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Dinámica de separación y conversión de cuatro isómeros nucleares de espín de etileno
Zhen-Dong Sun1, Kojiro Takagi, Fusakazu Matsushima
1Department of Physics, University of Toyama, Toyama 930-8555, Japan. zdsun@unbsj.ca
Science (New York, N.Y.)
|December 24, 2005
Resumen
Los investigadores estudiaron la interconversión del isómero de espín nuclear en el gas etileno. Descubrieron que el isómero B2u se convierte en el isómero B3u a una velocidad dependiente de la presión, lo que sugiere un mecanismo de relajación cuántica.
Área de la Ciencia:
- Química Física es la química física.
- Espectroscopia molecular Espectroscopia molecular es la espectroscopia molecular.
- La mecánica cuántica es la mecánica cuántica.
Sus antecedentes:
- Las moléculas con múltiples núcleos de espín distintos de cero existen como isómeros de espín discretos.
- La interconversión entre estos isómeros de espín en la fase gaseosa es típicamente improbable.
- Comprender la dinámica de los isómeros de espín es crucial para los estudios de comportamiento molecular.
Objetivo del estudio:
- Para investigar el proceso de interconversión de los isómeros de espín nuclear en etileno (C2H4).
- Para determinar la velocidad y el mecanismo de conversión del isómero de espín en el gas etileno.
- Para explorar la influencia de la relajación cuántica en la dinámica del isómero de espín.
Principales métodos:
- Creación de una muestra de etileno empobrecido en el isómero de espín nuclear B2u.
- Separación espacial del isómero B2u utilizando la absorción de luz infrarroja resonante.
- Monitorear la evolución de las poblaciones de isómeros a lo largo del tiempo a diferentes presiones.
Principales resultados:
- Se logró el agotamiento del isómero de espín nuclear B2u en etileno.
- Se observa la conversión entre los isómeros B2u y B3u a una velocidad linealmente proporcional a la presión.
- Se ha determinado una constante de velocidad de 5,5 (+/-0,8) x 10(-4) s(-1) torr(-1) para la conversión B2u-B3u.
- Se encontró una interconversión insignificante que involucra al isómero Ag.
Conclusiones:
- El estudio demuestra que la interconversión de isómeros de espín en etileno es alcanzable.
- Los resultados sugieren un mecanismo de conversión de espín en C2H4 que implica relajación cuántica dentro de la misma simetría de inversión.
- Los hallazgos proporcionan información sobre la dinámica molecular de la fase gaseosa y el isomerismo de espín.
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