Phosphorescence of mushrooms

[Foxfire]

Apparently, the terms 'phosphorescence' and 'fluorescence' are often not understood correctly. For example i was able to find some older books/articles describing fungal bioluminescence by googling "mushroom phosphorescence". But the misleading use of the terms is not just in older articles/books etc. 
With mushrooms, if the mushroom is at the same time bioluminescent in the dark, fluorescent under UV and phosphorescent when dried up, it would be great for demonstration that these types of luminescence are not the same things. 

[Andrea B.]

It's the short duration and weakness of the glow that makes it harder to capture

 

Yep, I'm not surprised that it is difficult for those reasons.

[Andrea B.]

Apparently, the terms 'phosphorescence' and 'fluorescence' are often not understood correctly.

 

Yes, I've seen that sometimes. 

 

I think bioluminescence is quite fascinating. I just looked up mushroom bioluminescence. They only glow at night to attract insects which help spread the spores during the more humid conditions at night which is more beneficial to the spores.

 

[Andrea B.]

...compared to fluorescence, a phosphorescence should be with longer wavelengths than fluorescence.

 

I'm not quite sure what you mean by that?

I have a calcite crystal which fluoresces pinky-orange under a 365nm UV-Led flashlight. Under a shortwave 254nm UV hand sanitizer light, the calcite phosphoresces blue. The phosphorescence doesn't last for too long. Maybe 10 seconds? 

 

BUT.... after reading this topic, I am wondering if what I thought was phosphorescence might be delayed fluorescence?? I'm not sure I understand how to determine this for a mineral.

 

[Foxfire]

9 hours ago, Andrea B. said:

...compared to fluorescence, a phosphorescence should be with longer wavelengths than fluorescence.

 

I'm not quite sure what you mean by that?

I have a calcite crystal which fluoresces pinky-orange under a 365nm UV-Led flashlight. Under a shortwave 254nm UV hand sanitizer light, the calcite phosphoresces blue. The phosphorescence doesn't last for too long. Maybe 10 seconds? 

 

BUT.... after reading this topic, I am wondering if what I thought was phosphorescence might be delayed fluorescence?? I'm not sure I understand how to determine this for a mineral.

 

 

There are some googleable diagrams that show it, that a phosphorescence is with longer wavelengths than fluorescence. But it would be nice to actually see it happening.

It might be that 254 nm does not excite the same elements as 365 nm, or it interacts with electrons that are not at the same energy levels or orbitals.

 

Delayed fluorescence is said to results in emission with the same spectral distribution as normal fluorescence, but with a much longer decay time. So it must have the same spectrum/color as a regular fluorescence. 

 

 

[Foxfire]

@Andrea B. the a more i could find is that delayed fluorescence emission is thermally activated and its efficiency increases with increasing temperature.
So a thing to do would be to freeze the mineral, and compare the color when it's warmed up.

 

But thanks for you interest, this makes me wonder if the mushrooms had actually also delayed fluorescence, or how common is it at all. Maybe there is both, a phosphorescence and delayed fluorescence.

[Lou Jost]

In the case of the delayed fluorescence of plants, which I mentioned above, the most important factor is the intensity of the excitation light. Temperature has only a minor influence. In this case the delayed fluorescence is closely related to the chemical processes involved in photosynthesis.

[Andrea B.]

Thank you Foxfire & Lou for the additional information.