高氮含量钠杂氮团簇的生成与检测

Formation and Detection of Na-doped Nitrogen Clusters NaNn^+with High Nitrogen Content

为了将NaN3及NaN3分别与BN、ZrN、Ti混合粉末(摩尔比1∶1)经压片机制成直径为13mm、厚度为2~5mm的底物,使用高纯氮气为反应气体和载气,采用液氮冷却离子源,经激光溅射生成了钠杂氮团簇NaNn+(n=2、4、5、6、7、8、9、10、11、12),采用反射式飞行时间质谱仪检测并获得了其质谱图。结果表明,不同底物生成的钠杂氮团簇具有不同特点,激光溅射NaN3和NaN3/BN混合物分别生成了4种钠杂氮团簇NaN+n(n=2、4、6、8),但是其离子峰相对强度随氮原子数变化的趋势不同;激光溅射NaN3生成的钠杂氮团簇离子峰相对强度随氮原子数从2到6逐渐增高,到8时降低,而激光溅射NaN3和NaN3/BN混合物生成的钠杂氮团簇离子峰的相对强度随氮原子数增加单调下降;激光溅射NaN3/ZrN混合物生成了不同于NaN3和NaN3/BN混合物的钠杂氮团簇NaN+10和NaN4(H2O)+,最大氮原子数达到10。其中以NaN3/TiN混合样品为底物生成的钠杂氮团簇NaNn+种类最多、含氮量最高,氮原子数最多的团簇为NaN12+,NaN12+的含氮质量百分数达到约88%。

In order to form a substrate with diameter of 13mm and thickness of 2-5mm by pressing the mixture of NaN3 and NaN3 with BN,ZrN and Ti respectively(molar ratio of 1∶1),high-purity nitrogen was used as reaction gas and carrier gas,liquid nitrogen was used to cool the ion source,and the NaNn+(n=2,4,5,6,7,8,9,10,11,12)was produced by laser sputtering,and the mass spectrum was obtained by using the reflection time of flight mass spectrometer.The results show that there are different characteristics of NaNn+clusters formed by different substrates.Four kinds of NaNn+clusters(n=2,4,6,8)were formed by laser sputtering of the mixture of NaN3 and NaN3/BN.However,the relative intensity of the ion peak varies with the number of nitrogen atoms;the relative intensity of the ion peak of the NaNn+cluster formed by laser sputtering increases with the number of nitrogen atoms from 2 to 6,and decreases with the number of nitrogen atoms,while the relative intensity of the NaNn+cluster formed by laser sputtering the mixture of NaN3 and NaN3/BN decreases monotonously with the number of nitrogen atoms;the formation of the NaN3/ZrN mixture by laser sputtering different from the mixture of NaN3 and NaN3/BN,were clusters NaN+10 and NaN4(H2O)+,and NaN+10 have a maximum nitrogen atom number of 10.Among them,the most species and nitrogen content of sodium hetero nitrogen cluster was formed by using NaN3/TiN as substrate,the most number of nitrogen atoms cluster is NaN12+,and the nitrogen content percentage of NaN+12 is about 88%.