Non-radiative relaxation of photoexcited chlorophylls: Theoretical and experimental study

 

Autores
Bricker, William P.; Shenai, Prathamesh M.; Ghosh, Avishek; Liu, Zhengtang; Enriquez, Miriam Grace M.; Lambrev, Petar H.; Tan, Howe-Siang; Lo, Cynthia S.; Tretiak, Sergei; Fernández Alberti, Sebastián; Zhao, Yang
Tipo de recurso
artículo
Estado
Versión publicada
Año de publicación
2015
País
Argentina
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
Repositorio
CONICET Digital (CONICET)
Descripción
Nonradiative relaxation of high-energy excited states to the lowest excited state in chlorophylls marks the first step in the process of photosynthesis. We perform ultrafast transient absorption spectroscopy measurements, that reveal this internal conversion dynamics to be slightly slower in chlorophyll B than in chlorophyll A. Modeling this process with non -Adiabatic excited state molecular dynamics simulations uncovers a critical role played by the different side groups in the two molecules in governing the intramolecular redistribution of excited state wavefunction, leading, in turn, to different time-scales. Even given smaller electron-vibrational couplings compared to common organic conjugated chromophores, these molecules are able to efficiently dissipate about 1 eV of electronic energy into heat on the timescale of around 200 fs. This is achieved via selective participation of specific atomic groups and complex global migration of the wavefunction from the outer to inner ring, which may have important implications for biological light-harvesting function.
Idioma
inglés
OAI Identifier
oai:ri.conicet.gov.ar:11336/59282
Enlace del recurso
http://hdl.handle.net/11336/59282
Nivel de acceso
Acceso abierto
Materia
Chlorophylls
Internal conversion
Non-adiabatic molecular dynamics
Excited states
Otras Ciencias Químicas
Ciencias Químicas
CIENCIAS NATURALES Y EXACTAS