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Observaciones visuales de la transición amorfo-amorfo en H2O bajo presión
Science (New York, N.Y.)
|October 18, 1991
Resumen
Los investigadores comprimieron agua amorfa de baja densidad (H2O) y observaron una transición distinta y reversible a una fase amorfa de alta densidad. Este hallazgo proporciona evidencia experimental para el polimorfismo en agua amorfa.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Física es la química física.
- La geofísica es la geofísica.
Sus antecedentes:
- El agua sólida amorfa (ASW) existe en varias formas, incluidas las fases amorfas de baja densidad (LDA) y alta densidad (HDA).
- Comprender las transiciones de fase entre estos estados amorfos es crucial para la ciencia planetaria y la investigación de materiales.
Objetivo del estudio:
- Investigar experimentalmente el límite de fase y el mecanismo de transición entre LDA y HDA.
- Para proporcionar evidencia de polimorfismo en el H2O amorfo.
Principales métodos:
- Compresión directa de LDA H2O depositado en vapor a 77 K utilizando una célula de yunque de diamante.
- Observación in situ de la transición de LDA a HDA durante el calentamiento bajo compresión.
Principales resultados:
- Se observó que la transición de LDA a HDA es distinta y reversible.
- Esta transición ocurrió dentro de un estrecho rango de presión entre aproximadamente 130 K y 150 K.
Conclusiones:
- La transición reversible observada proporciona evidencia experimental directa para el polimorfismo en el H2O amorfo.
- Este estudio aclara el comportamiento de fase del agua amorfa bajo variaciones de presión y temperatura.
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