用两束真空紫外激光和离子速度成像方法测量~(12)C~(16)O分子在108000～113200 cm~(-1)能量范围的解离通道分支比:生成O(~1D)通道的观测（英文）

本文利用两束可调谐真空紫外激光和离子速度成像的方法测量了CO在108000～113200 cm~(-1)光解离通道分支比[C(~3P_0)+O(~1D)]/{[C(~3P_0)+O(~3P)]+[C(~3P_0)+O(~1D)]}和[C(~3P_2)+O(~1D)]/{[C(~3P_2)+O(~3P)]+[C(~3P_2)+O(~1D)]}.本文先用一束真空紫外激光将CO分子激发至特定的高激发量子态并发生解离,接着用另一束真空外激光选择性地电离C(~3P_0)和C(~3P_2)并进行探测.1VUV+1UV/visible共振增强多光子电离的方法大大提高了实验的探测灵敏度,使得之前没有观测到的较弱的吸收带也首次被观测到.通过分支比的测量,发现自旋禁阻的解离通道C(~3P_0)+O(~1D)和C(~3P_2)+O(~1D)只在某些分立的较窄能量范围内才能被观测到.这可能是由于直接激发的高里德堡态和解离到上述自旋禁阻通道的价态在这些能量范围内发生了共振的自旋-轨道耦合相互作用.     

二硫化碳分子在204 nm附近的光解离动力学研究：S(3PJ)+CS(X1Σ+)产物通道

本文用时间切片离子速度影像技术研究CS₂分子在204 nm附近的光解离动力学. 在201.36、203.10、204.85和206.61 nm这四个解离波长下,实验清楚地观测到S(³P_J)+CS(X¹Σ⁺)产物通道. 在实验获得的S(³P_J=2,1,0)影像中,对应的CS(X¹Σ⁺)产物的振动态结构得到了部分的分辨. 通过对影像的分析,还获得了解离的总平动能谱以及产物的各项异性参数. 实验观察到的相对小的各项异性参数表明产物更倾向于经历了间接的光解离过程. 这一通道的自旋－轨道禁阻特征也说明了非绝热效应在二硫化碳紫外光解离生成S(³P_J=2,1,0)+CS(X¹Σ⁺)的过程中发挥了重要作用.     

OCS分子在里德堡F态的真空紫外光解动力学：S(3PJ=2,1,0)产物通道

本文利用可调谐真空紫外光源和时间切片离子速度成像技术研究了OCS分子的真空紫外光解动力学. 在对应OCS里德堡F态的五个光解波长下(133.26 nm∽139.96 nm)实验采集了S(³P_J=2,1,0)产物的离子影像,从中发现了两个解离通道：S(³P_J=2,1,0)+CO(X¹Σ⁺)和S(³P_J=2,1,0)+CO(A³π),其中前者为主要通道. 离子影像中CO产物的振动结构可部分分辨. 从离子影像中提取出了S(³P_J=2,1,0)+CO(X¹Σ⁺)通道的产物总平动能分布、各向异性参数和CO振动态分支比等信息. 发现了对应OCS在F态的几个低振动态下光解的产物各向异性参数取负值,而对应F态的几个高振动态下光解产物的各向异性参数为正值. 另外,同一光解波长下三种S产物S(³P₂)、S(³P₁)和S(³P₀)的各向异性参数也不相同. 经分析,这些现象可能来源于激发区域的其它不同对称性的电子态的贡献,从而导致解离过程中同时存在平行解离和垂直解离. 本工作有利于进一步理解OCS真空紫外光解中的非绝热耦合作用.     

OCS分子在128 nm附近的光解动力学研究：S(3PJ=2,1,0)、S(1D2)以及S(1S0)产物通道

本文利用时间切片离子成像技术对OCS分子进行了真空紫外波段的光解动力学研究. 在四个光解光波长(从129.32到126.08 nm)下测量了硫原子解离产物S(³P_J=2,1,0)、S(¹D₂)、S(¹S₀)的速度影像，并从中清晰地发现了四个主要的解离产物通道：S(³P_J=2,1,0)+CO(X¹Σ⁺)，S(³P_J=2,1,0)+CO(A³π)，S(¹D₂)+CO(X¹Σ⁺)和S(¹S₀)+CO(X¹Σ⁺). 在实验影像中，产物CO分子的部分振动态结构能够得到分辨. 实验还获取解离产物总平动能谱，产物分支比和角分布. 对实验结果进行分析显示除绝热解离通道S(³P_J=2,1,0)+CO(A³π)之外，在其他三个产物通道中非绝热效应都起到非常重要的作用.     

