Excited Atomic and Molecular States in Liquid Helium
The microscopic structure of dense gases and liquids and the nature of excited atomic and molecular states in dense media has been a subject of long standing scientific interest. For example the fluorescence of certain compounds when exposed to sun light has been known for hundreds of years, and very similar substances are important today as the active chemicals in modern dye lasers. The investigation into the chemistry of dense systems is an active area of research where many methods of initial excitation are used such as u.v. light, γ rays, α and β particle bombardment, mechanical shock, heat, etc. The first several spin singlet and spin triplet electronic energy levels of a complex molecule in a room temperature liquid can be thought of in terms of the diagram shown in Fig. 1.
KeywordsLiquid Helium Molecular State Excite Atomic Energy Level Diagram Superfluid Helium
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