Energy migration in the aromatic vinyl polymers. 5. Poly(2-vinyl naphthalene) and polystyrene

1985 ◽  
Vol 63 (6) ◽  
pp. 1328-1332 ◽  
Author(s):  
Steven N. Semerak ◽  
Curtis W. Frank
Keyword(s):  
Nearest Neighbor ◽  
Transport Model ◽  
Homogeneous System ◽  
Electronic Energy ◽  
Energy Migration ◽  
Periodic Lattice ◽  
Single Chain ◽  
Vinyl Polymers ◽  
Chain Fraction ◽  
Ring Pair

Electronic energy migration in pure poly(2-vinyl naphthalene) (P2VN) is analyzed in terms of a theory for three-dimensional transport and trapping in a homogeneous system of randomly distributed chromophores. A simpler theory for 3-D transport on a spatially periodic lattice, which was applied previously to polystyrene (PS) gave self-contradictory results for P2VN because of higher transport rates in P2VN. The fraction of rings in excimer-forming sites (EFS) in pure P2VN, analyzed by the former theory, is found to be 0.072 – moderately larger than the single-chain fraction of 0.026. In contrast, the EFS ring fraction in pure PS was 0.33, much larger than the single-chain fraction of 0.051. This reflects the reduced probability, relative to a phenyl ring pair, of packing a naphthyl ring pair into the necessary sandwich arrangement in the pure polymers. Energy migration in very dilute, miscible blends containing P2VN is analyzed by a one-dimensional transport model, which was applied previously to similar blends containing PS. The nearest-neighbor migration rates obtained from the data for both P2VN and PS are about one hundred times higher than the expected dipole–dipole rates. This suggests that (1) migration is not limited to nearest-neighbor rings, (2) the morphology of the dilute blends does not consist of isolated chains of the aromatic vinyl polymers, or (3) short-range electronic interactions other than dipole–dipole are involved in energy migration.

On the analyses of fluorescence depolarisation data in the presence of electronic energy migration. Part II: Applying and evaluating two-photon excited fluorescence

2012 ◽  
Vol 14 (6) ◽  
pp. 1917
Author(s):  
Oleg Opanasyuk ◽  
Therese Mikaelsson ◽  
Linus Ryderfors ◽  
Emad Mukhtar ◽  
Lennart B.-Å. Johansson
Keyword(s):  
Electronic Energy ◽  
Energy Migration ◽  
Two Photon

Two-photon excited fluorescence depolarisation and electronic energy migration within donor–donor pairs

2009 ◽  
Vol 11 (33) ◽  
pp. 7152 ◽  
Author(s):  
Oleg Opanasyuk ◽  
Linus Ryderfors ◽  
Emad Mukhtar ◽  
Lennart B.-Å. Johansson
Keyword(s):  
Electronic Energy ◽  
Energy Migration ◽  
Two Photon

Electronic Energy Migration (or Hopping)

2016 ◽  
Author(s):  
Silvia E. Braslavsky ◽  
André M. Braun ◽  
Alberto E. Cassano ◽  
Alexei V. Emeline ◽  
Marta I. Litter ◽  
...  
Keyword(s):  
Electronic Energy ◽  
Energy Migration

Validation of an Enhanced Dispersion Algorithm for Use With the Statistical Phonon Transport Model

2020 ◽  
Author(s):  
Michael P. Medlar ◽  
Edward C. Hensel
Keyword(s):  
Computer Simulations ◽  
Wave Vector ◽  
Lattice Dynamics ◽  
Nearest Neighbor ◽  
Transport Model ◽  
Phonon Transport ◽  
Dispersion Relations ◽  
High Fidelity ◽  
High Symmetry ◽  
Energy And Momentum

Abstract Computer simulations of quasi-particle based phonon transport in semiconductor materials rely upon numerical dispersion relations to identify and quantify the discrete energy and momentum states allowable subject to quantum constraints. The accuracy of such computer simulations is ultimately dependent upon the fidelity of the underlying dispersion relations. Dispersion relations have previously been computed using empirical fits of experimental data in high symmetry directions, lattice dynamics, and Density Function Theory (DFT) or Density Functional Perturbation Theory (DFPT) approaches. The current work presents high fidelity dispersion relations describing full anisotropy for all six phonon polarizations with an adjustable computational grid. The current approach builds upon the previously published Statistical Phonon Transport Model (SPTM), which employed a first nearest neighbor lattice dynamics approach for the dispersion calculation. This paper extends the lattice dynamics approach with the use of both first and second nearest neighbors interactions that are quantified using published interatomic force constants calculated from DFT. The First Brillouin Zone (FBZ) is segmented into eight octants of high symmetry, and discretized in wave vector space with a 14 by 14 by 14 grid. This results in 65,586 states of unique wave vector and frequency combinations. Dispersion calculations are performed at each of the six faces of the wave vector space volume elements in addition to the centroid, resulting in 460,992 solutions of the characteristic equations. For the given grid, on the order of 108 computations are required to compute the dispersion relations. The dispersion relations thus obtained are compared to experimental reports available for high symmetry axes. Full anisotropic results are presented for all six phonon polarizations across the range of allowable wave vector magnitude and frequency as a comprehensive model of allowable momentum and energy states. Results indicate excellent agreement to experiment in high symmetry directions for all six polarizations and illustrate an improvement as compared to the previous SPTM implementation. Dispersion relations based on the lattice dynamic model with first and second nearest neighbor atomic interactions relying upon DFT calculated inter-atomic force constants provides an accurate high fidelity energy and momentum model for use in phonon transport simulations.

Studies of the electronic energy migration and trapping in styrene copolymers

1985 ◽  
Vol 18 (12) ◽  
pp. 2714-2719 ◽  
Author(s):  
K. Sienicki ◽  
C. Bojarski
Keyword(s):  
Electronic Energy ◽  
Energy Migration ◽  
Styrene Copolymers

Energy migration in the aromatic vinyl polymers. 1. A one-dimensional random walk model

1982 ◽  
Vol 15 (3) ◽  
pp. 733-741 ◽  
Author(s):  
Patrick D. Fitzgibbon ◽  
Curtis W. Frank
Keyword(s):  
Random Walk ◽  
Energy Migration ◽  
Random Walk Model ◽  
One Dimensional ◽  
Vinyl Polymers
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