Science and Technology Daily, Hefei, June 23 (Reporter Wu Changfeng) The reporter learned from the University of Science and Technology of China on the 23rd that the research team of Professor Zhao Jin from the School of Physics of the school cooperated with Professor Li Xinzheng of Peking University to discover the ultrafast charge transfer at the solid-molecular interface and proton The quantum dynamics of , are strongly coupled, revealing the important role of nuclear quantum effects in the charge transfer process.
The research results were recently published in Science Advances.
The solid-molecular interface is one of the most important prototype systems to study the solar energy conversion process, and the photo-excited carrier dynamics at the interface is one of the decisive factors to determine the solar energy conversion efficiency.
In typical solar energy conversion processes such as photocatalysis and photovoltaics, photoexcitation generates electron-hole pairs in semiconductor materials, and these excited carriers are then transferred to molecules through solid-molecular interfaces.
At many solid-molecular interfaces, complex hydrogen bond networks are formed between molecules, and protons are often transferred in such hydrogen bond networks. Therefore, the charge transfer at the solid-molecular interface is often coupled with the motion of protons. In such a process, people are faced with a complex quantum system, not only need to understand the dynamic behavior of electrons, but also need to consider the coupling with protons, and the protons moving in the hydrogen bond network, their own nuclear quantum effects are also It cannot be ignored that this has become a complex problem that has not yet been solved in this field.
The researchers solved this challenge by combining two cutting-edge computational methods in the field of first-principles computing, "non-adiabatic molecular dynamics (NAMD)" and "path-integral molecular dynamics (PIMD)".
They used NAMD to handle the electron dynamics part and a Ring-polymer molecular dynamics (RPMD) method based on path integral theory to handle nuclear quantum effects.
Using this scheme, they studied the kinetics of hole transfer at the methanol/titania interface and found that when methanol adsorbed on the titania surface forms a hydrogen bond network, protons are frequently transferred in the network, and the motion of these protons has obvious quantization. However, the trapping ability of the adsorbed methanol molecules for excited state holes is significantly improved due to the quantized motion of protons, thereby improving the efficiency of photochemical reactions.
On the one hand, this achievement reveals the important role of the formation of hydrogen bond networks and nuclear quantum effects in the ultrafast charge transfer process at the solid-molecular interface, and on the other hand, it is also helpful for the study of nuclear quantum dynamics and electron dynamics by first-principles calculations. The coupling provides new tools.