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Ultrafast electronic population decay

The SHG intensity from interfaces is determined by the second-order nonlinear susceptibility and the Fresnel coefficients. The SHG spectra of the probe pulses change depending on the transient electronic population and the orientation of the chromophores through these physical quantities. Hohlfeld and coworkers have studied hot electron dynamics in thin metal films by this technique [21]. From the transient response of the SHG intensity, electronic temperature decay due to the electron-phonon coupling in the metal substrate is extracted. Eisenthal and coworkers have studied ultrafast excited state dynamics of dye molecules at liquid interfaces [22]. Particularly, the isomerization dynamics of an organic dye at the interfaces was found to become significantly slower than in the bulk. [Pg.58]

This deuterium isotope effect cannot be explained by a purely electronic process but could be explained by a proton-coupled electron transfer. The population decay rate of the excited state at a fixed energy is successfully decomposed into two components an isotope independent solvation term and a proton-coupled electron transfer term with a marked deuterium effect. The latter terms for the CH3OH overlayer are found to be about twice those for the CH3OD overlayer. Thus, with time-resolved 2PPE, the ultrafast dielectric response of a protic/solvent metal-oxide interface has been revealed. [Pg.63]

Ultrafast Photodissociation. Since radiative decay of the trimer is in the time domain of nanoseconds, this population can be changed either by photodissociation or by intersystem crossing to an electronic state, from which, under these experimental conditions, no ionization can take place. However, in the latter case this behavior should be directly visible as a drastic modulation of the observed wave packet propagation [43, 329, 315]. But this is not found. Apart from this, the first theoretical calculations of the PES of Ka gave no evidence of the existence of any dark state in this energy regime. Therefore, it seems to be reasonable that ultrafast photodissociation causes the fast decay of the ion signal. The K2 can also be ionized by the probe pulse. [Pg.123]


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See also in sourсe #XX -- [ Pg.461 ]




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Electron population

Electronic populations

Population decay

Ultrafast

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