Source: National Natural Science Foundation of China

Grant No: 21327804

Project: Liquid-beam photoelectron imaging spectrometer for the investigation of charge transfer processes in biomolecules

Chief Specialist: Prof. Bing Zhang

Introduction:

Direct measurement of electrons in biomolecules is of vital importance for understanding biological phenomena and physiological reaction mechanism. Liquid-beam photoelectron imaging, which combines photoelectron imaging with the advanced liquid-beam technique, allows for direct, comprehensive measurement of both the kinetic energy and angular distributions of photoelectrons of biomolecules in aqueous solutions. The kinetic energy and angular distributions of photoelectrons can provide information of the symmetry and other features of molecular orbits, as well as the configuration and alignment of the related molecules. Coupled with femtosecond pump-probe technique, it can obtain time-resolved photoelectron image and thus can be applied to observe the dynamics of the excited states of the aqueous biomolecules in real time, including the charge transfer process of intramolecules and the evolution of non-stationary states (i.e., wavepacket). This imaging setup not only requires higher vaccum, but also needs a well-desinged ionic lens system. At the same time, it also has to overcome electric discharging of the ionic lens system in low vaccum, remove pollution and match the sizes of the differentially pumped chambers. Compaired with the exisiting techniques of liquid-beam, such as hemispherical energy analyzer, time-of-flight, magnetic-bottle type spectrometer, the liquid-beam photoelectron imaging in this project has some advantages of higher collection efficiency of photoelectrons and direct measurement of the angular distribution of photoelectrons. The development of this technique can make up the disadvantage of the insufficient information obtained from the photoelectrons in aqueous solutions, and thus provides a new setup to measure liquid-beam photoelectrons, which will be further extended to the biomolecule-related scientific reasearches in various fields ranging from chemistry, physics to biology, medicine and so on.