CO分子的A^1Π（v=1）对d^3△（v=5）态的微扰研究

CO谱带的微扰给谱线的标识和分析带来挑战.这里针对CO A1Ⅱ(v=1)对d3△(v=5)态的徵扰,首先采用有效哈密顿矩阵的方法重新分析了d3△-a3Ⅱ(5,0)带高精度的涉及d3△2和d3△3的振转光谱数据,发现A1Ⅱ的微扰可忽略不计.进一步理论计算了由A1Ⅱ的微扰产生的d3△的△1,△2和△3的转动能级移动扣d3△-a3Ⅱ(5,0)光谱强度的变化.发现△1的能级移动最大,最大可达4 cm-1,这个能级移动随J值的增大而减小;对△2和△3的影响在J小时可忽略不计.光谱强度的改变有类似的变化趋势,涉及到△1的d3△1-a3Ⅱ光谱强度减小量最大可达20%,随J的增大,此减小量变小;对涉及△2和△3的光谱强度此微扰可忽略不计,从而给出了上面实验数据分析中不考虑微扰的原因.     

CO分子的A1Π(v=1)对d3∆(v=5)态的微扰研究

CO谱带的微扰给谱线的标识和分析带来挑战.这里针对CO A1Π(v=1)对d3∆(v=5)态的微扰,首先采用有效哈密顿矩阵的方法重新分析了d3∆—a3Π(5,0)带高精度的涉及d3∆2和d3∆3的振转光谱数据,发现A1Π的微扰可忽略不计.进一步理论计算了由A1Π的微扰产生的d3∆的∆1,∆2和∆3的转动能级移动和d3∆—a3Π(5,0)光谱强度的变化.发现∆1的能级移动最大,最大可达4 cm-1,这个能级移动随J值的增大而减小;对∆2和∆3的影响在J小时可忽略不计.光谱强度的改变有类似的变化趋势,涉及到∆1的d3∆1—a3Π光谱强度减小量最大可达20%,随J的增大,此减小量变小;对涉及∆2和∆3的光谱强度此微扰可忽略不计,从而给出了上面实验数据分析中不考虑微扰的原因.     

激发态H2(X1∑+g,v=1,J=1)之间的碰撞能量合并

受激拉曼激发H2(0,1)基态的Q支得到H2(1,1)能级.在室温条件下,利用反斯托克斯拉曼散射(CARS)探测技术测量了碰撞能量合并(EP)过程H2(1,1)+H2(1,1)→H2(2,J)+H2(0,J″)及H2(1,1)与H2(1,J)转动能级间的碰撞转移速率系数.扫描CARS谱表明在H2(1,1)能级的碰撞能量...     

如何让学生学会使用公式1/u+1/v=1/F

公式1/u+1/v=1/F是几何光学中的基本方程之一。公式本身虽然简单,易懂易记,但学生使用这个公式算题的时候,却不是没有困难的,他们常把各个量的符号弄错,因而得不出正确的结果。由于这种原因,我在教学中对使用这个公式算题时应该注意那几点,作了如下的说明:     

High resolution FTIR spectra of AsD3 in the 20-1000 cm−1 region. The ground, 98, v2 = 1 and v4 = 1 states

The pure rotational spectrum of the near-spherical oblate symmetric top AsD₃ has been recorded in the 20–120cm^?′ region with a resolution of 2.3 × 10^?3 m^?1 employing an FT interferometer. Rotational transitions with 5 ? J ? 29 and 0 ? X ? 25 of the ground state (GS) and the v₂ = 1 and v₄ = 1 excited states have been assigned. Splittings were observed for the GS, 98, K = 3 and 6 levels, the K = 3 levels of v₂ and the kl = ?2, 1, 4 and 7 levels of v₄. Furthermore the x,y Coriolis coupled v₂ and v₄ bands, v ⁰ ₂ = 654.4149cm^?1, and v ⁰ ₄ = 714.3399 cm^?1, have been examined with a resolution of 2.4 × 10^?3 cm^?1, and ca. 2500 allowed and 336 ‘forbidden’ lines with J′_max = 31 and K′_max = 28 have been assigned. Appropriately weighted GS data comprising FIR lines, allowed and ‘forbidden’ (up to ΔK = ±6) GS combination differences, mmw data, and ΔJ = 0, ΔK = ±1 distortion moment transitions were fitted together, and GS parameters complete through H parameters have been determined. Two different reductions of the Hamiltonian, either with ΔK = ±6 (h₃) or ΔK = ±3 (ε) off-diagonal elements, have been employed. Equivalence of these reductions up to J = 22 was established while for J > 22 the ε reduction is superior. The v₂ and v₄ data have been fitted with two equivalent models based on different reductions of the rovibrational Hamiltonian. In addition to the dominating x,y Coriolis resonance, ζ ^y ₂₄ 0.520, Δ(k ? l) = ±3 and ±6 interactions are important and were accounted for by the models. The transition moment ratio |M₄: M₂| =0.75 has been determined, with a positive sign of the product M ₂ζ ^y ₂₄ M ₄. An improved r₀ structure, r₀(AsD) = 1.51753 Å and α₀(DAsD) = 92.000°, has been determined.     

