Ar. George et Cra. Catlow, THE COMPUTATIONAL INVESTIGATION OF THE PHASE-TRANSITION FROM THE GEO2ALPHA-QUARTZ STRUCTURE TO THE RUTILE STRUCTURE, Journal of solid state chemistry, 127(2), 1996, pp. 137-144
We report a detailed computational investigation using several techniq
ues relating to the phase transition from the alpha-quartz to the ruti
le structure for GeO2 and GeO2/SiO2 solid solutions. We calculate an a
ctivation barrier of approximately 47 kJ mol(-1) for the phase transit
ion, which is in good agreement with the most recently reported experi
mental value. We also identify a number of interesting intermediate st
ructures, in which Ge is present in two coordination environments (fou
rfold and sixfold). These complex intermediates have characteristics a
kin to the experimentally observed amorphous systems. (C) 1996 Academi
c Press.