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

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

ANSWER DOWNLOAD EXAMIANS APP

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

ANSWER DOWNLOAD EXAMIANS APP

UV Luminance Spectroscopy
In the intersystem crossing

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)
a molecule converts excess electronic energy to vibrational energy

ANSWER DOWNLOAD EXAMIANS APP

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

None of these
To allow for scattering by the sample
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

ANSWER DOWNLOAD EXAMIANS APP

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

ANSWER DOWNLOAD EXAMIANS APP