Gh. Grosch et Kj. Range, CHEMICAL TRENDS IN GOLD ALKALI ALLOYS - A DENSITY-FUNCTIONAL THEORY STUDY ON STABILITY AND CHARGE-TRANSFER .1. GOLD ALKALI ALLOYS OF THE FORMULA MAU, Journal of alloys and compounds, 233(1-2), 1996, pp. 30-38
Gold alkali alloys have roused the interest of both chemists and physi
cists since their discovery half a century ago. While experimentalists
tried to synthesize more and more new alloys filling up the homologou
s rows of compounds, the theoreticians tried to understand the astonis
hing properties of these alloys by doing more and more exact calculati
ons. The experimental and theoretical breakthroughs, however, took pla
ce only a few years ago, when single crystals could be synthesized and
examined and new powerful ab initio programs and supercomputers were
developed. Within the framework of density functional theory (in the l
ocal density approximation together with norm-conserving, scalar-relat
ivistic pseudopotentials) we calculate the structural properties of MA
u alloys comparing the stabilities of these alloys in NaCl, CsCl and N
aTl structures with each other and with experiment. Moreover, we exami
ne the electronic valence charge densities of these alloys and investi
gate the charge transfer in them by employing the concept of zero-flux
surfaces. We find that charge transfer occurs from the alkali to the
gold atom as expected. Moreover, we find a change from ionic to metall
ic binding between NaAu and LiAu.