Ground state heterogeneity

The best tool for observation of these phenomena is time-resolved spectroscopy [42, 43] that makes it possible to observe the excitation-wavelength-dependent evolution of the spectra in time. The steady-state observations can be complicated by the existence of ground-state heterogeneity [44] that originates not only from the presence of different dyes but also from the same dyes participating in different (e.g., H-bonding) interactions. 

Figure 2.21 Schematics illustrating photosensitized heterogeneous electron transfer mechanisms (a) a directly bound photosensitizer, which photoinjects directly to the electrode (b) a remotely bound bridge sensitizer, which undergoes a prior photoinduced electron transfer, followed by ground-state heterogeneous electron transfer to the electrode...

Recent Experimental Approaches Our most recent attempt to investigate the problem of ground-state heterogeneity experimentally uses tunable pump laser pulses derived from a home-made optical parametric amplifier (Fig. 1.9). A white light continuum is used to seed a two-stage optical parametric amplifier pumped by the second harmonic of a regeneratively amplified Ti-sapphire laser... 

A ground-state heterogeneity resulting from the presence of equilibrium between different conformers. Each conformer presents a specific fluorescence lifetime. 

Generally the REE occurs when a ground state heterogeneity exists and the excited state relaxation is slow [15]. In the case of ionic liquids their generally high viscosities and short fluorescence lifetimes favour this effect. 

Global and target analysis of complex decay phenomena and the examination of ground state heterogeneity, anisotropic motions, and excited state reactions has been critically reviewed and a method... 

A ground state heterogeneity due to the presenee of an equilibrium between different eonformers. The relative orientations Trp-heme are rigid and different from one eonformer to another each conformer presents a speeifie fluoreseenee lifetime. The three exponential fluoreseenee decay from the hemoglobin rules out the presenee of the two static confonnations T and R supposed to be in equilibrium. 

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