In order to explore the hot electrons transfer mechanism of water splitting reaction, we show the dynamic process of H 2 O splitting in atomic sight by TDDFT/Ehrenfest dynamics in Figure , where we set ω 0 = 3.07 eV and E 0 max = 1.80 V/Å (the corresponding laser intensity is 4.30 × 10 13 W/cm 2 ). increases at first and reaches the maximum value 1.35 Å in t = 17.16 fs, then it decreases and oscillates until t = 30 fs. In other words, the water splitting reaction is asymmetric.