The Geometry of FOOF

The cause of the problems with FOOF are harder to explain, but fluorine is known to be a somewhat troublesome element [126], although some fluoro organics apparently give good geometries at moderate computational levels [127]. 

The O3 geometry is now on the verge of satisfying ours accurate requirement, but the FOOF geometry still has unsatisfactory bond lengths. CCSD(T) with a considerably bigger basis set (similar to 6-311 (2d)) has been reported [92] to give for FOOF errors of... 

Kraka E, He Y, Cremer D (2001) Quanmm chemical descriptions of FOOF the unsolved problem of predicting its equilibrium geometry. J Phys Chem A105 3269-3276... 

The FOOF molecule has an experimental geometry with an 0-0 bond length of 1.217 A and a F-O bond length of 1.575 A. The calculated bond distances at different levels of... 

These calculated geometries do not satisfy even our fairly good criterion and are well short of being accurate the bond lengths are particularly bad. Using the 6-311-i-i-G basis (for FOOF, 88 vs. 60 basis functions for O3, 66 vs. 45 basis functions) we get for calculated geometries (errors) using HF/6-311 + -i-G ... 

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