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Energy differences between frozen core and all electrons correlated.
MP2, MP3, MP4, B2PLYP, CCSD, and CCSD(T)

For BeH+ (beryllium monohydride cation)

Energies in Hartree
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVQZ cc-pV(T+d)Z
Moller Plesset perturbation MP2=FULL -0.000322 -0.000661 -0.000661 -0.000725 -0.003217 -0.003295 -0.003360 -0.014416 -0.014549 -0.002284 -0.000668 -0.006445 -0.020080 -0.001040 -0.020644 -0.006445
MP3=FULL         -0.003395   -0.003673                  
Coupled Cluster CCSD(T)=FULL         -0.003414               -0.022196   -0.022810  
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVQZ cc-pV(T+d)Z