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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 I2 atoms 1 and 2

For I2 (Iodine diatomic)
Bond length differences (full - frozen) in Å. Mouse over a difference for the bond length with full correlation.
Methods with standard basis sets
3-21G 3-21G* 6-311G*
Moller Plesset perturbation MP2=FULL -0.0008 0.0014 0.0185
Coupled Cluster CCSD(T)=FULL     -0.0025
3-21G 3-21G* 6-311G*

i2q1.gif