N_2O^+经由B^2П_i←X^2П跃迁的光解离机理研究  

Study on the Photodissociation Mechanism of N_2O^+ via B^2П_i←X^2П Transitions

作　　者：吴丹[1] 张立敏[1] 周丹娜[1] 

机构地区：[1]中国科学技术大学化学物理系,合肥230026

出　　处：《物理化学学报》2014年第8期1575-1580,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21073177)资助项目~~

摘　　要：在超声分子束条件下,利用360.50 nm的电离激光使N2O分子经由[3+1]共振增强多光子电离(REMPI)产生纯净的N2O+(X2Π(000))分子离子,用另一束解离激光在230-275 nm范围扫描获得N2O+经由B2Πi←X2Π跃迁产生的光解碎片(NO+和N2+)激发(PHOFEX)谱.获得的光解碎片激发谱可以归属为B2Πi(00n)←X2Π(000)序列跃迁.我们分别将线性三原子分子离子N2O+中N―N伸缩振动简化成NO和N之间的简谐振动,N―O伸缩振动简化成N2和O之间的简谐振动,用谐振子的简谐势能曲线和波函数对N2O+分子离子X2Π和B2Πi电子态振动能级间跃迁的Franck-Condon因子进行计算,和实验得到的碎片离子增强谱实验强度进行比较,对前人给出的分子数据(分子平衡核间距)进行验证,讨论了N2O+经由B2Πi(00n)←X2Π(000)电子态跃迁的光解离机理和碎片离子的分支比.Photofragment （NO＋ and N2＋） excitation （PHOFEX） spectra of N2O＋ via B2∏i←X^2∏ transitions was obtained over the wavelength range from 230 to 275 nm by preparing N2O＋（X^2∏（000）） ions via [3＋1] resonance enhanced multiphoton ionization of N2O molecules at 360.50 nm. On the basis of the approximation of harmonic oscillation between N and NO or between N2 and O, the Franck-Condon factors for the B2∏i（00n）←X^2∏（000） transitions of N2O＋ ions were calculated using the potential curves and wavefunctions of the harmonic oscillator. The results of such calculations were compared with the photodissociation spectra of the B2∏i←X^2∏（000） transition so as to estimate the validity of the rotational constants and the bond length of the B^2∏i state obtained from previous studies. The photodissociation mechanism of the B2∏i←X^2∏（000） transitions of N2O^＋ ions and the product branching ratios were also discussed.

关 键 词：光解离 一氧化二氮离子 FRANCK-CONDON因子 

分 类 号：O613.61[理学—无机化学] O641.1[理学—化学]