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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 HI atoms 1 and 2

For HI (Hydrogen iodide)
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* 6-311G**
Moller Plesset perturbation MP2=FULL -0.0001 -0.0003 0.0092 -0.0013
3-21G 3-21G* 6-311G* 6-311G**