物理化学学报 >> 2014, Vol. 30 >> Issue (8): 1575-1580.doi: 10.3866/PKU.WHXB201405202

光化学和辐射化学 上一篇    下一篇

N2O+经由B2ПiX2П跃迁的光解离机理研究

吴丹, 张立敏, 周丹娜   

  1. 中国科学技术大学化学物理系, 合肥 230026
  • 收稿日期:2014-04-15 修回日期:2014-05-20 发布日期:2014-07-18
  • 通讯作者: 张立敏 E-mail:lmzha@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(21073177)资助项目

Study on the Photodissociation Mechanism of N2O+ via B2ПiX2П Transitions

WU Dan, ZHANG Li-Min, ZHOU Dan-Na   

  1. Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2014-04-15 Revised:2014-05-20 Published:2014-07-18
  • Contact: ZHANG Li-Min E-mail:lmzha@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21073177).

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B2ПiX2Π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B2Пi(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X2ΠB2Пi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B2Пi(00n)←X2Π(000)电子态跃迁的光解离机理和碎片离子的分支比.

关键词: 光解离, 一氧化二氮离子, Franck-Condon因子

Abstract:

Photofragment (NO+ and N2+) excitation (PHOFEX) spectra of N2O+ via B2ПiX2Π transitions was obtained over the wavelength range from 230 to 275 nm by preparing N2O+(X2Π(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 B2Пi(00n)←X2Π(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 B2Пi(00n)←X2Π(000) transition so as to estimate the validity of the rotational constants and the bond length of the B2Пi state obtained from previous studies. The photodissociation mechanism of the B2Пi(00n)←X2Π(000) transitions of N2O+ ions and the product branching ratios were also discussed.

Key words: Photodissociation, Nitrous oxide ion, Franck-Condon factor

MSC2000: 

  • O644