Is hyper-hardness more chemically relevant than expected?

摘要: In this work, the third derivative of energy with respect to number electrons, so-called hyper-hardness, is investigated assess whether quantity has a chemical meaning. To achieve goal new working expression for hyper-hardness developed and analyzed. It transpired from analysis that just like hardness, can measure reactivity or stability electron systems. Interestingly, positive values point quite stable species such as noble gases molecules. On other hand, radicals almost always display large negative hyper-hardness.