X-Ray Study on the Binding Properties of Cu₂O and Ag₂O Crystals

Derivation of Inter-Atomic Force Constants of Cu₂O from Diffuse Neutron Scattering Measurement

“…The inter-atomic distances r and coordination numbers Z are shown in Table 2. The obtained lattice constant a = 4.2705(9) Å at 295 K matches well with the earlier reported value (a = 4.268(1) Å) [5]. The lattice constant at 295 K is less than that at 10 K, in agreement with the observation of the negative thermal expansion in this compound.…”

“…The crystal structure of Cu 2 O and Ag 2 O is of cuprite type as reported by T. Suzuki [5]. Cu 2 O and Ag 2 O show negative thermal expansion below 200 K [6,7].…”

“…The values of the correlation parameters of Cu 2 O are about 0.88 for the inter-atomic distance of r ~ 1.8 Å and ~ 0.73 for r ~ 3.0 Å at 295 K. The Debye-Waller temperature factor B and mean square displacement (MSD) Δr 2 are related directly as B = 8π 2 <Δr 2 >. The mean square of the thermal displacements of atoms <Δu ss' 2 > can be written in terms of correlation effects and Debye-Waller parameters with the definition of mean-square displacements (MSD) and displacement correlation function (DCF) [5,8],…”

The elastic constants of cuprous oxide

“…The value used for the density was 6.07 g/cm3, although Suzuki's [5] X-ray measurement of the lattice parameter gives 6.10 g/cm3 a t room temperature. The thermal expansion coefficient of Cu,O is quite small [5] (about 2 X 10-6/deg), so that no corrections were made for this. This can be expected to affect the total temperature change in the elastic constants by less than two percent.…”

Thermal Expansion Properties of Ag2O Crystal Structure by Powder Neutron Diffraction

“…The crystal structure of Ag 2 O is so called cuprite structure, and it belongs to the space group Pn3m (No. 224) [2]. The Ag atoms occupy 4b positions at (1/4 1/4 1/4) and the O atoms the 2a positions at (0 0 0).…”