Electronic mechanisms of molecular oxygen activation

Theoretical views on the mechanisms of overcoming spin prohibitions in photoprocesses and in enzymatic activation of the O₂ molecule are considered. The electronic structures of various quantum states of this molecule and collision complexes of oxygen with other molecules are given. The patterns of biochemical activation of O₂ through T–S transitions in enzymatic complexes are proposed. It is noted that the enhancement mechanisms for specific exchange interactions in enzymatic complexes have common features with mechanisms of physical photoactivation of oxygen.