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Organic luminescent materials carryingno phenyl rings have attractedmuch interest from researchers due to their excellent biocompatibilityand good biodegradability, which make them available for potentialapplications in a variety of biomedical areas, such as fluorescentbioprobe, drug delivery and gene carrier, and provide a new insightinto the photophysical process of light emission. In this work, westudied the optical properties of poly[(maleic anhydride)-alt-(vinyl acetate)] (PMV), a pure oxygenic nonconjugatedpolymer and proved that the origin of its emission was associatedwith the clustering of the locked carbonyl groups. PMV exhibits solvatochromism:after interaction with electron-rich solvents, its absorption andemission shift to the longer wavelength region due to the formationof polymer/solvent complexes. This enables fine-tuning of its opticalproperty by varying the solvent without the need of changing the chromophore. [ABSTRACT FROM AUTHOR]

Vibrationally resolved fluorescence spectra of the β-hairpintrpzip2 peptide at two temperatures as well as during a T-jump unfolding process are simulated on the basis of a combinationof Markov state models and quantum chemistry schemes. The broad asymmetricspectral line shape feature is reproduced by considering the exciton–phononcouplings. The temperature dependent red shift observed in the experimenthas been attributed to the state population changes of specific chromophores.Through further theoretical study, it is found that both the environment'selectric field and the chromophores’ geometry distortions areresponsible for tryptophan fluorescence shift. [ABSTRACT FROM AUTHOR]