Wu, P; Hu, X; Yang, W, *λ-metadynamics approach to compute absolute solvation free energy*,
Journal of Physical Chemistry Letters, vol. 2 no. 17
(2011),
pp. 2099-2103 [doi] .
**Abstract:**

*We present a new approach to combine λ dynamics with metadynamics (named λ-metadynamics) to compute free energy surfaces with respect to λ. Particularly, the λ-metadynamics method extends metadynamics to a single virtual variable λ, i.e., the coupling parameter between solute and solvent, to compute absolute solvation free energy as an exemplary application. We demonstrate that λ-metadynamics simulations can recover the accurate potential of mean force surface with respect to λ compared to the benchmark results from traditional λ-dynamics with umbrella sampling. The solvation free energy results for five small organic molecules from λ-metadynamics simulations using the same filling scheme show that the statistical errors are within ±0.5 kcal/mol. The new λ-metadynamics method is general, and other variables such as order parameters to describe conformational changes can be easily combined with λ-metadynamics. This should allow for efficient samplings on high-dimension free energy landscapes. © 2011 American Chemical Society.*