Lack of Stability in the Stillinger-Weber Analysis, and a Stable   Analysis of the Potential Energy Landscape
  We examine the Stillinger-Weber analysis of the potential energy landscape for its stability and conclude that it does not provide a stable description of the system as the free energy slope and curvature vanish simultaneously. An alternative analysis developed recently by us involving complexity provides a stable description with complexity a monotonic increasing function of temperature. 
P. D. Gujrati