Recently, Prof. YUAN Kaijun's and Prof. YANG Xueming's Group at the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences revealed hydroxyl super rotors from water photochemistry by using Dalian Coherent Light Source (DCLS). Their findings were published in Nature Communications.
Hydroxyl super rotors produced from water photochemistry by using Dalian Coherent Light Source, the process of which is ubiquitous in the interstellar space. (Image by YUAN Kaijun)
Hydroxyl (OH) is a key radical in interstellar oxygen chemistry, because of its ability to react with most gases in the interstellar medium. Recently, OH radicals with extraordinarily high rotational levels of excitation have been observed in emission from some interstellar circumstances. Such rotationally “hot” OH radicals are very unlikely to be formed via any of the chemical reactions, but could originate from short wavelength photolysis of H2O.
In this work, “The advent of the intense, pulsed vacuum ultraviolet (VUV) free electron laser at the DCLS opens the way for state-of-the-art molecular photodissociation dynamics studies at any user-selected VUV wavelength” YUAN said. "Highly rotationally excited OH radicals, so-called "super rotors" existing above the bond dissociation energy, are observed from the photodissociation of water at 115.2 nm. Such peculiar dissociation dynamics are only observed at around 115.2 nm, which reveal interesting dissociation mechanisms." added YUAN.
The free electron laser facility provides a chance to investigate the VUV photochemistry of small molecules, which may happen frequently in interstellar space and should be recognized in appropriate interstellar chemistry models.
The research work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the Chemical Dynamics Research Center, and the National Natural Science Foundation of China. (Text by YUAN Kaijun)
