11. HOMO and LUMO are sometimes referred to as "'frontier orbitals "'in Frontier molecular orbital theory . 12. In consequence, molecular orbital theory was also referred to as the "'Hund-Mulliken theory . "' 13. The geometry can also be understood by molecular orbital theory where the electrons are delocalised. 14. Antibonding orbitals are also important for explaining chemical reactions in terms of molecular orbital theory . 15. Non-bonding orbitals are the equivalent in molecular orbital theory of the lone pairs in Lewis structures. 16. And yet what came to be known as his frontier-orbitals theory was little noticed at first. 17. This book is credited with causing the expansion of interest in molecular orbital theory from the 1950s. 18. According to molecular orbital theory , molecular orbitals are often modeled by the linear combination of atomic orbitals. 19. Hybridisation theory is an integral part of organic chemistry and in general discussed together with molecular orbital theory . 20. An analysis within quantitative molecular orbital theory shows that 2-orbital-4-electron ( steric ) repulsions are dominant over hyperconjugation.