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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 Al2 atoms 1 and 2

For Al2 (Aluminum 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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ cc-pCVDZ cc-pCVTZ
Moller Plesset perturbation MP2=FULL 0.0019 -0.0023 0.0045 -0.0014 -0.0684 0.0064 0.0037 -0.0933 0.0000 0.0314 0.0062 0.0220 -0.1932 0.0057 0.0036 0.0061 0.0099
MP3=FULL         0.0816   0.0107                    
B2PLYP=FULL         0.1665                        
Coupled Cluster CCSD(T)=FULL         0.0070           0.0089 0.0207 0.0161 0.0095 0.0350 0.0063 0.0074
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-pVTZ cc-pCVDZ cc-pCVTZ

al2q1.gif