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Bond Length differences between FULL (all electrons correlated) and FROZEN core

Such as MP2=Frozen and MP2=Full
17 10 27 16 27

For As2 atoms 1 and 2

For As2 (Arsenic diatomic)
Bond length differences (full - frozen) in Å. Mouse over a difference for the bond length with full correlation.
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 aug-cc-pVDZ aug-cc-pVTZ
Moller Plesset perturbation MP2=FULL 0.0009 -0.0002 0.0023 0.0023 0.0112 0.0096 0.0094 0.0131 0.0124 0.0307 0.0027 0.0075 0.0023 0.0124
MP3=FULL         0.0062   0.0019              
Coupled Cluster CCSD(T)=FULL         0.0074           0.0024 0.0056 0.0021 0.0108
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 aug-cc-pVDZ aug-cc-pVTZ

as2.gif