514360 EHOMO energy of the highest occupied molecular orbital 25 514357 EHOMO DFT-derived highest occupied molecular orbital energies 2 514358 EHOMO exhibited that the down-shifted highest occupied molecular orbital energy level 2 514362 EHOMO HOMO energy 2 514363 EHOMO downshifted highest occupied molecular orbital energy level 1 514361 EHOMO energies of the HOMO 1 514359 EHOMO exhibited a deeper highest occupied molecular orbital level 1