In the demonstrations of the algorithm presented here, we will use tighter cutoffs in order to best capture the effects of non-covalent interations. We present results using T CU T P N O = 10 -7 , T CUT ENERGY = 0.997, and T CUT TRACE = 0.999. The occupation criterion was the original method of truncating PNOs introduced by Riplinger et al. in the ORCA package in the DLPNO-CCSD algorithm. The energy criterion was first introduced by the work of Schwilk et al. in the Molpro package in their PNO-LCCSD algorithm. After the truncated PNO basis is constructed, the truncated PNOs are canonicalized to give orbital energies for the pair ij.