title: Communication: Active space decomposition with multiple sites: density matrix renormalization group algorithm.
abstract: We extend the active space decomposition method, recently developed by us, to more than two active sites using the density matrix renormalization group algorithm. The fragment wave functions are described by complete or restricted active-space wave functions. Numerical results are shown on a benzene pentamer and a perylene diimide trimer. It is found that the truncation errors in our method decrease almost exponentially with respect to the number of renormalization states M, allowing for numerically exact calculations (to a few μE(h) or less) with M = 128 in both cases. This rapid convergence is because the renormalization steps are used only for the interfragment electron correlation.
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208, USA.
authors.forename: Shane M
authors.initials: SM
authors.lastname: Parker
authors.affiliation: Department of Chemistry, Northwestern University, 2145 Sheridan Rd., Evanston, Illinois 60208, USA.
authors.forename: Toru
authors.initials: T
authors.lastname: Shiozaki