Here, the hydrogen-bond formation function (h(t)) is a step function defined as 1 when the distance between each solute and solvent site is smaller than the first minimum of each RDF (Table ). Otherwise, h(t) is defined as 0. The TMAO/TBA•••H 2 O hydrogen-bond lifetimes (Table ) were evaluated by fitting p HB (t) to 𝑎𝑒 0! 1 ! ⁄ + 𝑏𝑒 0! 1 " ⁄ (𝑎 + 𝑏 = 1) to the data in the range 0.0 < t < 100 ps (Figure ); the double exponential fitting was applied since it provided better results than those from the single exponential fitting.