Analysis of the Fundamental Characteristics of Diamond-Like Crystals and Low-Dimensional Structures

Abstract

The principle has been developed for systematizing the diamond-like crystals with tetrahedral structure of the elementary cells and with valence chemical bonds, based on the calculation of the lattice constant. The approach proposed permits to predict basic parameters such as energy gap E g , electron affinity (optical work function) X, mechanical hardness H, melting temperature T m , optical phonon frequency etc. These parameters have been calculated and the table is presented for a number of chemical compositions. For materials with mixed chemical bonds (valence and ionic) the corrections can be calculated using Pouling electronegativity conception. The comparison with experiment demonstrates good agreement between the latter and the proposed procedure.

Charge‐transfer contributions in surface‐enhanced Raman scattering from Ag, Ag2S and Ag2Se substrates

“…The used laser light is sufficient to excite an electron from valence band to conduction band of Ag 2 S and then transfer to the unfilled level of 4‐Mpy, where the charge‐transfer resonance happened. For Ag 2 Se, the energy level is obtained by analogy with the data reported by Litovchenko and Belashchenko, which can be seen in Fig. .…”

Электронное строение монослойных сверхрешеток (GeC)-=SUB=-1-=/SUB=-(SiC)-=SUB=-1-=/SUB=-, (SnC)-=SUB=-1-=/SUB=-(SiC)-=SUB=-1-=/SUB=- и (SnC)-=SUB=-1-=/SUB=-(GeC)-=SUB=-1-=/SUB=-

“…Энергия обрезки плоских волн выбиралась равной 40 Ry, интегрирование по зоне Бриллюэна проводилось на сетках 6 × 6 × 6 (для кристаллов) и 6 × 6 × 4 (для СР). Путем оптимизации геометрии и минимизации полной энергии исследуемых кристаллов были вычислены сле-дующие значения постоянной решетки: 4.377 ¦ (SiC), 4.612 ¦ (GeC), 5.106 ¦ (SnC); которые адекватны дан-ным других авторов, например, [13][14][15][16][17][18] …”

In situ SeO2promoted synthesis of CdSe/PPy and Se/PPy nanocomposites and their utility in optical sensing for detection of Hg2+ions

“…If however the entire cation exchange reaction completes, the band-gap will drastically change and will reach near the band gap of HgSe which is reported to be in the range of 0.4-0.6 eV. This should therefore shi the absorption in the near infra-red range irrespective of possible size quantization effect, 61 Such a cationic interchange with ppm level amount of Hg 2+ ions can be considered an absorption based method for easy detection of Hg. Earlier report suggest the formation of HgSe on the surface and constant red-shi in the absorption and PL spectra for silica coated CdSe quantum dots and its reaction with Hg 2+ ions.…”