Rotational analysis of the v 2 + v 6 ±1, v 5 ∓1 + v 6 ∓1 and v 5 ∓1 + v 6 ±1 interacting infrared bands of methyl bromide

The rotational analysis of the infrared absorption spectrum of CH₃ ⁷⁹Br and CH₃ ⁸¹Br between 2150 and 2510 cm^-1 was performed on a Fourier transform spectrum with a resolution of 0·007 cm^-1. The bands v ₂ + v ₆(E) and v ₅ + v ₆(A ₁ + A ₂ + E) occur in this region, giving rise to several perturbations as in the corresponding system of methyl chloride [3]. Forbidden transitions, observed in correspondence of the level crossing of the x-y Coriolis coupling between v ₂ + v ₆ and v ₅ + v ₆(E), enabled us to estimate the value of A″ - 225D″_K at 5·16186 cm^-1 for CH₃ ⁷⁹Br and 5·16173 cm^-1 for CH₃ ⁸¹Br. The parallel system of v ₅ + v ₆ exhibits a perpendicular structure, and an l-type resonance couples those levels of the parallel and perpendicular components of v ₅ + v ₆ involved in transitions from the K″ = 0 levels of the ground state. The ^QQ ₀ branches of the A ₂ component of v ₅ + v ₆, made active by this resonance, are observed for both isotopic species.     

The stereodynamic properties of the F + HO (v,j)→HF + O reaction on the 1A' and 3A' potential energy surfaces by quasi-classical trajectory: Initial excitation effect (v =1-3, j = 0 and v = 0, j =1-3)

The stereodynamic properties of the F + HO (v, j) reaction are explored by quasi-classical trajectory (QCT) calculations performed on the ¹A' and ³A' potential energy surfaces (PESs). Based on the polarization-dependent differential cross sections (PDDCSs) and the angular distributions of the product angular momentum with the reactant at different values of initial v or j, the results show that the product scattering and product polarization have strong links with initial vibrational-rotational numbers of v and j. The significant manifestation of the normal DCSs is that the forward scattering gradually becomes predominant with the initial vibrational excitation increasing, and the scattering angle of the HF product taking place on the ³A' potential energy surface is found to be more sensitive to the initial value of v. The product orientation and alignment are strongly dependent on the initial rovibrational excitation effect. With enhancement in the initial rovibrational excitation effect, there is an overall decrease in the product orientation as well as in the product alignment either perpendicular to the reagent relative velocity vector k or along the direction of the y axis, for which the initial rotational excitation effect is much more noticeable than the vibrational excitation effect. Moreover, the initial rovibrational excitation effect on the product polarization is more pronounced for the ³A' potential energy surface than for the ¹A' potential energy surface.     

