Second-order many-body perturbation theory (MP2) computes the ground state of a many-electron atom or molecule with the correlation energy treated by a second-order perturbation expansion around the Hartree-Fock energy.

MP2 is non-variational, meaning that its energy is not necessarily an upper bound to the full CI energy in a given basis set.

basis = string -- name of the basis set.  See Basis for a list of available basis sets.  Default is "sto-3g".

spin = nonnegint -- twice the total spin S (= 2S). Default is 0.

charge = nonnegint -- net charge of the molecule. Default is 0.

symmetry = string/boolean -- is the Schoenflies symbol of the abelian point-group symmetry which can be one of the following:  D2h, C2h, C2v, D2, Cs, Ci, C2, C1. true finds the appropriate symmetry while false (default) does not use symmetry.

unit = string -- "Angstrom" or "Bohr". Default is "Angstrom".

max_memory = posint -- allowed memory in MB. Default is 4000.

ghost = list of lists -- each list has the string of an atom's symbol and the atom's x, y, and z coordinates.  See Ghost Atoms.

initial_mo = Matrix -- Matrix of MOs (columns) in terms of atomic orbitals (rows) that defines the MO basis set.

nuclear_gradient = boolean -- option to return the analytical nuclear gradient if available. Default is false.

return_rdm = string -- options to return the 1-RDM and/or 2-RDM: "none", "rdm1", "rdm1_and_rdm2". Default is "rdm1".

populations = string -- atomic-orbital population analysis: "Mulliken" and "Mulliken/meta-Lowdin". Default is "Mulliken".

Attributes for Hartree Fock:

conv_tol_hf = float -- converge threshold. Default is ${10}^{-10}\.$

diis_hf = boolean -- whether to employ diis. Default is true.

diis_space_hf = posint -- diis's space size. By default, 8 Fock matrices and error vectors are stored.

diis_start_cycle_hf = posint -- the step to start diis. Default is 1.

direct_scf_hf = boolean -- direct SCF in which integrals are recomputed is used by default.

direct_scf_tol_hf = float -- direct SCF cutoff threshold. Default is ${10}^{-13}\.$

level_shift_hf = float/int -- level shift (in au) for virtual space. Default is $0.$

max_cycle_hf = posint -- max number of iterations. Default is 50.

max_memory_scf_hf = posint -- allowed memory in MB. Default is 4000.

nuclear_gradient_hf = boolean -- option to return the analytical nuclear gradient. Default is false.

populations_hf = string -- atomic-orbital population analysis: "Mulliken" and "Mulliken/meta-Lowdin". Default is "Mulliken".

C. Møller and M. S. Plesset, Phys. Rev. 46, 618–622 (1934). "Note on an Approximation Treatment for Many-Electron Systems"

A. Szabo and N. S. Ostlund, Modern Quantum Chemistry: Introduction to Advanced Electronic Structure Theory (Dover Books, New York, 1996).

$\mathrm{with}\left(\mathrm{QuantumChemistry}\right)\:$

$\mathrm{molecule} ≔ \left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95\right]\right]\;$

$\mathrm{molecule}≔\left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95000000\right]\right]$

$\mathrm{output\_hf} ≔ \mathrm{MP2}\left(\mathrm{molecule}\,\mathrm{basis}\=''dz''\right)\;$