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Measurements of Long-range Electronic Correlations During Femtosecond Diffraction Experiments Performed on Nanocrystals of Buckminsterfullerene
Published on: August 22, 2017
Estudio XANES de femtosegundos de la dinámica de cruce de espín inducido por la luz en un complejo de hierro (II)
Ch Bressler1, C Milne, V-T Pham
1Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, ISIC, FSB-BSP, CH-1015 Lausanne, Switzerland.
Science (New York, N.Y.)
|December 17, 2008
Resumen
La espectroscopia de absorción de rayos X ultrarrápida rastreó la formación del estado de quinteto en complejos de hierro (II) tris (bipiridina). Esto revela un mecanismo de cascada de 150 femtosegundos, aclarando la dinámica de la población del estado del quinteto.
Área de la Ciencia:
- Física Química Física Química es la física de la química.
- La fotoquímica es la fotoquímica.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- La espectroscopia de absorción de rayos X (XAS, por sus siglas en inglés) analiza la estructura molecular.
- Los métodos XAS anteriores eran demasiado lentos para dinámicas ultrarrápidas.
- Los complejos de hierro (II) exhiben un comportamiento complejo de estado excitado.
Objetivo del estudio:
- Investigar la formación del estado de quinteto ultrarrápido en el hierro acuoso (II) tris (II) bipiridina).
- Determine la escala de tiempo de la población del estado del quinteto después de la fotoexcitación.
- Aclarar el mecanismo de la formación del estado de quinteto en complejos de hierro.
Principales métodos:
- La bomba óptica de femtosegundos y la espectroscopia de la sonda de rayos X.
- Análisis de la estructura de absorción de rayos X cercana al borde (XANES). análisis.
- Monitoreo de las características de XANES con retrasos en el tiempo.
Principales resultados:
- El estado del quinteto se pobló en aproximadamente 150 femtosegundos.
- Todo el espectro XANES del estado del quinteto registrado a 300 fs.
- Se identificó un mecanismo en cascada de 1MLCT → 3MLCT → 5T.
Conclusiones:
- Resolvió la cuestión de larga data de los mecanismos de población del quinteto de estados.
- Demostró la capacidad de XAS para rastrear dinámicas ultrarrápidas.
- Relajación 3MLCT → 5T vinculada a los períodos de vibración Fe-N.
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