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 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 triplet state 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 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 triplet state by losing it's excess energy as a photon ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy In the intersystem crossing 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) All of these a molecule converts excess electronic energy to vibrational energy ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why phosphorescence measurements are usually made at a low temperature? To increase the efficiency of the detector To decease the efficiency of detector To prevent thermal degradation of the phosphorescent species To promote phosphorescence by slowing the rate of radiationless transfer processes To increase the efficiency of the detector To decease the efficiency of detector To prevent thermal degradation of the phosphorescent species To promote phosphorescence by slowing the rate of radiationless transfer processes ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy What is the relationship between wavelength and wave number? None of these Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 Wavenumber - wavelength in nanometers = 1 None of these Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 Wavenumber - wavelength in nanometers = 1 ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why do fluorescence spectrometers often use double-beam optics? To compensate for power fluctuations in the radiation source 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 All of these To compensate for beam attenuation by the monochromator So a reference solution can be used 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 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 Because for absorption to occur, the radiation must interact with the electric field caused by changing dipole moment All of these 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 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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