Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectr...Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectrometry （APi-TOF-MS） study of the sequential sodium halides series, C1-（NaC1）n and Br-（NaBr）m, has been reported, and the viability of the APi-TOF- MS equipped with an electrospray ionization source in determining cluster compositions has been demonstrated. The isotopic patterns were well resolved, as n=4 and 7 were determined to be the magic numbers for C1-（NaC1）n clusters, which were particularly abundant in the mass spectra. A global minimum search based on density functional theory enabled basin hopping yield the most stable structures for the mentioned series. The structures exhibit several distinct motifs which can be roughly categorized as linear chain, rock salt, and hexag- onal ring. This work provides an effective way to discover and elucidate the nonstoichiometry sodium halide clusters. These clusters possess very high vertical detachment energies and are generally called as superhalogens, which play important roles in chemistry because they are widely used in the synthesis of new classes of charge-transfer salts.展开更多
The size distribution and molecular structure of water clusters play a critical role in the chemical,biological and atmospheric process.The common experimental study of water clusters in aqueous solution is challenged...The size distribution and molecular structure of water clusters play a critical role in the chemical,biological and atmospheric process.The common experimental study of water clusters in aqueous solution is challenged due to the influence of local H-bonding environments on vibration spectroscopies or vacuum requirements for most mass spectrometry technologies.Here,the time-of-flight secondary ion mass spectrometry（To F-SIMS）combining with a microfluidic chip has been applied to achieve the in-situ discrimination of the size distribution for water clusters in liquid water at room temperature.The results demonstrated that the presented method is highly system stable,reproducible and accurate.The comparison of heavy water with pure water was made to further demonstrate the accuracy of this technique.These results showed that（H2O）3H-＋ and （D2O）4D-＋ are the most dominant clusters in pure and heavy water,respectively.This one water molecule difference in the dominant cluster size may due to the nuclear quantum effects on water’s hydrogen bonded network.It is the first time to experimentally show the size distribution of water clusters over a wide range（n=1–30）for pure展开更多
文摘Alkali halide clusters are interesting model systems that can provide information about how crystal properties evolve. To study these properties, a high-resolution atmospheric pressure inlet time-of-flight mass spectrometry （APi-TOF-MS） study of the sequential sodium halides series, C1-（NaC1）n and Br-（NaBr）m, has been reported, and the viability of the APi-TOF- MS equipped with an electrospray ionization source in determining cluster compositions has been demonstrated. The isotopic patterns were well resolved, as n=4 and 7 were determined to be the magic numbers for C1-（NaC1）n clusters, which were particularly abundant in the mass spectra. A global minimum search based on density functional theory enabled basin hopping yield the most stable structures for the mentioned series. The structures exhibit several distinct motifs which can be roughly categorized as linear chain, rock salt, and hexag- onal ring. This work provides an effective way to discover and elucidate the nonstoichiometry sodium halide clusters. These clusters possess very high vertical detachment energies and are generally called as superhalogens, which play important roles in chemistry because they are widely used in the synthesis of new classes of charge-transfer salts.
基金supported by the National Natural Science Foundation of China (21421004, 21705046)Innovation Program of Shanghai Municipal Education Commission (2017-01-07-00-02E00023)+2 种基金the Programme of Introducing Talents of Discipline to Universities (B16017)the Program of Shanghai Subject Chief Scientist (15XD1501200)the Fundamental Research Funds for the Central Universities (222201718001, 222201717003, 222201714012)
文摘The size distribution and molecular structure of water clusters play a critical role in the chemical,biological and atmospheric process.The common experimental study of water clusters in aqueous solution is challenged due to the influence of local H-bonding environments on vibration spectroscopies or vacuum requirements for most mass spectrometry technologies.Here,the time-of-flight secondary ion mass spectrometry（To F-SIMS）combining with a microfluidic chip has been applied to achieve the in-situ discrimination of the size distribution for water clusters in liquid water at room temperature.The results demonstrated that the presented method is highly system stable,reproducible and accurate.The comparison of heavy water with pure water was made to further demonstrate the accuracy of this technique.These results showed that（H2O）3H-＋ and （D2O）4D-＋ are the most dominant clusters in pure and heavy water,respectively.This one water molecule difference in the dominant cluster size may due to the nuclear quantum effects on water’s hydrogen bonded network.It is the first time to experimentally show the size distribution of water clusters over a wide range（n=1–30）for pure
