“…83,[108][109][110][111]129,130 To arrive at this step, we first note that under conditions of "adiabatic control'' 84,109,110,131 extended Lagrangian formalisms 132,133 such as ADMP provide good approximations to single-particle (Hartree-Fock, DFT, and semiempirical treatments) BornOppenheimer molecular dynamics (BOMD). 11,13,109 When ADMP is used to describe the dynamics of the electrons, subsystem C is described through propagation of the single-particle electronic density matrix, P C , as Here, µ is a fictitious inertia tensor 83,[108][109][110] describing the motion of P C , and Λ is a Lagrangian multiplier matrix used to impose N-representability of P C .…”