STUDY OF LASER RAMAN SPECTRA AND SYMMETRIZATION ANALYSIS OF TYPICAL SOLID STATE EFFECTS FOR X-RAY ANALYZER CRYSTAL

摘要

The main characteristic of molecular crystals RbC{sub}8H{sub}5O{sub}4, TlC{sub}8H{sub}5O{sub}4 and KC{sub}8H{sub}5O{sub}4 (they belong to isomorphous crystal) is that the structural units (milecyle or atomic group) which are located on crystal lattices essentially keep the shape and feature which they have in the free state. To this kind of low symmetrical crystal, we apply the theorem that the factor group of the space group P2{sub}1 ab, Z=4 (its group elements are {ε|0}, {σ{sub}y|τ(1/2,1/2,0)}, {σ{sub}z|τ(0,1/2,0)} and {C{sub}2{x}|τ(1/2,0,0)}) is isomorphic to the point group C{sub}(2v) and combine with the method of structural analysis, to classify the modes of internal vibrations of Rubidium Acid Phthalate RbC{sub}8H{sub}5O{sub}4 directly according to the compatibility relations of the irreducible representations. Then we get that the optical phonon modes in the centre of Brillouin zone k{sup}-≈0 is 180 internal vibration modes 47A{sub}1 + 47A{sub}2 + 43B{sub}1 + 43B{sub}2 36 external vibration modes 8A{sub}1 + 4A{sub}2 + 12B{sub}1 + 12B{sub}2 and that the 3 acoustical phonon modes A{sub}1 + B{sub}1 + B{sub}2 must be minus.