摘要
在串级飞行时间质谱仪上用 53 2 nm激光溅射碳 /磷混合样品 ,所得团簇分为两类 :碳 /磷二元团簇离子和纯碳团簇离子 .纯碳团簇离子的相对强度随样品中磷含量的增加而变强 ,说明磷对纯碳团簇离子的形成具有重要作用 .而在所形成的碳 /磷二元团簇中 ,正离子主要有 Cn P+ 2 ( 0 <n<3 0 ) ,Cn P+ 3( 0 <n<2 2 )两类 ,而负离子则较多 ,有 Cn P- ( 0 <n<2 0 ) ,Cn P- 2 ( 0 <n<3 0 ) ,Cn P- 3( n为 2— 3 0间的偶数 )、Cn P- 5 ( n为 2— 2 0间的偶数 )四类 ,但没有 Cn P- 4 . Cn P+ 2 团簇离子的激光光解结果表明 ,其主要光解通道为剥落一个磷原子 .用B3 LYP/ 6-3 1 G* * 对 Cn P2 的结构进行分析 ,确定磷在两端的直线型链状结构为最稳定的结构 .此稳定结构与团簇的光解结果相吻合 .此外用同样的方法得到的 Cn P2 的电离能 ( PI)和电子亲合能 ( EA)出现了奇偶变化的现象 。
C/P binary clusters were produced by direct laser ablation of C/P mixed sample on a time of flight mass spectrometer. These clusters can be divided into two groups, C/P binary clusters and pure carbon clusters. The intensity of pure carbon clusters became stronger with the increase of P in mixed sample, which indicates that P has an important influence on the formation of pure carbon clusters. In C/P binary clusters, the compositions of the positive ions are only C n P + 2(0< n <30), C n P + 3(0< n <22), while the negative ions are more abundant than positive ions, which have compositions of C n P -(0< n <20), \{C n P - 2\}(0< n <30), C n P - 3( n is even number in 2—30), C n P - 5( n is even number in 2—20), but no C n P - 4 was produced. The photodissociation of C n P + 2 indicates that their main photodissociation channel was the loss of one P atom. Combining photodissociation and DFT calculations(B3LYP/6 31G ** ), the most stable structure of C 6P 2 positive ions should be the linear chain structure with P atoms at each end of the molecule. [WT5HZ]
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第4期581-585,共5页
Chemical Journal of Chinese Universities
基金
国家自然科学基金! (批准号 :2 9773 0 5 4)
关键词
激光溅射
碳/磷二元团簇
飞行时间质谱
结构
Laser ablation
C/P binary clusters
Time of flight mass spectrometry
Density
Function B3LYP
