首页|一氧化二氮的光解动力学:O(1D)+N2(X1∑+g)产物通道

一氧化二氮的光解动力学:O(1D)+N2(X1∑+g)产物通道

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由于一氧化二氮(N2O)在大气化学中的重要性,本文使用时间切片的离子速度成像技术重新研究了一氧化二氮在紫外吸收区域的光解离动力学.采用单色光测量了203.814 nm和205.472 nm光解产物O(1D)的离子影像,以及采用双色光记录了从200到220 nm范围八个光解波长下解离产物O(1D)的图像.产物N2(X1E+)碎片的转动态分布和各向异性参数的信息可以从图像中获取.实验结果表明,N2产物的转动态分布发生反转,最大值在J≈70.随着N2转动量子数J增加,各向异性参数β表现出两次显著的下降.根据前人的理论计算[J.Chem.Phys.136,044314(2012)],初始线性构型的轴向反冲程度的不同导致了β随J的变化.然而,在高J区域,非绝热跃迁之后的基态势能面上存在额外的扭矩,从而引起额外的转动激发和较低的β值.采用真空紫外单光子电离O(1D)原子的双色实验能够准确地获得产物的转动态分布和角分布.该工作加深了对三原子分子光解机制的进一步理解.
Photodissociation Dynamics of Nitrous Oxide:The O(1D)+N2(X1∑+g)Prod-uct Channel
Photodissociation of nitrous oxide(N2O)in the ultraviolet region has been revisited by using the time-sliced velocity map ion imaging technique,due to its importance in atmospheric chemistry.The images of O(1D)photofragments are recorded at 203.814 nm and 205.472 nm in one-color experiments and at eight photol-ysis wavelengths between 200 and 220 nm in two-color experiments.The rotational state distributions and an-gular anisotropy parameters of the N2(X1∑+g)co-products are derived from the images.The results indicate that the rotational state distributions are inverted with the maximum around J≈70.The anisotropy parameter β mainly shows two declines as the N2 rotational quantum number J increases.According to theoretical calculations[J.Chem.Phys.136,044314(2012)],the variations in β with J are caused by changes in the extent of axial re-coil from a linear initial configuration.In the high-J region,however,additional torque exists on the ground state potential energy surface following nonadiabatic transitions,inducing both the additional rotational excitation and the lower β values.Compared to previous works,the two-color experiments combined with single vacuum ultraviolet photonionization of O(1D)al-low us to acquire both the rotational state distribution and angular distribution accurately.This work deepens our understanding of triatomic molecule decomposition.

Ultraviolet photodissociationNitrous oxideTime-sliced velocity map ion imag-ing

杨帅康、巫雨承、罗子杰、李振兴、华伟、常尧、王兴安、袁开军、杨学明

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中国科学技术大学化学材料学院化学物理系,合肥 230026

中国科学院大连化学物理研究所,分子反应动力学国家重点实验室,大连光源科学研究室,大连 116023

大连海事大学轮机工程学院,大连 116026

合肥国家实验室,合肥 230088

南方科技大学理学院,化学系和先进光源中心,深圳 518055

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紫外光解离 一氧化二氮 离子速度成像 非绝热

国家自然科学基金国家自然科学基金National Natural Science Foundation of China(NSFC Center for Chemical Dynamics)Scientific Instrument Developing Project of the Chinese Academy of SciencesInnovation Program for Quantum Science and Technology广东省科技计划广东省科技计划深圳市科技计划

222413042222530322288201GJJSTD202200012021ZD03033042019ZT08L4552019JC01X091ZDSYS20200421111001787

2024

10.1063/1674-0068/cjcp2312135

化学物理学报(英文版)
中国物理学会

化学物理学报(英文版)

CSTPCDEI
影响因子：0.162
ISSN：1674-0068
年,卷(期)：2024.37(2)
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