The Earth's sky exhibits a faint luminescence known as airglow, which is caused by solar radiation initiated chemical reactions between atoms and molecules present in the upper atmosphere. The airglow provides important optical signatures of processes occurring in the atmosphere and studies of the airglow have driven the field of upper atmospheric science known as aeronomy.
　　OH Meinel band emission is an important contributor to the airglow in the Earth's mesosphere/lower thermosphere and has also been observed from the upper atmospheres of Mars and Venus.
　　More than 1700 OH Meinel lines have now been identified and assigned to transitions from high vibrational level of the ground state of the OH radical. Such vibrationally excited OH(X) radicals in the Earth's upper atmosphere have long been ascribed to products of the highly exothermic reaction of H atoms with O3.
　　The emission from OH radicals observed in the Earth's nightglow has been attributed to reactions involving vibrationally excited O3 molecules. However, it is challenged to study the OH dayglow.
　　Recently, Prof. YUAN Kaijun and Prof. YANG Xueming's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in cooperation with Prof. Michael N. R. Ashfold from University of Bristol and Prof. John M. C. Plane from University of Leeds, revealed the production of the vibrationally excited OH from water photochemistry and its role in the hydroxyl dayglow emissions in the atmospheres of Earth and Mars.
　　The study was published in Journal of Physical Chemistry Letters on October 13.
　　Dalian coherent light source reveals water photolysis and its contributions to hydroxyl dayglow emissions in Earth and Mars atmospheres (Image by CHANG Yao)
　　H2O photolysis is an important source of OH radicals in the interstellar medium. The scientists studied the photodissociation of H2O around 112.8 nm by utilizing the vacuum ultraviolet Free Electron Laser together with the H atom Rydberg tagging time-of-flight technique.
　　The results revealed that the formation of extremely vibrationally excited OH(X, high v) fragments, with inverted vibrational state population distribution, maximizes at v=9 and extends to at least v = 15.
　　Atmospheric chemistry modeling predicted that these OH(X, high v) radicals might be detectable in the OH Meinel band dayglow in the upper atmosphere of Earth and might dominate the corresponding emission from the Martian atmosphere.
　　Further, OH(A) emission was shown to be an indicator of H2O photolysis in the upper atmosphere of Earth and, more importantly, the OH(X, high v)/OH(A) emission ratio might be a direct diagnostic of the oxidation state of exoplanetary atmospheres.
　　This study was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the Chemical Dynamics Research Center, and the international partnership program of Chinese Academy of Sciences. (Text by CHANG Yao)

　　Carbonyl groups are ubiquitous in pharmaceuticals, natural products, and agricultural chemicals, especially amides. Transition metal-catalyzed decarbonylation offers a distinct synthetic strategy for new chemical bond formation and carbonyl groups transformation. However, the π-backbonding between CO π* orbitals and metal center d-orbitals impedes ligand dissociation to regenerate catalyst under mild condition.
　　Recently, a team led by Prof. CHEN Qing-an from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) developed a visible light-induced bifunctional rhodium catalysis for decarbonylative coupling of imides with alkynes under ambient conditions.
　　This study was published in Angew. Chem. Int. Ed. on Sep. 29.
　　Light-induced bifunctional rhodium catalysis for decarbonylation (Image by MIN Xiangting)
　　Initial mechanistic studies suggested that rhodium complex simultaneously served as the catalytic center and photosensitizer for decarbonylation. Under visible light irradiation, it generated the excited state Rh-complex where the transfer of an electron from the π-backbonding Rh-CO orbital into an antibonding orbital decreased the bond dissociation energy of the Rh–CO bond.
　　This visible light-promoted catalytic decarbonylation strategy offers new opportunities for carbonyl groups transformation.
　　This study was supported by National Natural Science Foundation of China, China Postdoctoral Science Foundation and Liaoning Revitalization Talents Program. (Text by MIN Xiangting)