The stereodynamic properties of the F+HO(v,j) → HF+O reaction on~1 A' and ~3A' potential energy surfaces by quasi-classical trajectory calculations:Initial excitation effect(v=1-3, j=0 and v= 0, j=1-3)

The stereodynamic properties of the F ＋ HO （v, j） reaction are explored by quasi-classical trajectory （QCT） calculations performed on the 1At and 3At potential energy surfaces （PESs）. Based on the polarization-dependent differential cross sections （PDDCSs） and the angular distributions of the product angular momentum with the reactant at different values of initial v or j, the results show that the product scattering and product polarization have strong links with initial vibrationalrotational numbers of v and j. The significant manifestation of the normal DCSs is that the forward scattering gradually becomes predominant with the initial vibrational excitation increasing, and the scattering angle of the HF product taking place on the 3At potential energy surface is found to be more sensitive to the initial value of v. The product orientation and alignment are strongly dependent on the initial rovibrational excitation effect. With enhancement in the initial rovibrational excitation effect, there is an overall decrease in the product orientation as well as in the product alignment either perpendicular to the reagent relative velocity vector k or along the direction of the y axis, for which the initial rotational excitation effect is much more noticeable than the vibrational excitation effect. Moreover, the initial rovibrational excitation effect on the product polarization is more pronounced for the 3At potential energy surface than for the 1At potential energy surface.     

Recent progress with the CO-overtone Δv=2 laser

We report the recent progress in the performance of the CO-overtone v=2 laser. We were able to increase both the number of lines and the output power by a significant amount. This laser is now a reliable source for spectroscopic applications in the spectral region from 2500–3800 cm^–1. The typical parameters of the laser plasma and a table with the observed laser transitions and their frequencies are given.     

动生电动势E=Bιv的教学

动生电动势E=Bιv在高考中一直是重点、热点,常考不歇。学生对于这一点总是理解不透,应用不活。如何才能让学生更好地把握这一考点,笔者在教研过程中做了一些探讨。总结出先实验体会,后理论推导,再进行公式中字母含义的理解,最后用题目训练的教学设计。一实验演示如图1所示,当闭合导体回路的一部分作切割磁     

vt=v0＋at规律的实验研究

匀变速直线运动的速度规律vt=v0+at是高中物理必修课本第一册第二章第七节的内容,是本章的重点之一.但教材仅提供文字性材料,没有安排演示实验,在实际教学中往往是由加速度a的定义公式来导出速度规律,偏重公式的应用与掌握,忽视物理思想和物理方法的教育.至今,在专业刊物上也没有文章介绍过有关研究匀加速直线运动速度规律的演示实验,为此我们考虑在学生已经学过<练习使用打点计时器>的情况下,用打点计时器通过纸带记录小车运动并对所打的点进行研究得出速度公式vt=v0+at,进而得到速度图象.这样使学生更具真实感,表象更清晰,同时渗透了创新教育和重要的物理思想和物理方法的教育.下面介绍我们设计的演示实验,供同行参考.     

交叉分子束实验研究F+D_2(v=1,j=0)反应（英文）

本文使用交叉分子束方法研究了氟原子和振动激发态氖分子D_2(v=1,j=0)的反应.使用受激拉曼抽运的方法制备了振动激发的D_2分子.实验中未观测到来自于旋轨耦合激发态氟原子F*(~2P_(1/2))与振动激发态D_2分子的贡献.观测到来自于旋轨耦合基态氟原子F(~2P_(3/2))和振动激发态D_2的反应信号,相应的产物DF分子布居于u'=2,3,4,5振动态上.与振动基态反应F+D_2(v=1,j=0)相比,振动激发态反应F+D_2(v=1,j=0)生成的DF产物转动分布更"热".获得了振动激发反应的四个碰撞能在0.32至2.62 kcal/mol范围内的微分反应截面.在最低的碰撞能0.32 kcal/mol下,所有振动态的DF产物都以后向散射为主.随着碰撞能的增加,DF产物的角分布逐渐从后向转移到侧向.测量了DF(v'=5)产物的前向微分散射截面随碰撞能变化的曲线.前向散射的DF(v'=5)信号出现于1.0 kcal/mol.在2.62 kcal/mol碰撞能下DF(v'=5)主要为前向散射.     

Observation of the v′=8←v=0 vibrational overtone in cold trapped HD+

We report the observation of the hitherto undetected v′=8←v=0 vibrational overtone in trapped HD⁺ molecular ions, sympathetically cooled by laser-cooled Be⁺ ions. The overtone is excited using 782 nm laser radiation, after which HD⁺ ions in v=8 are photodissociated by the 313 nm laser used for Be⁺ cooling. The concomitant loss of HD⁺ is detected by the method of secular excitation (Roth et al. in Phys. Rev. A. 74:040501(R), 2006). We furthermore present details of the experimental setup, and we show that results from spectroscopy of v′=8←v=0 overtones in combination with accurate ab initio calculations may yield a new value for the proton–electron mass ratio with an accuracy of order 1 ppb.     

