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 returns to the electronic ground state from an excited triplet 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

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UV Luminance Spectroscopy
In the intersystem crossing

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

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UV Luminance Spectroscopy
Internal conversion is where

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

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

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

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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 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
Because a change in dipole moment lowers the energy required for electronic transitions
All of these

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