　　The freezing of water is one of the most common everyday processes. However, understanding the microstructure of ice and its hydrogen-bonding networks has been a challenge.
　　The low-energy structures of water octamer are predicted to be nominally cubic, with the eight tri-coordinated water molecules at the eight corners of the cube. Such tri-coordinated water molecules have been identified at the surface of ice.
　　Only a few gas-phase studies have been achieved for experimental characterization of water octamer, and two nearly isoenergetic structures with D2d and S4 symmetry are found.
　　This understanding now has changed.A research team led by Prof. JIANG Ling and Prof. YANG Xueming from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. LI Jun from Tsinghua University, revealed the coexistence of five cubic isomers in the smallest ince cube, including two with chirality.
　　The study was published in Nature Communications on October 28.
　　Scientists discovered new structures in smaller ice cube (Image by LI Gang and LI Qinming)
　　Prof. JIANG and Prof. YANG developed a method of infrared spectroscopy of neutral clusters based on a tunable vacuum ultraviolet free electron laser (VUV-FEL). This method created a new paradigm for the study of vibrational spectra of a wide variety of neutral clusters that could not be studied before.
　　"We measured infrared spectra of size-selected neutral water octamer using the VUV-FEL-based infrared scheme" said Prof. JIANG.
　　"We observed the distinct features in the spectra, and identified additional cubic isomers with C2 and Ci symmetry, which coexisted with the global-minimum D2d and S4 isomers at finite temperature of the experiment," said Prof. YANG.
　　Prof. LI's team conducted quantum chemical studies to understand the electronic structure of the water octamer. They found that the relative energies of these structures reflect topology-dependent, delocalized multi-center hydrogen-bonding interactions.
　　The study demonstrated that even with a common structural motif, the degree of cooperativity among the hydrogen-bonding network created a hierarchy of distinct species. It provided crucial information for fundamental understanding of the formation processes of cloud, aerosol, and ice, especially under rapid cooling.
　　Their findings provide a benchmark for accurate description of the water intermolecular potentials to understand the macroscopic properties of water and stimulate further study of intermediate-ice structures formed in the crystallization process of ice. (Text by LI Gang and LI Qinming)

　　Glutathione S-transferases (GST) are one of the most important phase II detoxification enzymes. It achieves detoxification by catalyzing the nucleophilic attack of glutathione (GSH) on the electrophilic center of the target substrate, increasing its hydrophilicity to facilitate its transportation and exocytosis.
　　Compared with the normal counterparts, GST is frequently overexpressed in various cancers, and is thus regarded as a significant marker for multidrug resistant cancers. By virtue of their deeper penetration, lower background fluorescence, and convenient in vivo imaging, near-infrared (NIR) fluorescent probes exhibit higher practicability.
　　Recently, Prof. HAN Keli's group and Prof. PIAO Hailong's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences and their collaborators found that the holistic recognition performance of a fluorescent probe for GST was not only regulated by the recognition unit in the traditional meaning, but was also closely related to the eletron-deficiency of the fluorophore.
　　This study was published in Chemical Science on Sep. 21.
　　Fluorophore's electron-deficiency could affect the recognition performance of near-infrared fluorescent probes (Image by ZHANG Xuexiang)
　　The scientists introduced the NIR fluorophore HCy with a positive charge to replace the original two-photon fluorophore NI with the series of recognition units unchanged. They found that all HCy-based probes displayed stronger reactivity than the corresponding NI-based ones.
　　"We believed this phenomenon stemmed from the fluorophore's higher electron-deficiency other than its higher hydrophilicity," said Prof. HAN.
　　The resultant practical probes in HCy-series were those with weaker electron-withdrawing recognition units when comparing to NI3, which endowed the position 4 with a stronger –CN. This overturned –CN as the master key for all practical GST probes in previous literature.
　　Meanwhile, under the "signal amplifying" effect of this phenomenon, the selectivity distinction towards various GST isoenzymes triggered by the reactivity difference of the receptor units now could be distinguished. Subsequent imaging results in cells, tissues and living mice confirmed HCy2 and HCy9's practicality for detecting GST.
　　Additionally, although the fluorescent sensing of NIR probes was regarded as hard to modulate by photo-induced electron transfer (PET), researchers proved that the sensing mechanism for HCy-based probes is indeed PET, and the eletrophilicity would also in turn affect the efficiency of fluorescent sensing.
　　This work provides a beneficial inspiration and reference for designing fluorescent probes comprehensively.
　　It was supported by the National Natural Science Foundation of China, and the National Key Research and Development Program of China. (Text by ZHANG Xuexiang)

