We find, by means of a deep inelastic neutron scattering experiment, a significant excess of proton mean kinetic energy < E(k)> in supercooled water, compared with that measured in stable liquid and solid phases. The measured values of < E(k)> at moderate degrees of supercooling do not fit the predicted linear increase with temperature observed for the water stable phases. This anomalous behavior is confirmed by the shape of the measured momentum distribution, thus supporting a likely occurrence of ground-state quantum delocalization of a proton between the O atoms of two neighboring molecules. These results strongly suggest a transition from a single-well to a double-well potential felt by the delocalized proton, with a reduced first neighbor O-O distance, in the supercooled state, as compared to ambient condition.

Pietropaolo, A., Senesi, R., Andreani, C., Botti, A., Ricci, M., Bruni, F. (2008). Excess of proton mean kinetic energy in supercooled water. PHYSICAL REVIEW LETTERS, 100(12) [10.1103/PhysRevLett.100.127802].

Excess of proton mean kinetic energy in supercooled water

PIETROPAOLO, ANTONINO;SENESI, ROBERTO;ANDREANI, CARLA;
2008-01-01

Abstract

We find, by means of a deep inelastic neutron scattering experiment, a significant excess of proton mean kinetic energy < E(k)> in supercooled water, compared with that measured in stable liquid and solid phases. The measured values of < E(k)> at moderate degrees of supercooling do not fit the predicted linear increase with temperature observed for the water stable phases. This anomalous behavior is confirmed by the shape of the measured momentum distribution, thus supporting a likely occurrence of ground-state quantum delocalization of a proton between the O atoms of two neighboring molecules. These results strongly suggest a transition from a single-well to a double-well potential felt by the delocalized proton, with a reduced first neighbor O-O distance, in the supercooled state, as compared to ambient condition.
2008
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/03 - FISICA DELLA MATERIA
English
Con Impact Factor ISI
Pietropaolo, A., Senesi, R., Andreani, C., Botti, A., Ricci, M., Bruni, F. (2008). Excess of proton mean kinetic energy in supercooled water. PHYSICAL REVIEW LETTERS, 100(12) [10.1103/PhysRevLett.100.127802].
Pietropaolo, A; Senesi, R; Andreani, C; Botti, A; Ricci, M; Bruni, F
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/31149
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