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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 BeC atoms 1 and 2

For BeC (Beryllium Carbide)
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 0.0002 0.0004 0.0004 0.0005   0.0027 0.0029   0.0028 0.0097 0.0011 0.0020 0.0123 0.0087 0.0060 0.0180 0.0084
MP3=FULL         0.0026   0.0034       0.0010 0.0019 0.0194        
MP4=FULL   0.0004     0.0030       0.0027     0.0019 0.0200   0.0061 0.0198  
B2PLYP=FULL 0.0001 0.0001 0.0001 0.0001 0.0009 0.0009 0.0009 0.0009 0.0009 0.0029 0.0003 0.0006 0.0054   0.0019 0.0055  
Quadratic configuration interaction QCISD(T)=FULL         0.0028             0.0019 0.0200   0.0061 0.0203  
Coupled Cluster CCSD=FULL         0.0026           0.0010 0.0019 0.0197 0.0088 0.0060 0.0196 0.0086
CCSD(T)=FULL         0.0028           0.0010 0.0019 0.0203 0.0092 0.0061 0.0207 0.0091
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

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