One can calculate any physical properties from the 2-body density-matrix(2-DM). For two electronic states based on the same Hamiltonian, similarly, one can calculate the difference of physical properties from that of the 2-DMs. In this paper, we propose amethod to make comparison between two electronic states. In this method, we use differential natural geminals, which are obtained by a diagonalization of the difference of 2-DMs. Further these geminals are visualized by two-electron correlation plot method. |