Question

For glasses:
How does the grain diameter behave based on the color and how does it affect the spectrum?

Answer 1

The phonon lifetime is modified due to phonon-phonon interaction and free surface and grain boundary scattering

Relative to microstructural (MSM) metals and alloys, the NSM contain a higher fraction of grain boundary volume (for example, for a grain size of 10 nm, between 14 and 27% of all atoms reside in a region within 0.5–1.0 nm of a grain boundary); therefore, grain boundaries play a significant role in the materials properties. Changes in the grain size result in a high density of incoherent interfaces or other lattice defects such as dislocations, vacancies, etc. As the grain size d of the solid decreases, the proportion of atoms located at or near grain boundaries relative to those within the interior of a crystalline grain, scales as 1/d. This has important implications for properties in ultra-finegrained materials which will be principally controlled by interfacial 12 properties rather than those of the bulk.

Absorption (fluorescence) spectrum of Na atom relates to the transition 2S – 2P. The spectrum of Na3 cluster expands into the discrete molecular spectrum reflecting electron excitations and atom oscillations. Continuous spectrum of Na8 cluster reflects the processes of dissociations and defragmentation of cluster on atoms. Spectrum of nanoparticle reflects Transformation of absorption spectra of sodium from atom to solid Spectrum of nanoparticle reflects resonance absorption of cluster atoms. Spectrum of massive film reflects the interband transitions of electrons in metal

Blue shift refers to a shortening of a transmitted signal's wavelength, and/or an increase in its frequency. The name comes from the fact that the shorter-wavelength end of the optical spectrum is the blue end, hence, when visible light is compacted in wavelength, it is "shifted towards the blue", or "blue-shifted