Magnetic and optical properties of exact PPP states of naphthalene
1984; Elsevier BV; Volume: 91; Issue: 1 Linguagem: Inglês
10.1016/0301-0104(84)80040-3
ISSN1873-4421
Autores Tópico(s)Advanced NMR Techniques and Applications
ResumoThe Pariser—Parr—Pople (PPP) hamiltonian for naphthalene is solve exactly, to all orders in configuration interaction, using diagrammatic (VB) theory. Standard molecular parameters place the 3B2u, 1B2u, and 1B2a excitations within 0.3 eV of experiment. VB methods for correlated states are extended to the fine-structure constants D and E of the triplet state, which are found to be better than 0.01 cm−1 without any adjustable parameters. Negative spin densities are found at the 9.10 carbons. The weak (f = 0.0005) oscillator strength of the 1B2u transition is related to the absence of electron—hole symmetry on introducing different ionization potential at the 9.10 carbons. The static spin-correlation functions needed for D and E extend the accessible matrix elements over correlated states based on linear combinations of VB diagrams for model hamiltonians with one valence state per site.
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