Probably a couple points to note -this is intramolecular singlet fission within the H4 molecule. -The energy requirement (especially for intermolecular single

Probably a couple points to note -this is intramolecular singlet fission within the H4 molecule. -The energy requirement (especially for intermolecular singlet fission) can be theoretically derived from the massive Thirring model assuming some degree of strong electron correlation.