A spin-adapted implementation of DMRG for ab initio quantum chemistry
Description
The CheMPS2 library provides a free open-source spin-adapted
implementation of the density matrix renormalization group (DMRG) for ab initio
quantum chemistry. This method allows to obtain numerical accuracy in active
spaces beyond the capabilities of full configuration interaction. For the
input Hamiltonian and targeted symmetry sector, the library performs successive
DMRG sweeps according to a user-defined convergence scheme. As output, the
library returns the minimal encountered energy as well as the 2-RDM of the
active space. The latter allows to calculate various properties, as well as
the gradient and Hessian for orbital rotations or nuclear displacements.
