fluorescence

TWO-TONE FLUORESCENCE

Brian Wagner, a chemistry professor at the University of Prince Edward Island, works with fluorescent dyes to develop molecular sensors for pesticides and other analytes. Here, he dissolved the fluorescent molecules perylene (top) and fluorescein (bottom) in the immiscible solvents hexane and water, respectively. Shining ultraviolet light on the solutions reveals two distinctly fluorescing layers.

Submitted by Brian Wagner, University of Prince Edward Island

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The Future

Ryan Pizante


a dress is still a uniform compartmentalized

wear your heels taut stomach skimmed

tuck the trunk below sharp hips

am I obvious

nectar is metallic

sap like barber’s blades bionic lacerations

swallow up the kitchen sink

tastes like empty when I smile

corset thread count lingerie spine

stitch me to you i’ll adapt

one vertebrae two seams

i wore a suit just vacant sheen

fluorescent admirers this future holds

am i expired or is my palette old

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Fluorescein

This chemical is a fluorophore, containing many aromatic groups and having the ability to absorb light and re-emit a new photon (fluorescence). There are other types of fluorescence that allow re-emission of light at higher energies or even the same energy but in this case the re-emitted light is at a lower energy. Because it is under a UV light, it absorbs the UV and the light that it re-emits will be visible to human eyes. Sadly, what we can see is only a very narrow band of the spectrum, still pretty awesome!

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This week something adorable will be posted: fluorescence thermochromism!

During the last few weeks I have prepared ~25 new, not yet described compound that have a weak or strong fluorescence thermochromism. This means they emit an other color under UV lamp at a different temperatures. Most of these compounds work at -195 °C where liquid nitrogen boils, but some of them show some effect at -100 to -70 °C. 

How do these work? Depending on the temperature the bonds in these molecules change a lot what means they can absorb and emit different wavelength. As seen on the pictures, on the first there are the compounds, each ampule contains 100 mg. When irradiated with UV light at room temperature (second pics) few of them emit some visible light, but when they are cooled down with liquid nitrogen (last pics) most of the compounds emit a different wavelength light with a different intensity.