Carbonic acid (H2CO3) plays a pivotal role as a proton donor in ocean acidification, enzymatic catalysis, and cellular metabolism. However, understanding its conformational transitions and dissociation kinetics in aqueous environments has remained challenging due to experimental and computational limitations. Here, we employ ab initio deep neural network-based molecular dynamics simulations to systematically investigate H2CO3's dissociation and proton transfer dynamics on nanosecond timescales. Our findings reveal that although the cis-trans (CT) conformer is less prevalent than the cis-cis (CC) conformer, it acts as the primary proton donor. Additionally, we elucidate the enhanced proton-donating ability of the CT conformer, attributing it to distinct features in its hydrogen-bond network topology and electronic structure.

Zhaoru Sun obtained her Bachelor's degree in Physics from Shandong University in 2009 and her Ph.D. in Condensed Matter Physics from the School of Physics at Peking University in 2014. From 2014 to 2018, she pursued postdoctoral research at Temple University in the US. In September 2018, she joined the School of Physical Science and Technology at ShanghaiTech University as an independent PI. She has been recognized as a Young Eastern Scholar and an Outstanding Young Talent by the Shanghai government, and has received support from the National Natural Science Foundation of China’s Youth Science Fund and the Shanghai Rising-Star Program. Her research centers on the structure and dynamics of water-related systems, and she has published extensively in journals such as Physical Review Letters, Proceedings of the National Academy of Sciences (PNAS), and Nano Letters.