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Coupling of charge‐transfer transitions to low‐wavenumber phonons in quasi‐one‐dimensional radical ion salts: resonance Raman study of tetraethylammonium‐DDQ
Author(s) -
Pedron D.,
Lavina S.,
Mulloni V.,
Bozio R.
Publication year - 1998
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(199810/11)29:10/11<907::aid-jrs327>3.0.co;2-l
Subject(s) - raman spectroscopy , chemistry , resonance (particle physics) , excitation , phonon , molecular physics , ion , wavenumber , electron paramagnetic resonance , electron transfer , atomic physics , nuclear magnetic resonance , condensed matter physics , photochemistry , physics , optics , organic chemistry , quantum mechanics
Low‐wavenumber resonance Raman spectra of the quasi‐1‐D anionradical salt tetratethylammoniumdichlorodicyano‐ p ‐benzoquinoneare reported. By investigating the resonance behavior of the observedbands when the excitation wavelength is tuned from resonance with alocalized electronic transition at 530 nm to the charge‐transfertransition at 761 nm, three phonon modes at 148, 173, and 194cm ‐1 coupled with the radical electrons through themodulation of their transfer integral are unambiguously identified.The Raman excitation profiles for these modes, measured in the650–860 nm excitation wavelength range, were analyzed accordingto a Peierls–Hubbard dimer Hamiltonian using a time correlatorapproach. By combining the analysis of the excitation profiles withthat of previously reported magnetic susceptibility data, it ispossible to obtain values for the transfer integral, for the on‐siteelectron correlation and for the electron–phonon couplingconstants. © 1998 John Wiley & Sons, Ltd.