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Coupled cluster calculations provide a one‐to‐one mapping between calculated and observed transition energies in the electronic absorption spectrum of zinc phthalocyanine
Author(s) -
Wallace Andrew J.,
Williamson Bryce E.,
Crittenden Deborah L.
Publication year - 2017
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25350
Subject(s) - homo/lumo , excited state , atomic orbital , chemistry , molecular orbital , rydberg formula , oscillator strength , absorption spectroscopy , atomic physics , molecular electronic transition , atomic electron transition , absorption (acoustics) , molecular physics , physics , spectral line , molecule , electron , optics , quantum mechanics , ion , organic chemistry , ionization
All transitions in the experimentally designated and numbered Q, B, and N bands (< 4.8 eV) of the electronic absorption spectrum of zinc phthalocyanine (ZnPc) are assigned on the basis of one‐to‐one agreement between calculated and experimentally observed transition energies and oscillator strengths. Each band in this range of the spectrum represents a ligand‐based transition that originates from a combination of occupied orbitals and terminates in the lowest unoccupied molecular orbital (LUMO, 6 e g ( π ) ). Transition energies in the L and C regions (4.8–6.5 eV) are harder to capture quantitatively, due to the partial Rydberg character of some of the excited states, and so are tentatively assigned here. Most transitions in this range correspond to excitations from the HOMO or lower‐energy orbitals to π orbitals above the LUMO.