Overlap and Funnel Sampling in NEW Calculations

2 Overlap and Funnel Sampling in NEW Calculations Down the Funnel Phase Space Consideration 

To repeat briefly, the NEW method is related to free energy differences between systems 0 and 1 through Jarzynski s identity 

Key dashed curve - forward FEP, dash-dotted curve - reverse FEP, solid curve - direct FEP averaging, solid curve with crosses - simple overlap sampling, solid curve with open circles -overlap sampling with the optimal Bennett s weights. Data have units of kcalmol-1 

The linear parameter scaling approach of (6.9) is usually used to evolve the system from one state to the other. One disadvantage of such a scaling approach is that it offers no control of the phase space a path traverses. Instead, a similar parameter 7 (7 G [0,1], 7 = 0 and 1 for the 0 and T systems, respectively) can be used to describe progress along the path, e.g., 7 = 0— 71— — 7 — 7, — —  

7 = 1 where n is the total number of steps of the switch. The set of important configurations for the (intermediate) system defined by 7 is denoted r.  

---