Spin-adapted coupled-cluster theory for the treatment of low-spin open-shell states

点击翻译按钮获取中文摘要

To extend the applicability of coupled-cluster theory in quantum chemical (multi-reference) cases is proposed. The initial focus will be on open-shell singlet states (i.e. biradicals) requiring at least two reference determinants. A spin-adapted scheme is suggested based on the projection of Schrödinger and spin eigenvalue equations onto excited configuration functions. For chemical applications, a computer program will be developed that allows the efficient computation of molecular energies and properties.