Linear-scaling computation of ground state with time-domain localized-density-matrix method

Recently developed time-domain localized-density-matrix (LDM) method for calculating the electronic excited-state properties has been applied to calculate the electronic ground state. The computational time remains to scale linearly with the system size. To test the method, we use it to determine the ground states of polyacetylene oligomers containing up to 20000 carbon atoms. The Pariser–Parr–Pople (PPP) Hamiltonian is employed for the π electrons of the systems. Comparison to the conventional diagonalization shows the high efficiency as well as accuracy of the time-domain LDM method.