Exploration of vibrationally resolved threshold photoelectron spectrum of difluoromethane within photon energy range of 12.45-14.10 eV  

12.45~14.10 eV光子能量范围内二氟甲烷振动态分辨的阈值光电子能谱研究

作　　者：Xueqi Cui Xinlang Yang Tongpo Yu Xiaoguo Zhou Shilin Liu 崔雪琪;杨新浪;于同坡;周晓国;刘世林(中国科学技术大学化学物理系,合肥微尺度物质科学国家研究中心,合肥230026;合肥工业大学物理系,合肥230009)

机构地区：[1]Hefei National Research Center for Physical Sciences at the Microscale,Department of Chemical Physics,University of Science and Technology of China,Hefei 230026,China [2]Department of Physics,Hefei University of Technology,Hefei 230009,China

出　　处：《Chinese Journal of Chemical Physics》2024年第6期754-762,I0041,共10页化学物理学报(英文)

基　　金：supported by the National Natural Science Foundation of China(Nos.22473104 and 22073088).

摘　　要：Threshold photoelectron spectrum of CH_(2)F_(2)in the photon energy range of 12.45-14.10 eV was re-investigated by means of a combination of photo-electron-photoion coincidence experiments and density functional theory calculations.A series of vibrational peaks were distinctly observed in this range.Using optimized geometries and vibrational frequencies of the CH_(2)F_(2)neutral and its cation in ground state at the M06-2X/cc-pVTZ level of theory,Franck-Condon factor simulations were conducted.Taking into account anharmonicity influences,a perfect agreement between the simulated and experimental spectra has been achieved.From the reliable vibrational assignments,adiabatic and vertical ionization energies of CH_(2)F_(2)are derived as 12.371±0.010 eV and 13.281±0.010 eV,respectively.In addition,the experimental frequencies of four vibrational modes with ai symmetry for CH_(2)F_(2)+(X^(2)B_(1))ions are determined.本文利用阈值光电子-光离子符合实验测量与密度泛函理论计算相结合的方法,对二氟甲烷的阈值光电子能谱进行了重新研究.在12.45~14.10 eV光子能量范围内,观测到具有明显振动结构.在M06-2X/cc-pVTZ水平上计算了CH_(2)F_(2)中性分子及其阳离子电子基态的几何优化构型和振动频率,在此基础上进行Franck-Condon光谱模拟,并进一步通过引入非谐性因子,获得了与实验光谱完美吻合的模拟光谱.基于这些可靠的振动光谱归属,确定了CH_(2)F_(2)的绝热电离能和垂直电离能分别为12.371±0.010 eV和13.281±0.010 eV,同时还得到了CH_(2)F_(2)+(X^(2)B_(1))离子四种a1对称性的振动模式频率.

关 键 词：Threshold photoelectron spectroscopy Franck-Condon simulation Vibrational frequency analyses Ionization energy CH_(2)F_(2) 

分 类 号：O56[理学—原子与分子物理]