Experimental estimates of photolytic efficiency (yield per photon) for photodissociation and photodesorption from water ice range from about 10(-3) to 10(-1). However, in the case of photodissociation of water in the gas phase, it is close to unity. Exciton dynamics carried out by a quantum mechanical time-dependent propagator shows that in the eight most stable water hexamers, the excitation diffuses away from the initially excited molecule within a few femtoseconds. On the basis of these quantum dynamics simulations, it is hypothesized that the ultrafast exciton energy transfer process, which in general gives rise to a delocalized exciton within these clusters, may contribute to the low efficiency of photolytic processes in water ice. It is proposed that exciton diffusion inherently competes with the nuclear dynamics that drives the photodissociation process in the repulsive S-1 state on the sub-10 fs time scale.

Acocella A., Jones G.A., Zerbetto F. (2012). Excitation Energy Transfer and Low-Efficiency Photolytic Splitting of Water Ice by Vacuum UV Light. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 3, 3610-3615 [10.1021/jz301640h].

Excitation Energy Transfer and Low-Efficiency Photolytic Splitting of Water Ice by Vacuum UV Light

ACOCELLA, ANGELA;ZERBETTO, FRANCESCO
2012

Abstract

Experimental estimates of photolytic efficiency (yield per photon) for photodissociation and photodesorption from water ice range from about 10(-3) to 10(-1). However, in the case of photodissociation of water in the gas phase, it is close to unity. Exciton dynamics carried out by a quantum mechanical time-dependent propagator shows that in the eight most stable water hexamers, the excitation diffuses away from the initially excited molecule within a few femtoseconds. On the basis of these quantum dynamics simulations, it is hypothesized that the ultrafast exciton energy transfer process, which in general gives rise to a delocalized exciton within these clusters, may contribute to the low efficiency of photolytic processes in water ice. It is proposed that exciton diffusion inherently competes with the nuclear dynamics that drives the photodissociation process in the repulsive S-1 state on the sub-10 fs time scale.
2012
Acocella A., Jones G.A., Zerbetto F. (2012). Excitation Energy Transfer and Low-Efficiency Photolytic Splitting of Water Ice by Vacuum UV Light. THE JOURNAL OF PHYSICAL CHEMISTRY LETTERS, 3, 3610-3615 [10.1021/jz301640h].
Acocella A.; Jones G.A.; Zerbetto F.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/134711
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