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

For C4H4N (pyrrolide radical)

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) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ
Moller Plesset perturbation MP2=FULL -0.001878 -0.008385 -0.008385 -0.006461 -0.022916 -0.023578 -0.024214 -0.093370 -0.093984 -0.039730 -0.085151 -0.012130 -0.075513 -0.014088 -0.089299
MP3=FULL         -0.022506   -0.023822       -0.088981 -0.011383 -0.077528    
MP4=FULL         -0.022575       -0.097960     -0.011367 -0.077911 -0.013303 -0.092838
B2PLYP=FULL -0.000574 -0.002509 -0.002509 -0.001929 -0.006755 -0.006944 -0.007131 -0.026678 -0.026863 -0.011521 -0.024354 -0.003599 -0.021850 -0.004174 -0.025753
Coupled Cluster CCSD=FULL         -0.022181           -0.088792 -0.011080 -0.076900 -0.012972 -0.091784
CCSD(T)=FULL         -0.022460           -0.089378 -0.011260 -0.077558 -0.013169 -0.047752
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) TZVP cc-pVDZ cc-pVTZ aug-cc-pVDZ aug-cc-pVTZ