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 increase the efficiency of the detector To prevent thermal degradation of the phosphorescent species 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 To decease the efficiency of detector 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 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
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) 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) ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy? 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 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 None of these ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Internal conversion is where None 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) None 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) 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? All of these Because a change in dipole moment lowers the energy required for electronic transitions 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 All of these Because a change in dipole moment lowers the energy required for electronic transitions 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 ANSWER DOWNLOAD EXAMIANS APP
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