Water really matters

Previously, I wrote a post about meeting Roland Wester and the prospect of doing high resolution spectroscopy experiments on trapped ions of organic chromophores. Looking at a review Roland wrote about the technique led me to this beautiful JACS paper which desribes experiments on tryptophan [a flourescent amino acid]. The spectra below show how the protonated Trp has a broad absorption line due to non-radiative decay. Adding one and two water molecules, which hydrogen bond, removes this decay channel resulting in sharp vibrational features in the spectra.




The figures below show how the potential energy surface varies with twisting about the central carbon atom of the molecule.


Similar experiments on methine dyes such as the green flourescent protein chromophore would be wonderful!