Etude par diffraction des rayons X du gallium liquide entre +50 et −110 °C

Abstract

Une étude par diffraction des rayons × du gallium liquide a été effectuée entre les températures +50 et −110 °C. Sur les diagrammes d'intensité diffusée, on observe qu'un pic secondaire „adjoint”︁ au pic principal prend une importance croissante lorsque la température diminue. Cependant, les fonctions de distribution radiale n'indiquent pas de changement notable avec la température, c'est‐à‐dire que le nombre de voisins et la position des maxima ne varient pas de façon significative. La comparaison des fonctions de distribution de paire du gallium liquide et des phases cristallines dont la structure est connue, montre que la répartition atomique dans le liquide présente des analogies plus marquées avec les distributions des atomes dans les formes cristallines métastables qu'avec celle de la forme stable.

Quasi-elastic neutron scattering from liquid gallium over the temperature range 163 to 333 K

“…The top portion of figure 6 shows this elastic scattering measured by the central counter at two temperatures : above the normal melting point at 333 K and in the supercooling state at 213 K. The same sample was used in each case so the relative intensities are comparable. The curves have the same qualitative form as the total scattering curves measured by X-ray diffraction [11] and shown by full line in the lower part of figure 6. We note however that the elastic scattering presents a more pronounced temperature dependance.…”

“…the maximum in the liquid structure factor S(Q) and showed that S(Qo) should diverge as the stability limit is approached. There have been several recent experiments measuring S(Q ) by X-ray scattering in supercooled liquid gallium [11,12]. In particular the experiments of Bizid et al have been performed at temperatures down to near the lowest temperature at which gallium has ever been obtained in the liquid phase, and show that there is no tendency to any divergence in S(Q).…”

Ion - ion and electron - ion correlations in liquid gallium

“…This specificity has to be linked with some other of its physical properties: its low temperature of fusion, its pronounced tendency towards undercooling, the increase of its density on melting by about 3%, the fact that it can solidify in at least four crystalline metastable phases, and so on. Besides this, the shoulder moves to a subsidiary peak during the undercooling (Bizid et al 1974).…”

Temperature Dependence of the Liquid Structure of Ga

“…It has long been known for many measurements [1][2][3][4][5][6][7][8][9][10][11][12] that the liquid structure of Ga is not simple. There exists a subsidiary interference maximum on the high angle side of the principal interference peak.…”