UV Luminance Spectroscopy Fluorescence occurs when 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 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 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 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 a molecule converts excess electronic energy to vibrational energy 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 its excess energy to light, and emits a photon a molecule converts excess electronic energy to vibrational energy 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 its excess energy to light, and emits a photon ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy What is the relationship between wavelength and wave number? Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 None of these Wavenumber - wavelength in nanometers = 1 Wavenumber = 1 / wavelength in centimeters Wavelength in nanometers x wavenumber = 1 None of these Wavenumber - wavelength in nanometers = 1 ANSWER DOWNLOAD EXAMIANS APP
UV Luminance Spectroscopy Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy? To allow for scattering by the sample Because the magnitude of the output signal is proportional to the power of the incident radiation None of these Because the sample won't fluoresce if the incident radiation is of low power To allow for scattering by the sample Because the magnitude of the output signal is proportional to the power of the incident radiation None of these Because the sample won't fluoresce if the incident radiation is of low power ANSWER DOWNLOAD EXAMIANS APP
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 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 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
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