UV Luminance Spectroscopy
Why do fluorescence spectrometers often use double-beam optics?

So a reference solution can be used
All of these
To compensate for beam attenuation by the monochromator
To compensate for power fluctuations in the radiation source

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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 increase the efficiency of the detector
To promote phosphorescence by slowing the rate of radiationless transfer processes

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UV Luminance Spectroscopy
In the intersystem crossing

All 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
Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy?

None of these
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
To allow for scattering by the sample

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UV Luminance Spectroscopy
Internal conversion is where

A molecule converts excess electronic energy to vibrational energy
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
None of these

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