Method of generating excited state
The main are: ① light excitation. Atoms or molecules in the ground state absorb photons of a certain energy and can transition to the excited state. This is the most important method for generating excited states. ② Discharge. It is mainly used to excite atoms, such as high-pressure mercury lamps and xenon arc lamps. ③ Chemical activation. Some exothermic chemical reactions may cause electrons to be excited, resulting in chemiluminescence.