Analysis of far-infrared laser magnetic resonance spectra of CH2Br at 447.3 and 671.1μm

A simple model has been developed to describe the Zeeman patterns of far-infrared laser magnetic resonance spectra of the monobromomethyl radical CH₂Br observed at 447.3 and 671.1μm. A satisfactory agreement between the experimental spectra of the radical and their simulation with this simple model has been achieved. This approach can be used to gain further information about the structure and the spectrum of this interesting radical.     

非对称陀螺自由基分子光谱的标识分析──NO_2基振动态纯转动光谱分析

系统阐述了非对称陀螺分子光谱的标识分析工作涉及的一些关键理论问题, 包括有效Hamilton量、表象和基矢、能级识别、跃迁选择规则、相对强度和Zeeman调制率等, 并在有效Hamilton量中引入高阶离心畸变项, 大大提高了计算精度, 并使高转动量子数跃迁的标识分析成为可能. 作为应用实例, 对14N16O2基振动态的零场和磁共振谱进行了统一分析(global analysis), 获得了迄今为止最精确、最完整的14N16O2基振动态分子结构参数, 并对Curl和Brown等人过去未能标识的14N16O2高转动量子数跃迁远红外激光磁共振谱线进行了成功标识.     

最短网络

§1.楔子假设电话刚被发明,邮电部的第一个任务是要使北京、上海、兰州三个城市间有线路相通。你是总工程师,如何设计路线呢?第一个考虑是希望线路愈短愈好,以节省铺设电话线所需的材料、人工及土地。你知道两点间最短的距离是直线,所以电话线路原则上应该都是直线。你也想到了兰州到上海是这三条路线里最长的一条,但是如果有了另外那两条,这一     

Extended Measurement of the v2 (1- ←0+) Band of H3O+ by Mid-Infrared Diode Laser Spectroscopy

Twenty-five new R-branch lines of the v2（1^-← 0^＋） band of H3O^＋ are measured using diode laser velocity modulation spectroscopy between 1070 and 1230 cm^-1. The H3O^＋ ions are produced in a high voltage ac discharge with water diluted in helium. The observed lines together with all the previously published measurements are fit to the standard vibration-rotational Hamiltonian of an oblate symmetric top, yielding a set of improved molecular constants. All the sextic centrifugal distortion constants for both 0^＋ and 1^- states are determined precisely. The observed R（13, 0） transition is shifted about -0.129 cm^-1 from its calculated value, indicating that a near degeneracy exists between the （13, 0）^＋ and （13, 3）^- ground-state rotation-inversion levels.     

Spectroscopic analysis of asymmetric top free radicals——Application to pure rotational spectra of NO_2 in the ground vibronic state

Several key problems involved in the analyses of spectra of asymmetric top molecules, i.e., the effective Hamiltonian, the representation and basis vector, identification of energy levels, the selection rules, the relative intensity, and Zeeman tuning rate, were elucidated systematically. Introducing the high-order centrifugal distortion terms into the effective Hamiltonian, the precision for calculation has been improved substantially, which allows us to analyze the high-lying rotational transitions. A global analysis of all available spectra of 14N16O2 in the ground vibronic state has been made to obtain a set of molecular constants of 14N16O2 in the ground vibronic state which is the most precise and extensive so far. Using the improved parameters, some FIR LMR lines left unassigned hitherto have been identified successfully.     

双剑合璧彰显数学之美

数学中，有一些概念、定义、定理在结构上、性质上、用途上颇为相似，存在紧密联系．它们就像数学大家庭中的一对对“伴侣”一样，相互融合、相互渗透又相互作用、相互对比，共同诠释着数学的奥妙．笔者以高中数学几个经典知识为例，从分析数学的角度，让这一对对数学伴侣“双剑合璧”，以彰显数学别样之美．一、正、余弦定理“双剑合璧”，彰显数学“证明”之美     

COHERENT POPULATION TRAPPING IN MULTILEVEL LASER-INDUCED CONTINUUM STRUCTURE SYSTEM INCLUDING CASCADE TWO-PHOTON PROCESSES

We have investigated the atomic coherent population trapping in a mul tilevel laser-induced continuum structure system including cascade two-photon processes, in which two sets of quasicontinua of excited levels to be modeled as the Bixon-Jortner quasicontinuum are laser-embedded into a previously structu reless atomic continuum.The condition leading to the atomic coherent population trapping and the coherent population trapping state are given explicitly. And th e effects of the Fano factors, the laser intensities and the detunings on the am ount of population trapped in the atomic bound states and the populations distri buted in the two sets of quasicontinua are also examined.     

远红外激光磁共振光谱技术及对含碳自由基分子的观测

本文报道国内建成的远红外激光磁共振 (FIRLMR)光谱仪的技术特点和工作原理。该谱仪采用CO2 激光横向泵浦远红外激光 ,样品吸收池置于远红外激光谐振腔内 ,由聚丙烯薄膜与远红外激光增益池隔开以获得很高的灵敏度 ,从而对寿命很短的自由基分子进行研究。利用该光谱仪在远红外波段测量得到了多个瞬态自由基分子CCH ,CF和CH2 的光谱 ,这些自由基分子由微波放电产生的氟原子与甲烷CH4 反应生成。