Now showing items 121-130 of 140
Comment: phonon spectrum of molecular crystals from exciton sidebands
(Elsevier, 1974-11-01)
Phonon sidebands of excitons in molecular crystals with negligibly small excitation exchange interactions, including isotopic guest systems, are not, in general, expected to be predominantly weighted by translational modes ...
Low-temperature calorimetry — quo vadis?
(Kluwer Academic Publishers; Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest ; Springer Science+Business Media, 1978-10)
Experimental progress in adiabatic, cryogenic calorimetry is tersely reviewed and contrasted with other techniques for heat capacity determinations in this temperature region—including DSC. Trends and prognostications of ...
Exciton Superexchange, Resonance Pairs, and Complete Exciton Band Structure of 1B2u1B2u Naphthalene
(The American Institute of Physics, 1971-07-15)
A method for the determination of complete exciton band structures in molecular crystals is given. Pairwise exciton interactions are derived from resonance‐pair data using an exciton “superexchange” approach. Koster and ...
Raman Phonon Spectra of Isotopic Mixed Naphthalene Crystals: Librational Exciton Model and the Amalgamation Limit
(The American Institute of Physics, 1972-07-15)
We present an experimental Raman study of lattice modes in neat and mixed (10%–90%) crystals of naphthalene‐h8 and naphthalene‐d8 at 100°K with 1 cm−1 resolution. The spectral features of the neat crystals are preserved ...
Time resolved exciton migration in mixed naphthalene crystals: triplet and singlet critical concentrations
(Elsevier, 1979-06-15)
The contrasting temporal characteristics of the triple and singlet transport (below 4 K) correlate with dynamic and quasistatic percolation, respectively. They do not support an Anderson--Mott transition (AMT) for the ...
Random Lattice Calculations on Frenkel Excitons in Disordered Molecular Crystals—1B2u Naphthalene
(The American Institute of Physics, 1971-12-01)
Using the recently acquired exciton dispersion relations for crystalline naphthalene, we have calculated the density‐of‐states functions for heavily doped isotopic binary mixed crystals of naphthalenes with arbitrary ...
Quantitative tests of mixed crystal exciton theory. II. Energy denominator study of naphthalene 1B2u resonance pairs
(The American Institute of Physics, 1977-02-15)
A spectroscopic absorption study is presented of 1‐D1C10H7, 2‐D1C10H7, and 1,4‐D2C10H7 resonance pairs in C10D8, over a concentration range of 0.009% to 5% mole, at 2 °K, with a resolution of 0.5 cm−1. The resulting structure ...