UV Luminance Spectroscopy
Why phosphorescence measurements are usually made at a low temperature?

To decease the efficiency of detector
To prevent thermal degradation of the phosphorescent species
To promote phosphorescence by slowing the rate of radiationless transfer processes
To increase the efficiency of the detector

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UV Luminance Spectroscopy
In the intersystem crossing

the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa)
All of these
a molecule converts its excess energy to light, and emits a photon
a molecule converts excess electronic energy to vibrational energy

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UV Luminance Spectroscopy
Fluorescence occurs when

a molecule lowers its vibrational energy by losing it's excess energy as a photon
None of these
a molecule returns to the electronic ground state from an excited singlet state by losing it's excess energy as a photon
a molecule returns to the electronic ground state from an excited triplet state by losing it's excess energy as a photon

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UV Luminance Spectroscopy
Internal conversion is where

A molecule converts excess electronic energy to vibrational energy
None of these
the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa)
A molecule converts its excess energy to light, and emits a photon

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UV Luminance Spectroscopy
Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy?

To allow for scattering by the sample
Because the magnitude of the output signal is proportional to the power of the incident radiation
Because the sample won't fluoresce if the incident radiation is of low power
None of these

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