Fluorescence resonance energy thresholding

Ying, LM, Wallace, MI, Balasubramanian, S, and Klenerman, D, Ratiometric analysis of single-molecule fluorescence resonance energy transfer using logical combinations of threshold criteria A study of 12-Mer DNA. Journal of Physical Chemistry B 104 (2000) 5171-5178. 

The same system has been investigated by Moller and coworkers in helium droplets. At wavelengths above 100 nm (12.41 eV), which is below the ionization energy threshold for H2O at 98.4nm (12.61 eV), the fluorescence excitation spectrum is remarkably similar to that observed for the free molecules (See Fig. 7.11). In this experiment the well known Rydberg transitions of H2O were excited and the emission of OH (channel (1)) at 315 nm was recorded. No significant emission was observed either from resonant VUV emission or of the continuous visible radiation expected if the... 

A neodymium-ytterbium-coupled rare-earth ion system was given extensive study by Peterson and Bridenbaugh (109, 166) Peterson et al. (167) and Pearson and Porto (168). The simultaneous doping of Nao.5Gdo.5-W04, or Calibo (168) glass with neodymium and ytterbium results in a resonance-coupled system in which energy pumped into the neodymium appears as fluorescence from the ytterbium. The fact that the energy absorbed by the neodymium is rather efficiently transferred to the ytterbium results in a substantial reduction in laser threshold for ytterbium. 

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