CS分子在207 nm的光解动力学研究：S(1D2)+CO(X1Σ+)产物通道

利用直流时间切片离子成像技术对OCS分子在紫外波段207 nm的光解产物S(¹D₂)进行了偏振实验研究. 通过在两种不同的共振增强多光子电离中间态，¹F₃和¹P₁, 以及四种不同的泵浦-探测激光偏振几何构型下探测了光碎片S(¹D₂)的角动量极化特性. 使用分子坐标系极化模型和实验室坐标系各向异性模型提取和分析出对应产物CO(X¹Σ⁺)的角分布.观测到的总平动能释放谱表明解离过程存在三种解离通道，分别对应于低、中、高平动能解离通道. 低、中平动能通道的来源与光解波长在较长波长下得到的双峰分布来源一致. 高平动能通道是一种新的解离通道，它来自于单重排斥态A(2¹A'')的直接解离.     

在193 nm关于Si2分子的离子解离动力学的成像研究

在193 nm的单色激光实验中,本文利用时间切片离子速度成像技术,研究了经193 nm双光子电离得到的Si₂⁺的解离反应动力学过程. 根据实验得到的Si⁺离子的速度成像,观测到了两种离子直接解离通道：Si(³P_g)+Si⁺(²P_u)和Si(¹D₂)+Si⁺(²P_u). 电子基态的Si₂分子处于v=0∽5的振动态上,其经过双光子电离后激发到Si₂⁺离子的多个电子激发态势能面,生成主要通道Si(³P_g)+Si⁺(²P_u),其中v=1的解离信号最强. 此外,由于势能曲线2²Π_g与3²Π_g相同对称性引起的避免性势能面交叉,生成次要反应通道Si(¹D₂)+Si⁺(²P_u). 通道Si(¹D₂)+Si⁺(²P_u)的产物亦可以由生成的基态Si₂⁺(X⁴Σ_g^-)吸收一个193 nm光子后解离得到,其对应产物则具有更大的动能.     

利用时间切片离子速度成像技术对AlO在193 nm的光解反应动力学研究

本文利用时间切片离子速度成像技术对AlO分子在193 nm下的光解反应动力学进行了研究. 实验通过产物Al⁺的离子速度和角度分布分析，发现了两个光解离反应通道，分别为中性AlO分子的单光子解离生成产物Al(²P_u)+O(³P_g)的通道，和AlO分子吸收两个光子电离产生AlO⁺进而解离生成产物为Al⁺(¹S_g)+O(³P_g)的反应通道. 每一个解离通道包括了AlO(v=0∽2)振动态的贡献，其中中性解离反应通道与离子解离反应通道相比，产物的各向异性参数对AlO的振动态依赖更大.     

OCS经由F 31Π里德堡态生成CO(X1Σ+)+S(1D2)产物的波长相关性光解离

本文利用时间切片离子速度成像技术在134∽140 nm波段研究了OCS分子经由F 3¹Π里德堡态的真空紫外光解离动力学. 在选取的5个分别对应OCS(F 3¹Π, v₁=0∽4)的伸缩振动激发的光解波长，实验测得了来自CO(X¹Σ⁺)+S(¹D₂)产物通道的SS(¹D₂))实验影像，并获得了总平动能谱和CO(X¹Σ⁺, v)共生产物的振动布居及角分布. 结果分析表明OCS分子解离生成CO(X¹Σ⁺)+S(¹D₂)产物的过程经历了上态F 3¹Π 与C_?v和C_s构型的下电子态间非绝热耦合过程. 实验结果显示了很强的波长相关性：OCS (F 3¹Π, v₁)的较低转动激发态(v₁=0∽2)和较高转动激发态(v₁=3, 4)的CO(X¹Σ⁺)产物的振动布居和角分布具有显著差异，表明该解离过程中具有不同的解离机理. 本结果提供了振动耦合可能对真空紫外光解离动力学产生关键作用的相关证据.     

Cl(2P)+D2→DCl+D反应中波恩-奥本海默近似有效性的交叉分子束研究

本文利用高分辨的里德堡态氘原子标识-交叉分子束装置，研究了碰撞能为4.5∽6.5 kcal/mol范围内Cl(²P)[Cl(²P_3/2)和Cl^*(²P_1/2)]与D₂的反应. 虽然自旋轨道激发态反应Cl^*(²P_1/2)+D₂在波恩-奥本海默(B-O)近似下本应是禁阻的，但实验中观测到了该反应的贡献. 通过测量靠近后向的碰撞能相关的微分散射截面连线，发现低碰撞能下的产物主要来自于B-O近似禁阻的反应Cl^*+D₂. 随着碰撞能的提高，自旋轨道基态反应Cl+D₂的反应性增加明显要比自旋轨道激发态反应Cl^*+D₂更快，并且在高碰撞能下成为产物的主要来源. 实验结果表明：在低碰撞能下，Cl^*中自旋轨道激发态的额外能量，可以帮助B-O近似禁阻的反应Cl^*+D₂越过势垒；然而当碰撞能接近和高于反应势垒时，B-O近似允许的反应Cl+D₂占主导地位. Cl/Cl^*+D₂反应中B-O近似有效性的特征与其同位素反应Cl/Cl^*+H₂是一致的.     

