Vibrational Spectroscopy and Excited State Molecular Dynamics of Phenylene Ethynylene Polymers

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Material Information

Title:
Vibrational Spectroscopy and Excited State Molecular Dynamics of Phenylene Ethynylene Polymers
Physical Description:
1 online resource (114 p.)
Language:
english
Creator:
Galindo Cruz, Johan Fabian
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Chemistry
Committee Chair:
ROITBERG,ADRIAN E
Committee Co-Chair:
BOWERS,CLIFFORD RUSSELL
Committee Members:
KLEIMAN,VALERIA DANA
POLFER,NICOLAS CAMILLE
LONG,JOANNA R

Subjects

Subjects / Keywords:
dendrimers -- naesmd -- qmmm -- spectroscopy
Chemistry -- Dissertations, Academic -- UF
Genre:
Chemistry thesis, Ph.D.
Electronic Thesis or Dissertation
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )

Notes

Abstract:
Energy transfer is a vital process because of its critical role in photosynthesis as well as in the development of new technological devices such as biosensors, photovoltaics and light emitting devices. Dendrimeric polymers are one of the most explored light-harvesting molecules. The characterization of the excited statesof this group of molecules as well as the study of their energy transfer mechanism is an important step to gain further insight into this process and its application.For this purpose, we have studied a family of two and three ring linear poly(phenylene ethynylene) dendrimers which are either meta or ortho substituted. These dendrimers are able to mimic energy transfer that occurs in photosynthetic systems. We have performed IR spectroscopy calculations using linear response theory and analyzed the propagation of the ground state normal modes in the excited state. We identified a band at 2150 cm-1 that is characteristic of S1 in the meta- substituted molecule, for which S1 and S2 have transition densities localized over different regions of the molecule, while the ortho substituted case, the states are spread over the entire molecule. We find that the coupling between vibrations associated to C C triple bonds plays an important role in the nonadiabaticelectronic energy transfer. These results are a guide to the experimental characterization of specific electronic excited state vibrations of these molecules.Next, we proceed to study the larger 2G1m-Eper, a Poly(Phenylene Ethynylene) based molecule. We have used Nonadiabatic Excited State Molecular Dynamicsto study the energy transfer mechanism after an excitation at 400 nm. We have found that the initial excitation is delocalized between the two monodendrons, evolving to an intermediate state located in one of them. From this state, the system transitions to S1, localized in the perylene trap, and photon emission can takeplace to return to the ground state. These results are in good agreement with experimental information and will help researchers improve the design of newlight-harvesting molecules. Finally, we have developed new tools to simulate different vibrational spectroscopies that can be applied to dendrimer molecules as well as bio-systems. The calculation of vibrational spectra as a local property of a solute in its chemical environment provides results that are in good agreement with experimental data.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Thesis:
Thesis (Ph.D.)--University of Florida, 2014.
Local:
Adviser: ROITBERG,ADRIAN E.
Local:
Co-adviser: BOWERS,CLIFFORD RUSSELL.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2014-11-30
Statement of Responsibility:
by Johan Fabian Galindo Cruz.

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Embargo Date:
11/30/2014
Classification:
lcc - LD1780 2014
System ID:
UFE0046532:00001