1. In essence, fluorescence spectrum is a transition of electronic state, while Raman spectrum is a transition of vibrational state. After molecules absorb the energy of electromagnetic radiation, electrons will jump from the base electron state to a higher energy state, and the energy required for the jump is equal to the absorbed photon energy.

2. Simply put, Raman is the frequency change after light scattering. Fluorescence is produced by molecules absorbing energy and then releasing energy due to collision.

3. The most direct excitation wavelength is Anton Paar 1064 or laser in ultraviolet region. The shorter the wavelength, the better. Over 200 nm, but short wavelength is hard to find. Anton Paar's 1064 can, and 1064 Raman should be more mature.

4. For the system excited by visible light, fluorescence is a headache. Moving the excitation wavelength to the ultraviolet or near infrared region may solve or reduce this kind of problem. There are too many indoor light sources in the laboratory, such as fluorescent lamps, incandescent lamps or fluorescent lamps, which will cause unnecessary background signals to the test spectrum.

5. The intermolecular interaction is much weaker than the intensity of infrared absorption spectrum. However, because its mechanism is electric quadrupole moment or magnetic dipole moment transition, it does not need the polarity of the molecule itself, so it is especially suitable for detecting symmetric molecules without polarity. Connection: Raman spectrum and infrared spectrum both occur in the infrared region.

6.Ramana Sang doesn't understand this phenomenon, and thinks it is secondary radiation caused by impurities, similar to fluorescence. Therefore, it is called "weak fluorescence" in the paper. However, Raman does not think that this is a phenomenon caused by impurities. If it is really the fluorescence of impurities, this effect should be eliminated in carefully purified samples.