Density
matrix e
mbedding theory (DMET) (Knizia, G.; Chan, G. K.-L.
Phys. Rev. Lett. 2012,
109, 186404) provides a theoretical fra
mework to treat finite frag
ments in the presence of a surrounding
molecular or bulk environ
ment, even when there is significant correlation or entangle
ment between the two. In this work, we give a practically oriented and explicit description of the nu
merical and theoretical for
mulation of DMET. We also describe in detail how to perfor
m self-consistent DMET opti
mizations. We explore different e
mbedding strategies with and without a self-consistency condition in hydrogen rings, berylliu
m rings, and a sa
mple S
N2 reaction. The source code for the calculations in this work can be obtained fro
m m/sebwouters/qc-dmet" class="extLink">https://github.com/sebwouters/qc-dmet.