Ab initio MRCI＋Q study on potential energy curves and spectroscopic parameters of low-lying electronic states of CS＋

Carbon monosulfide molecular ion （CS＋）, which plays an important role in various research fields, has long been attracting much interest. Because of the unstable and transient nature of CS＋, its electronic states have not been well investigated. In this paper, the electronic states of CS＋ are studied by employing the internally contracted multireference configuration interaction method, and taking into account relativistic effects （scalar plus spin–orbit coupling）. The spin–orbit coupling effects are considered via the state-interacting method with the full Breit–Pauli Hamiltonian. The potential energy curves of 18 Λ–S states correlated with the two lowest dissociation limits of CS＋ molecular ion are calculated, and those of 10 lowest Ω states generated from the 6 lowest Λ–S states are also worked out. The spectroscopic constants of the bound states are evaluated, and they are in good agreement with available experimental results and theoretical values. With the aid of analysis of Λ–S composition of Ω states at different bond lengths, the avoided crossing phenomena in the electronic states of CS＋ are illuminated. Finally, the single ionization spectra of CS （X1Σ＋） populating the CS＋（X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋） states are simulated. The vertical ionization potentials for X2Σ1/2＋, A2Π3/2, A2Π1/2, and B2Σ1/2＋ states are calculated to be 11.257, 12.787, 12.827, and 15.860 eV, respectively, which are accurate compared with previous experimental results, within an error margin of 0.08 eV~0.2 eV.     

新冠疫情常态化背景下大学物理实验教学实践

在新冠肺炎从突发应急状态进入常态化防控模式的背景下,针对大学物理实验课程提出"相近整合、线上线下结合"的教学方案,并以数字示波器和傅立叶级数两个实验为例予以实践.新课程重新审定课程目标,以此方案为指导,引入科学教学方法,并以调查问卷形式对课程效果进行调研和评价.实践结果表明,新教学方案在保证实验课程系统性、课程目标达成...     

Ab Initio Studies of Radicals HBX(X=H,F, Cl,Br): Molecular Structure,Vibrational Frequencies and Potential Energy

We describe high-level ab initio calculations on the BH_2, HBF, HBCl and HBBr radicals. Molecular structure,vibrational frequencies and potential energy curves of the ground state and the first excited state, which are two Renner-Teller components for a~2Π state at linearity, are studied using the basis sets aug-cc-pVTZ and icMRCI+Q technique. On the basis of the potential energy curves, a reliable potential energy barrier to dissociation HB+X(X=F, Cl, Br) fragments and to linearity are given. The ab initio results will add some understanding on the spectrum and the photo-dissociation dynamics of the series of radicals.     

弦线驻波实验装置改进

本文对典型弦线驻波实验中数据不够准确、驻波不稳定及实验可重复性差等现象进行了分析,明确其根本原因在于实验装置设计方案存在缺陷.提出了实验装置改进方案,一是引入拉力传感器取代狭缝刀口和悬挂重物,改变反射波的形成机理,并以弦线张力直接测量取代砝码重力间接计算;二是引入机械结构微调弦线长度以改变弦线张力和弦线上驻波波长.实验结果证明,改进后的实验装置能明显改善上述问题,该装置还可实施研究驻波规律的多个实验方案。     

2W2H教学法在大学物理实验中的教学实践

结合大学物理实验教学特点和现状,并基于PBL学习理论提出2W2H教学法,即“为什么做、学什么、怎么做、做得怎样”,帮助学生以四个问题为抓手构建学习主线、串联学习资源,促进学生提升主动学习意识和独立实验能力。该方法应用于大学物理实验课程中的数字示波器实验教学,以实例说明了该教学方法的思路和具体实施方案,实践结果证明了该方法的有效性。