For crystalline solid, the curve of scattered intensity vs. 2θ is almost zero everywhere except at certain angles where sharp peaks occur. Here, at these particular angle, the Bragg’s law, λ = 2dsinθ satisfied.
The monatomic gases, which have no structural periodicity whatever; in such gases, the atoms are arranged in a complete random order, and their relative positions change constantly with time. The XRD spectrum shows NO Scattering curve and has no maxima. However, a regular decrease of intensity was observed with the increase in scattering angle. The graph would be entirely horizontal, but the fact is isolated atoms scatter x-rays more intensely at low 2θ angles than at high
16 сен 2024
