UV Luminance Spectroscopy
Fluorescence occurs when

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

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UV Luminance Spectroscopy
For a molecule to absorb IR, why must the molecule's vibrations cause fluctuations in the dipole moment of the molecule?

All of these
Because fluctuations in the dipole moment allow the molecule to deform by bending and stretching
Because a change in dipole moment lowers the energy required for electronic transitions
Because for absorption to occur, the radiation must interact with the electric field caused by changing dipole moment

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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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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
To allow for scattering by the sample
None of these
Because the magnitude of the output signal is proportional to the power of the incident radiation

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