  An analytical framework is proposed to describe the elasticity, viscosity and
fragility of metallic glasses in relation to their atomic-level structure and
the effective interatomic interaction. The bottom-up approach starts with
forming an effective Ashcroft-Born-Mayer interatomic potential based on
Boltzmann inversion of the radial distribution function g(r) and on fitting the
short-range part of $g(r)$ by means of a simple power-law approximation. The
power exponent $\lambda$ represents a global repulsion steepness parameter. A
scaling relation between atomic connectivity and packing fraction $Z \sim
\phi^{1+\lambda}$ is derived. This relation is then implemented in a
lattice-dynamical model for the high-frequency shear modulus where the
attractive anharmonic part of the effective interaction is taken into account
through the thermal expansion coefficient which maps the $\phi$-dependence into
a $T$-dependence. The shear modulus as a function of temperature calculated in
this way is then used within the cooperative shear model of the glass
transition to yield the viscosity of the supercooled melt as a
double-exponential function of $T$ across the entire Angell plot. The model,
which has only one adjustable parameter (the characteristic atomic volume for
high-frequency cage deformation) is tested against new experimental data of
ZrCu alloys and provides an excellent one-parameter description of the
viscosity down to the glass transition temperature.
