Question: For a molecule to absorb IR, why must the molecule’s vibrations cause fluctuations in the dipole moment of the molecule? [A]. Because a change in dipole moment lowers the energy required for electronic transitions [B]. Because for absorption to…

Question: Why phosphorescence measurements are usually made at a low temperature? [A]. To prevent thermal degradation of the phosphorescent species [B]. To promote phosphorescence by slowing the rate of radiationless transfer processes [C]. To increase the efficiency of the detector…

Question: Why must the radiation source for fluorescence spectrometry be more powerful than for absorption spectroscopy? [A]. Because the magnitude of the output signal is proportional to the power of the incident radiation [B]. Because the sample won’t fluoresce if…

Question: Why do fluorescence spectrometers often use double-beam optics? [A]. So a reference solution can be used [B]. To compensate for beam attenuation by the monochromator [C]. To compensate for power fluctuations in the radiation source [D]. All of the…

Question: In the intersystem crossing [A]. the spin of an excited electron reverses, changing the state of the molecule (from singlet state to triplet state or vice versa) [B]. a molecule converts its excess energy to light, and emits a…