Imaging photodissociation dynamics of excited SiO molecules at 193 nm with laser ablation supersonic beam  

利用激光溅射超声分子束对激发态SiO分子在193nm下的光解动力学成像研究

作　　者：Yujie Ma Fangfang Li Dong Yan Ang Xu Ti Zhou Jiaxing Liu Fengyan Wang 马玉杰;李芳芳;闫东;徐昂;周倜;刘嘉兴;王凤燕(复旦大学化学系,上海市分子催化和功能材料重点实验室,能源材料化学协同创新中心,上海200438)

机构地区：[1]Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Collaborative Innovation Centre of Chemistry for Energy Materials(iChEM),Fudan University,Shanghai 200438,China

出　　处：《Chinese Journal of Chemical Physics》2024年第6期807-813,I0042,共8页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(No.22073019 and No.21327901);the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materials,and the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.

摘　　要：SiO is a wide-spread molecule found in interstellar space.Previous research has primarily focused on its spectroscopy,while its photodissociation dynamics is elusive to study due to high dissociation energy.Using time-sliced ion velocity imaging technique,we observed the Si(^(3)P)+O(^(3)P)photodissociation process resulting from the excitation of highly vibrationally excited SiO(X^(1)Σ^(+),υ=13-18)molecules to the SiO(A^(1)Π,E^(1)Σ^(+))states at 193 nm.The vibrationally excited SiO molecules were generated via laser ablation of silicon rod with the collision of the oxygen molecular beam acting as carrier gas and reaction gas.The bond dissociation energy D_(e)(Si-O)is determined to be 67253±110 cm^(-1)(8.34±0.01 eV)based on the kinetic energy distribution spectrum.The SiO photodissociation study has deepened our understanding of the mechanisms of silicon chemistry for silica-rich rocky meteors as they burn in the Earth's atmosphere,and the dissociation of SiO from ablation of meteoroids following ultraviolet photon absorption.SiO是星际空间中广泛分布的一种分子.由于该分子具有较高的解离能,之前的研究均聚焦于其光谱研究而鲜少聚焦在光解动力学研究上.本文利用时间切片-离子速度成像技术,观察到了高振动激发的电子基态SiO(X^(1)Σ^(+),v=13~18)在193 nm下激发至电子激发态SiO(A^(1)∏,E^(1)Σ^(+))并解离为Si(^(3)P)+O(^(3)P)的光解过程.此高振动激发的SiO分子由激光溅射固体硅棒并由氧气作为反应气和载气获得.根据实验得到的光解产物动能能谱,确定了SiO分子的解离能D_(e)(Si-O)为67253±110 cm^(-1)(8.34±0.01 eV).SiO的光解动力学加深了对富含岩石的流星在地球大气中燃烧时的硅化学反应,以及燃烧所产生的SiO在吸收紫外区光子后的光解反应机理的理解.

关 键 词：PHOTODISSOCIATION SIO Vibrational excitation Laser ablation Time-sliced ion velocity imaging 

分 类 号：P18[天文地球—天文学]