Br2+分子离子[1+1]双光子解离动力学

本文利用最近研制的低温离子阱-离子速度成像谱仪在冷离子束中研究了同位素质量分辨的⁷⁹Br₂⁺分子离子的[1+1]双光子激光解离动力学. 借助其1⁴Σ^-_u,3/2态为中间态使⁷⁹Br₂⁺共振吸收两个光子至4∽5 eV区域的高激发态并发生解离. 利用离子速度成像技术获得了光解产物⁷⁹Br⁺的二维速度分布和平动能释放谱. 通过平动能释放谱确定了不同解离能量处量子态分辨的解离产物通道分支比. 光碎片产物的角分布表明⁷⁹Br₂⁺分子离子的双光子解离是1⁴Σ^-_u,3/2态的ΔΩ=0平行跃迁至一个Ω=3/2高解离态发生的. 由于分子激发态中的强自旋-轨道耦合作用,高激发的四重态很可能参与到实验观测的光解过程.     

Absolute frequency measurements of the 0002-0000, 2001-0000, and 1201-0000 bands of N2O by heterodyne spectroscopy

The absolute frequencies of 39 lines in the 00⁰2-00⁰0, 20⁰1-00⁰0, and 12⁰1-00⁰0 bands of N₂O in the range 4300–4800 cm^?1 have been measured by heterodyne frequency techniques. The lines were each measured in Doppler-limited absorption, with a color-center laser as a tunable probe of the N₂O and two stabilized CO₂ lasers as reference frequencies. New rovibrational constants have been fitted to these measurements. Tables of calculated transition frequencies are given, with estimated absolute uncertainties as small as 10^?4 cm^?1. The pressure shifts of four lines have been measured, and the values fall within the range of 0 to ?2 MHz/kPa (0 to ?0.2 MHz/Torr).     

Intensities and widths of H2O lines between 1800 and 2100 cm-1

A non-linear, least-squares program was used to obtain the line intensities and widths of 91 air-broadened lines in the ν₂ rotation-vibration band of water vapor in the region from 1800 to 2100 cm^-1. The values obtained for the line intensities are, on the average, about 7% stronger than the Air Force Cambridge Research Laboratories (AFCRL) Atmospheric Absorption Line Parameters Compilation. The experimental values for the half widths of the H₂O lines are, on the average, 4% higher than the calculated AFCRL values. The measurements have confirmed the narrow widths of some high J transition lines measured by tunable diode laser spectroscopy.     

Transition densities between the 01+, 21+, 41+, 02+, 22+, 11− and 31− states in 12C derived from the three-alpha resonating-group wave functions

All the multipole transition densities between the seven T = 0 states in ¹²C are calculated with the use of the microscopic 3α resonating-group wave functions which are obtained by dynamically solving the 3α relative motion with the total antisymmetrization taken into account exactly. The observed elastic and inelastic electron scattering form factors for the transition to the 2₁⁺, 4₁⁺, 0₂⁺, 1₁^?and 3₁^? states are well reproduced with no additional effective charge. The existence of a deformed intrinsic state for the 0₁⁺, 2₁⁺and 4₁⁺states is deduced by the analysis of the transition densities between them which are derived by the weak-coupling-type 3α wave functions; the intrinsic density distribution is illustrated. The monopole density distribution of the 0₂⁺, 2₂⁺ and 1₁^?, states is found to be much longer ranged than that of the 0₁⁺, 2₁⁺ and 4₁⁺ states; the 3₁^? state case is intermediate. On the basis of the transition densities between the 0₁⁺, 2₁⁺, 0₂⁺ and 2₂⁺ states, analysis is made of the transition between the shell-like states and the molecule-like states with a large spatial-structure change. Specific, effective nucleon-nucleon interactions are folded into the transition densities here obtained. The evident dependence of the radial shape of the folded nucleon-¹²C form factors on the choice of the interactions and the multi-step form factors for the excitation of the 0₂⁺, 1₁^? and 3₁^? states are discussed.     

