1,721,059 research outputs found
Effects of the mixing of charge transfer and molecular excitations on the resonance Raman properties of symmetric radical dimers
No full textThe mixing of charge transfer (CT) and molecular excitation (ME) states in a molecular radical dimer is investigated based on a model Hamiltonian for a dimer with two orbitals per site filled with two electrons. The CT/ME mixing brings about an intensity enhancement of intramolecular modes in the Raman spectra resonant with the CT absorption. The relevant parameter for this effect is the transfer integral tab for the hopping of one electron from orbital a in one molecule to orbital b in the other. This theoretical prediction is confirmed by Raman excitation profiles measured for the cation radical salt (TTF)2(W6O19)
Correlation between infrared spectra and magnetic and optical properties of potassium chloranil. Effects of phase transition and solvation processes
No full textVibrational analysis of spectra of quinonoid molecular ions. Part 3.?Vibrational spectra and assignment of 7,7,8,8-tetracyanoquinodimethane radical anion
No full textRaman and infrared studies of quasi one-dimensional organic conductors and semiconductors
No full textCoupling of charge-transfer transitions to low-wavenumber phonons in quasi-one-dimensional radical ion salts: resonance Raman study of tetraethylammonium-DDQ
No full textLow-wavenumber resonance Raman spectra of the quasi-1-D anion radical salt tetratethylammoniumdichlorodicyano-p-benzoquinone are reported. By investigating the resonance behavior of the observed bands when the excitation wavelength is tuned from resonance with a localized electronic transition at 530 nm to the charge-transfer transition at 761 nm, three phonon modes at 148, 173, and 194 cm-1 coupled with the radical electrons through the modulation of their transfer integral are unambiguously identified. The Raman excitation profiles for these modes, measured in the 650–860 nm excitation wavelength range, were analyzed according to a Peierls–Hubbard dimer Hamiltonian using a time correlator approach. By combining the analysis of the excitation profiles with that of previously reported magnetic susceptibility data, it is possible to obtain values for the transfer integral, for the on-site electron correlation and for the electron–phonon coupling constants
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Infrared and Raman spectroscopic evidence of ground state charge densities at TCNQ sites in crystalline Cs2 (TCNQ)3
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