireference perturbation theory	DSRG-MRPT2
Third-order DSRG multireference perturbation theory	DSRG-MRPT3
Multireference DSRG with singles and doubles	MR-LDSRG(2)

Note that the active space solvers, notably FCI, ACI, and PCI can operate within the full orbital basis defined by the user-selected basis set. In this case, these methods also recover dynamical correlation.

Dependencies

In order to run Forte, the following are required: - A Recent version of Psi4 - CMake version 3.0 or higher - The tensor library Ambit