name	calls method in Stanton and Gauss’s CFOUR program [manual]
c4-scf	Hartree–Fock (HF)
c4-mp2	2nd-order Møller–Plesset perturbation theory (non-density-fitting) (MP2)
c4-mp3	3rd-order Møller–Plesset perturbation theory (MP3)
c4-mp4(sdq)	4th-order MP perturbation theory (MP4) less triples
c4-mp4	full MP4
c4-cc2	approximate coupled cluster singles and doubles (CC2)
c4-ccsd	coupled cluster singles and doubles (CCSD)
c4-cc3	approximate CC singles, doubles, and triples (CC3)
c4-ccsd(t)	CCSD with perturbative triples (CCSD(T))
c4-ccsdt	coupled cluster singles, doubles, and triples (CCSDT)
cfour	expert full control over cfour program