May 26, 2018
Spin-adapted implementation of DMRG for ab initio quantum chemistry
CheMPS2 is a scientific library which contains a spin-adapted implementation of the density matrix renormalization group DMRG for ab initio quantum chemistry. This wavefunction method allows to obtain numerical accuracy in active spaces beyond the capabilities of full configuration interaction FCI, and allows to extract the 2-, 3-, and 4-particle reduced density matrices 2-, 3- and 4-RDM of the active space.
For general active spaces up to 40 electrons in 40 orbitals can be handled with DMRG, and for one-dimensional active spaces up to 100 electrons in 100 orbitals. The 2-RDM of these active spaces can also be easily extracted, while the 3- and 4-RDM are limited to about 28 orbitals.