Hi, While experimenting with various LED's in LN2, I noticed some strange behaviour from my green LED's. As expected all LED's (except the green one's) emitted light with a shorter wavelenth (for instance, my yellow led turned to red etc). However, my 2 (different manufacturer type LED) green LED's turned yellow'ish in liquid nitrogen. At first I thought this had to do with some property of the LED, but the second green LED showed the same shift (to a higher wavelength). I've thought about this a lot, but I can't think of any reason why the green LED's don't turn blue'ish. Any suggestions how to tackle this (for me still unsolved) mistery? Thanks in advance!