Applications of Time-Dependent Density-Matrix Approach

Localized-density-matrix implementation of time-dependent density-functional theory

Adiabatic approximation of time-dependent density matrix functional response theory.

Time-dependent density matrix functional theory can be formulated in terms of coupled-perturbed response equations, in which a coupling matrix K(omega) features, analogous to the well-known time-dependent density functional theory (TDDFT) case. An adiabatic approximation is needed to solve these equations, but the adiabatic approximation is much more critical since there is not a good "zero ord...

The Density Matrix Renormalization Group and its time-dependent variants

Since its creation in 1992, the density matrix renormalization group (DMRG) method [1] has evolved and mutated. From its original formulation in a condensed matter context, it has been adapted to study problems in verious fields, such as nuclear physics and quantum chemistry, to become one of the dominant numerical methods to study strongly correlated systems. The purpose of these lectures is t...

Semiclassical Correlation in Time-Dependent Density Matrix Functional Theory

The impact of time-dependent density functional theory (TDDFT) [1, 2] on calculations of excitation spectra and response in atoms, molecules, and solids is evident in its increasing use. In such applications a weak perturbation is applied to the system beginning in its ground state, and usually the exchange-correlation (xc) effects are treated with a ground-state approximation. Generally the re...

The spin–flip approach within time-dependent density functional theory: Theory and applications to diradicals

An extension of density functional theory to situations with significant nondynamical correlation is presented. The method is based on the spin–flip ~SF! approach which is capable of describing multireference wave functions within a single reference formalism as spin–flipping, e.g., a→b, excitations from a high-spin (M s51) triplet reference state. An implementation of the spin–flip approach wi...