　　The superexcited molecule plays an important role as a reaction intermediate. The presence of high-energy radiation fields in the universe yields various superexcited molecules.
　　Understanding the fragmentation processes of the superexcited molecule is important in the upper atmosphere of the planets and in the photodissociation region (PDR) of the planetary nebula. However, the investigation of such processes is challenging due to the lack of energetic photons in a lab that excite the molecules to the extremely high-lying excited states.
　　With the advent of the intense, pulsed free-electron laser (FEL) in Dalian Coherent Light Source (DCLS) at Dalian, China, the photofragment study of molecules and radicals has become feasible for vacuum-ultraviolet (VUV) wavelengths below 100 nm using the high resolution translational energy spectroscopy.
　　Recently, Prof. YUAN Kaijun and Prof. YANG Xueming's group from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences, in collaboration with Prof. HU Xixi and Prof. XIE Daiqian from Nanjing University, revealed the electronically excited OH super-rotors in water photochemistry, for the first time.
　　This study was published in Journal of Physical Chemistry Letters on August 24.
　　The 3D product contour diagram from the photodissociation of H2O at 96.4nm (Image by CHANG Yao)
　　"We used VUV-FEL laser pulses with the wavelength of 96.4 nm to excite the water molecule to a high Rydberg state with the energy above its ionization potential, and then the H atom produced in the fragmentation of this superexcited water molecule was detected using HRTOF technique," said Prof. YUAN.
　　The experimental results indicated that the binary fragmentation channels H + OH and the triple channels O + 2H both present at 96.4 nm photolysis. Electronically excited OH super-rotors, with the internal energy just above the OH (A) dissociation energy, were observed for the first time, which were only supported by the large centrifugal barriers. The lifetime of these electronically excited OH super-rotors depended on the tunneling effect and predissociation effect.
　　"We recalculated the potential energy curves of OH, and found that even though the N = 36 pure rotational level of OH was already above its dissociation limit, the tunneling lifetime of this state through the centrifugal barrier was quite long (>2 year). However, the crossings of the ro-vibrational levels with the repulsive states caused severe predissociation," said Prof. HU.
　　The predissociation rate was several orders magnitude faster than the tunneling rate. As a result, the lifetimes of the OH super-rotors were around 370-57 ps. This suggests that these electronically excited super-rotors identified in the present work might have a role in the subsequent chemical reactions in the dense atmosphere.
　　This study was supported by the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the Chemical Dynamics Research Center, the international partnership program of Chinese Academy of Sciences, and the Key Technology Team of the Chinese Academy of Sciences. The theoretical work was supported by NSFC. (Text by CHANG Yao)

　　The slot-die coating is a promising deposition technique due to its advantages in low cost, high throughput, continuous roll-to-roll fabrication. However, it remains a challenge to control thin film uniformity over a large area at thickness as thin as 500 nm while maintaining crystallization quality.
　　Recently, a research group led by Prof. LIU Shengzhong from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) fabricated highly-efficiency large-area perovskite solar module using slot-die coating.
　　This study was published in Advanced Materials on October 20.
　　Schematic illustration of the evolution of perovskite film prepared via slot‐die coating with HPNE strategy (Image by DU Minyong and DUAN LianJie)
　　The scientists reported their development of an effective high-pressure nitrogen-extraction (HPNE) strategy that drove formation of a stable intermediate phase and allowed the coating to grow into a uniform dense perovskite film. As a result, they achieved a wide processing window in the large-area printing process.
　　Furthermore, an effective passivation process was developed using an ionic liquid to achieve solar cell efficiency as high as 22.7%. More importantly, the strategies were successfully scaled-up to large-area solar cell fabrication and a 40×40 mm2 perovskite solar cell (PSC) module attained stabilized power conversion efficiency as high as 19.4%, which was the highest efficiency for large-area module to date.
　　These results suggest that this controlled printing with HPNE strategy is a highly-efficient, wide-window, cost-effective, area-scalable technique for fabrication of PSCs, which will advance the development of slot-die coating as well as its application to high-throughput roll to roll deposition.
　　This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Nature Science Foundation of China, the Doctor Startup Foundation of Liaoning Province, the Innovation Fund Project of Dalian Institute of Chemical Physics, the Cooperation Foundation of Dalian National Laboratory For Clean Energy of the Chinese Academy of Sciences, the National Key Research Program of China, the 111 Project, and the Project of Knowledge Innovation Engineering. (Text by DU Minyong and DUAN LianJie)