The EFP-MD results indicated that the N + O -group of TMAO and the OH group of TBA captured three H 2 O molecules with an average lifetime of 31.2 and 16.5 ps, respectively. The calculated lifetime for TMAO agreed with those obtained by dielectric spectroscopy (at least 50 ps at ~300 K) and previous AIMD simulations (30-50 ps at 320 K; for D 2 O solution) . The hydrogen-bond lifetime near the CH 3 -group of TBA was 0.1 ps, while that near TMAO was significantly longer, 6.9 ps. It was confirmed that the CH 3 -groups of TMAO could capture water.