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Compresión de hielo a 210 gigapascales: evidencia infrarroja de una fase simétrica de enlace con hidrógeno
Goncharov1, Struzhkin, Somayazulu
1Geophysical Laboratory and Center for High Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015, USA.
Science (New York, N.Y.)
|July 12, 1996
Resumen
Los experimentos de alta presión revelan una transición de fase en el hielo de agua (H2O) y el hielo de agua pesada (D2O) a presiones extremas. Esta transición sugiere una transformación a una estructura con enlaces simétricos de hidrógeno, observada a través de la espectroscopia infrarroja.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Física de la materia condensada Física de la materia condensada
- Ciencias planetarias Ciencias planetarias.
Sus antecedentes:
- El hielo de agua (H2O) y el hielo de agua pesada (D2O) son componentes cruciales en la ciencia planetaria.
- Comprender las fases de hielo bajo presión extrema es vital para modelar los interiores planetarios.
Objetivo del estudio:
- Para investigar el comportamiento de fase de los hielos protonados y deuterados bajo alta presión.
- Para caracterizar los cambios estructurales que ocurren durante la compresión utilizando métodos espectroscópicos.
Principales métodos:
- La compresión de H2O y D2O baja a 210 GPa a temperaturas entre 85-300 K.
- Espectroscopia de reflectancia infrarroja utilizando radiación sincrotrón para analizar los cambios espectrales.
- Análisis del comportamiento del modo blando y los cambios espectrales inducidos por la presión.
Principales resultados:
- Se observó una transición de fase en hielo H2O a 60 GPa y en hielo D2O a 70 GPa.
- La transición involucró el comportamiento de modo blando del tramo nu3 O-H/O-D por debajo de la presión de transición, seguido de endurecimiento por encima de ella.
- Las características espectroscópicas indicaron una transformación a una estructura con enlaces de hidrógeno simétricos, que persiste hasta 210 GPa.
Conclusiones:
- El estudio proporciona evidencia de una nueva fase de hielo de alta presión con enlaces simétricos de hidrógeno.
- Este hallazgo tiene implicaciones para la comprensión de la composición y estructura de los cuerpos helados en el sistema solar.
- Los cambios en el acoplamiento del modo vibratorio a 150-160 GPa sugieren complejidades estructurales adicionales a presiones extremas.
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