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

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

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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?

Because a change in dipole moment lowers the energy required for electronic transitions
All of these
Because fluctuations in the dipole moment allow the molecule to deform by bending and stretching
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
Fluorescence occurs when

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
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
In the intersystem crossing

a molecule converts excess electronic energy to vibrational energy
All 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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