Conclusion

The problem of the interaction of the gaseous phase with the lattice of asolid incorporates two types of problems. The first group consists of problems dealing with the interaction of an adsorbed particle with an adsorption center. Here both the electrons of the particles being adsorbed and those of the particle at which the adsorption takes place are involved. This group of problems is commonly known as the local interaction problem. But there are also entirely different problems, which chemists call problems of collective interaction. Here the interaction of the adsorbed particle with the entire lattice is studied, and the entire collection of free electrons and holes of the lattice come into play.