  The practical utility of M{\o}ller-Plesset (MP) perturbation theory is
severely constrained by the use of Hartree-Fock (HF) orbitals. It has recently
been shown that use of regularized orbital-optimized MP2 orbitals and scaling
of MP3 energy could lead to a significant reduction in MP3 error (J. Phys.
Chem. Lett. 10, 4170, 2019). In this work we examine whether density functional
theory (DFT) optimized orbitals can be similarly employed to improve the
performance of MP theory at both the MP2 and MP3 levels. We find that use of
DFT orbitals leads to significantly improved performance for prediction of
thermochemistry, barrier heights, non-covalent interactions, and dipole moments
relative to standard HF based MP theory. Indeed MP3 (with or without scaling)
with DFT orbitals is found to surpass the accuracy of coupled cluster singles
and doubles (CCSD) for several datasets. We also found that the results are not
particularly functional sensitive in most cases, (although range-separated
hybrid functionals with low delocalization error perform the best). MP3 based
on DFT orbitals thus appears to be an efficient, non-iterative $O(N^6)$ scaling
wave function approach for single-reference electronic structure computations.
Scaled MP2 with DFT orbitals is also found to be quite accurate in many cases,
although modern double hybrid functionals are likely to be considerably more
accurate.
