Dear gmx-users, I am writing to clarify that the force constant kappa for g_wham corresponds to K_i itself, and not the quantity (1/2)*K_i in the umbrella potential W_i(ξ) = (K_i/2)*(ξ-ξ_i)^2. I recall reading somewhere that the force constant sometimes includes the (1/2) term in front of K_i, and sometimes not. Thank you, Lili