Electric field induced activation of H2—Can DFT do the job?

The activation of dihydrogen by frustrated Lewis pairs (FLP) is initially driven by the electric field created inside a molecular cavity [Angew. Chem., Int. Ed., 2010, 49, 1402]. Here we test the accuracy of different density functional methods to describe H(2) dissociation in an external electric field in comparison to almost exact results. For larger field strengths (>0.06 a.u.), the dissociation mechanism changes from bi-radical like to zwitter-ionic.