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

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

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UV Luminance Spectroscopy
Fluorescence occurs when

a molecule returns to the electronic ground state from an excited singlet state by losing it's excess energy as a photon
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 triplet state by losing it's excess energy as a photon

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UV Luminance Spectroscopy
Internal conversion is where

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

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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)
a molecule converts excess electronic energy to vibrational energy
a molecule converts its excess energy to light, and emits a photon
All of these

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

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

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