The electron delocalization range in stretched bonds

The electron delocalization range function EDR((r) over right arrow ,d) (Janesko et al., J. Chem. Phys. 2014, 141, 144104) quantifies the width of the one-particle density matrix about point (r) over right arrow, measuring aspects of delocalization. Here, we explore the EDR in stretched and compressed chemical bonds. The EDR illustrates how compressing chemical bonds localizes the one-particle density matrix about the reference point, and captures aspects of fractional occupancy, and left-right correlation in stretched covalent bonds.