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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 MgF+ atoms 1 and 2

For MgF+ (magnesium fluoride cation)
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) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ
Moller Plesset perturbation MP2=FULL -0.0025 -0.0008 -0.0008 -0.0004 0.0064 0.0024 0.0036 0.0002 0.0002 0.0084 0.0021 0.0001 0.0044 0.0079 0.0049 0.0140 0.0170
MP3=FULL         0.0025   0.0033       0.0014 0.0002 0.0042        
MP4=FULL   -0.0008     0.0024       0.0002     0.0001 0.0047   0.0051 0.0153  
B2PLYP=FULL -0.0009 -0.0003 -0.0003 -0.0002 0.0008 0.0008 0.0010 -0.0000 -0.0000 0.0027 0.0004 0.0000 0.0013   0.0016 0.0042  
Quadratic configuration interaction QCISD(T)=FULL         0.0024             0.0001 0.0044   0.0050 0.0146  
Coupled Cluster CCSD=FULL         0.0025         0.0086 0.0013 0.0002 0.0043 0.0077 0.0050 0.0147 0.0169
CCSD(T)=FULL         0.0024           0.0012 0.0001 0.0043 0.0080 0.0050 0.0146 0.0172
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 cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ

mgfq1.gif