Heterodyne frequency measurements on N2O between 1257 and 1340 cm−1

Frequency measurements are given for the 00⁰1-00⁰0 and 01¹1-01¹0 bands of N₂O from 1257 to 1340 cm^?1. The measurements utilize heterodyne techniques by measuring small frequency differences between a tunable diode laser locked to the center of an N₂O absorption line and harmonic combinations of frequencies of radiation from two CO₂ Lamb-dip-stabilized lasers. The measurements are facilitated by the use of the CO laser as a transfer laser whose frequency is also measured. These measurements have been combined with other data to provide new band constants and frequency calibration tables for several band systems of N₂O in the following regions; 1215 to 1340, 1816 to 1930, and 2135 to 2268 cm^?1. A correction factor is also provided for existing calibration tables near 590 cm^?1.     

High-resolution study of E0 internal pair decay of excited 0+ states in 58,60,62Ni

The recently developed magnetic plus Si(Li)-Si(Li) sum-coincidence technique is employed to measure E0 internal-pair-formation (IPF) branching ratios of excited 0⁺ states in ^58,60,62Ni. The $\text{X(}\text{E}\text{0}\text{E}\text{2}\text{)}$ values are obtained for a new 0⁺₄ state in ⁶⁰Ni at 3588.0 keV, for the 0⁺₂ and 0⁺₃ states at 2942.3 keV and 3530.9 keV in ⁵⁸Ni, for the corresponding states at 2284.8 keV and 3318.3 keV in ⁶⁰Ni, and for the 0⁺₂ state in ⁶²Ni at 2048.4 keV. The results are combined with the available lifetimes of these states to extract the monopole strengths ?²(0⁺_i ? 0⁺₁). The results and the nature of the 0⁺ states are discussed.     

Determination of the lifetime of the mercury 63P1 state

A pulsed tunable dye laser was used for a high resolution experimental study of mercury fluorescence from the 6³P₁ state. The output of the dye laser was frequency doubled into the 253.7 nm region using a potassium penta-borate crystal. Exponential decays were observed for each of the five individual components of the hyperfine structure separately and the effects of the trapping of resonance radiation on the observed lifetime of the 6³P₁ state of mercury were investigated for each resolvable component. Within experimental error, the natural radiative lifetime of the 6³P₁ state was found to be independent of the hyperfine component irradiated and a value of 122±2 nsec was obtained, consistent with results found by other methods.     

Laser-induced fluorescence and microwave-optical double-resonance study of the B1Σ+-X1Σ+ system of magnesium monoxide

Doppler-limited, laser-induced fluorescence spectra on the B¹Σ⁺-X¹Σ⁺ (v′ = v″ = 0 and 1) system of MgO have been obtained. The results of the optical analysis were merged with our microwave-optical double-resonance measurements to produce the following set of spectroscopic parameters for the B and X states, where the units are in cm^?1, and the uncertainties represent 95% confidence limits: T′_0.0 = 20003.594(2); B′₀ = 0.58004(3); D′₀ = 1.13(2) × 10^?6; B″₀ = 0.57198(3); D″₀ = 1.20(2) × 10⁶; T′_1.1 = 20043.423(2); B′₁ = 0.57528(4); D′₁ = 1.14(11) × 10⁶; B″₁ = 0.56674(4); D″₁ = 1.22(10) × 10⁶.     

15N216O在1650-3450 cm-1的高分辨红外光谱

采用傅里叶变换红外光谱仪记录了富含¹⁵N₂¹⁶O同位素的一氧化二氮样品在1650-3450 cm^-1波段的高分辨振转光谱,得到了该同位素分子超过7300吸收谱线位置的实验值,经分析实验精确度好于5.0×10^-4 cm^-1. 基于有效哈密顿量模型预测和带带转动分析,确定了所有吸收线的归属;获得了29个新吸收带的振转光谱参数,并优化了其他44个吸收带的光谱参数值. 并且发现有效哈     

Intensity of CO2 bands in the 4.8- to 5.3-μm region. The (1110,0310)II-0000 band

Measurements of the line strengths of the (11¹0,03¹0)_II-00⁰0 band of CO₂ (1932.466 cm^?1) have been made with high resolution. They exhibit a strong Coriolis interaction which enhances the P-branch intensity while reducing that of the R branch. The rotationless dipole moment of the transition and the ξ-constant representing this interaction have been determined as: R(0) = (6.57 ± 0.03) × 10^?4D, ξ = ?0.0598 ± 0.0002.     

The forgotten 1D2 level of charmonium

The standard “charmonium” picture predicts four C=+1 states (³P₀, ³P₁, ³P₂, 2 ¹S₀) between ψ and ψ′. If these are identified with the four experimentally observed levels, serious difficulties arise. We remark that a ,,forgotten” ¹D₂ level (J^PC=2^?) is likely to be around 3.5 GeV. It may be identified with χ(2.45) or χ(3.50), avoiding the above above difficulties. The 2 ¹S₀ level has then yet to be discovered.