Lecture 1 Flashcards
Define chromophore
light absorbing molecule or molecular fragment
Define lumophore
a luminescent molecule
Define fluorophore
a fluorescent molecule
Define phosphor
a phosphorescent molecule
Which luminescence type has an excited triplet state?
phosphorescence
Which luminescence type has an excited singlet state?
fluorescence
What is Stokes’ Shift?
the wavelength of emission is greater than the wavelength of absorption
Is the emission spectra dependent on excitation wavelength?
No, emission spectra only measures emission from S1 state, it is independent of the excitation wavelength
What is QY?
Quantum yield. The efficiency of photon emission. Photons in/photons out
What is the observed lifetime?
The average time a species spends in the excited state
What is the observed lifetime affected by?
Whether a transition is spin allowed or spin disallowed. Phosphorescence has a longer observed lifetime than fluorescence.
How does a steady state measurement work?
The sample is continuously illuminated. The emission intensity is measured against wavelength.
How does a time resolved measurement work?
The sample is exposed to a short pulse of illumination at a specific wavelength and the decay is measured as a function of time.
What is Kr?
Radiative rate
What is Knr?
Non-radiative rate
