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Regulación del tiempo de vida en estado excitado de una sola molécula en femtosegundos

K R Rusimova¹, R M Purkiss¹, R Howes¹

¹Department of Physics, University of Bath, Bath BA2 7AY, UK.

Science (New York, N.Y.)

|September 8, 2018

Resumen

El control de las reacciones moleculares con un microscopio de túnel de exploración (STM) implica la gestión de los estados iónicos excitados. La precisión de la proximidad de la punta altera dramáticamente el estado excitado

Área de la Ciencia:

Ciencias de la superficie
Dinámica molecular
Microscopía de túnel de exploración

Sus antecedentes:

El control de las reacciones moleculares es crucial en química y ciencias de los materiales.
La microscopía de túnel de barrido (STM) ofrece capacidades de manipulación a escala atómica.
Comprender la dinámica del estado excitado es clave para el control de la reacción.

Objetivo del estudio:

Investigar cómo la proximidad de la punta del STM influye en la dinámica del estado excitado.
Demostrar una influencia directa y controlable sobre las reacciones moleculares a través del STM.
Para elucidar el mecanismo de desorción inducida por STM de tolueno de Si{11}-7x7.

Principales métodos:

Utilizando microscopía de túnel de barrido (STM) para la manipulación molecular.
Monitoreo in situ de la desorción del tolueno inducida por el STM.
Analizando la dependencia de la probabilidad de reacción en la altura de la punta.

Principales resultados:

La proximidad de la punta del STM tiene un impacto significativo en la dinámica del estado excitado.
Se observó una caída de dos órdenes de magnitud en la probabilidad de manipulación a medida que la punta se acercaba a la molécula.
Se propuso un modelo de apagado de dos canales (dependiente de la superficie y de la punta) para explicar la dinámica.

Conclusiones:

La proximidad de la punta del picómetro es crítica para regular las vidas de estado excitado.
Las vidas en estado excitado pueden ajustarse de femtosegundos a sub-femtosegundos.
El STM ofrece una poderosa herramienta para el control preciso de las reacciones moleculares a nanoescala.

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