Xc. Zeng et al., SOME CONSEQUENCES OF THE ALPHA BETA BIFURCATION OF RELAXATIONS IN SUPERCOOLED LIQUIDS/, Journal of non-crystalline solids, 172, 1994, pp. 61-68
Because it is a doubly projected quantity and is related to correlatio
n functions of gradients of the intermolecular potential, the normaliz
ed second memory function corresponding to the relaxation of a dynamic
al quantity A(t) is taken to be a relaxation function dependent only u
pon collective modes and independent of the specific nature of the var
iable A(t). From this assumption alone the relaxation properties of ma
ny variables A(t) can be obtained and a rationale for the generalized
Stokes-Einstein relation can be given. Further, by assuming that this
memory function is biexponential, many of the properties characteristi
c of systems which exhibit bifurcation of their slow relaxations into
alpha and 'slow beta' processes can be obtained.