Neutral cluster infrared spectroscopy experimental method of Dalian coherent light source developed by Dalian Institute of Chemical Research

[ Instrument Network Instrument R & D ] Recently, Jiang Ling, a researcher at the State Key Laboratory of Molecular Reaction Dynamics in the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Yang Xueming, an academician of the Chinese Academy of Sciences, and Zhang Donghui's team, in collaboration with Professor Tuan Li of Tsinghua University in the research of neutral water cluster New progress has been made and experimental methods for neutral cluster infrared spectroscopy based on Dalian coherent light sources have been developed.

Clusters are widely used in many chemical processes such as energy catalysis and atmospheric haze. The study of cluster characterization and performance is very important to explain the chemical reaction mechanism. At present, ion clusters are mostly studied, and neutral clusters are lack of charge and difficult to detect, so there are few related experimental studies. The bottleneck is mainly due to the lack of suitable UV light source. The Dalian coherent light source completed in 2017 is a free electron laser user device currently operating in the extreme ultraviolet band. It has high brightness and pulse time characteristics, can effectively achieve single photon threshold ionization, and is very suitable for neutral molecules and clusters. High sensitivity and high time resolution detection and research.

In view of the above, Jiang Ling and Yang Xueming's team developed an experimental method of neutral cluster infrared spectroscopy based on Dalian coherent light source for high-sensitivity detection, structural characterization and performance research of mass-selected neutral clusters.

Water is the source of life, and water molecule dimer ((H2O) 2) is a model system for studying the mechanism of hydrogen bonding between ice and liquid water. However, the infrared spectral designation of (H2O) 2 is still controversial. In this work, Jiang Ling and Yang Xueming's team carried out a detailed study of (H2O) 2 neutral clusters by using an independently developed experimental station for neutral cluster infrared spectra based on Dalian coherent light sources. Group of spectral peaks; Zhang Donghui's team calculated the infrared spectrum using the self-developed full-dimensional potential energy surface dynamics method, and accurately pointed these four sets of spectral peaks as OH stretching vibration modes in different chemical environments; Li Yi's team used molecular orbitals The theory analyzes the bonding characteristics and explains the distribution law of OH stretching vibration. These research results help to understand the infrared spectrum and structural characteristics of complex systems.

Since the wavelength range of the Dalian coherent light source covers the first ionization potential of most neutral molecules and clusters, this work involves the structure and performance of neutral clusters, the detection of catalytic reaction intermediates and free radicals, and the formation of aerosols. Cutting-edge scientific research in nuclear mechanisms, biomolecular characterization, and other fields provides new strategies.

Related results were published in The Journal of Physical Chemistry Letters. This work has been supported by the National Natural Science Foundation of China's Dynamic Chemistry Frontier Research Center Project, the Chinese Academy of Sciences Strategic Pilot Project (Class B) "Essence and Regulation of Energy Chemical Conversion", the Natural Science Foundation Project, and the Dalian Institute of Chemical Technology Dalian Coherent Light Source Fund. Funding.