Na2(A1∑u+,v=8～b3Ⅱ0u,v=14)-Na体系转动传能的碰撞量子干涉效应

沙国河及其工作组于1995年发表了CO A1Π(v=0)～e3∑-(v=1)与He1,Ne及其它碰撞伴的碰撞过程中转动传能的碰撞量子干涉现象,并得到了积分干涉角,陈等从理论和实验上发现了Na2(A1∑u ,v=8～b3Π0u,v=14)体系与Na(3s)碰撞的碰撞量子干涉现象,孙等计算了其积分干涉角,但是对微分干涉角没有过多的计算.本文作为对原子-双原子体系碰撞诱导转动传能的进一步理论研究,在含时一级波恩近似的基础上考虑各向异性相互作用势和长程相互作用势,计算了单叁混合态的Na2(A1∑u ,v=8-bΠ0u,v=14)体系与Na碰撞的微分干涉角,并得到了微分干涉角与碰撞参数的关系,此理论模型对理解和进行分子束实验是非常重要的.     

Na2(A1∑+u，v=8~b3Π0u，v=14)-Na体系碰撞诱导转动传能的微分干涉角

对原子-双原子体系碰撞诱导转动传能进行了进一步的理论研 究. 在含时一级波恩近似的基础上考虑各向异性相互作用势，计算了 单-叁重混合态的Na2(A1∑+u，v=8~b3Π0u，v=14)体系与Na碰撞 的微分干涉角(b·?和b??)，得到了微分干涉角与碰撞参数的关系，对 其碰撞量子干涉作出了定量准确的描述.     

The characteristics of O＋HD （v = 0, j = 0） reaction dynamics

The analytical potential energy function of HDO is constructed at first using the many-body expansion method.The reaction dynamics of O+HD(v = 0,j = 0) in five product channels are all studied by quasi-classical trajectory(QCT) method.The results show that the long-lived complex compound HDO is the dominant product at low collision energy.With increasing collision energy,O+HD → OH+D and O+HD → OD+H exchange reactions will occur with remarkable characteristics,such as near threshold energies,different reaction probabilities,and different reaction cross sections,implying the isotopic effect between H and D.With further increasing collision energy(e.g.,up to 502.08 kJ/mol),O+HD → O+H+D will occur and induce the complete dissociation into single O,H,and D atoms.     

Cl+CHD3(v1=1)反应中的成对动态学:侦测激光波长的效应

用交叉分子束试验探讨氯原子与C?H 键激发的CHD3化学反应，并用(2+1)共振多光子电离及离子影像法来侦测CD3基态生成物．发现所得的影像对电离光子的波长极为敏感．这表明，与基态反应比较，C?H激发反应较易产生转动激发的CD3．实验结果也证明CD3D的转动与HCl的振动激发有相反的关联性．     

RbH(X1∑+,v=O～2)能级与H2碰撞振动能量转移

利用积分时间分辨荧光光谱方法,研究了RbH(X1∑+,v=0～2)与H2间的振动碰撞能量转移.在Rb-H2混合样品池中,泵浦激光双光子激发Rb原子至6D态,Rb(6D)与H2反应生成RbH(x1∑+)分子,探测激光延迟泵浦激光20 ns,通过激光感应荧光光谱(LIF)的测量,确定了X1∑+(v=0～2,J)原生态的转动...     

单三重混合态Na2 (A1Σu+, v=8 ~ b3Π0u, v=14)和Na 碰撞传能的干涉相位角的计算

文章详细介绍了单三重混合态同核双原子分子Na2 (A1Σu+, v=8 ~ b3Π0u, v=14)和Na碰撞传能的干涉相位角的理论计算方法.并且采用了两种不同的相互作用势（一种是长程吸引相互作用势,另一种是Lennard-Jones 相互作用势）,进行了具体的数值计算.在实验温度750K下,计算积分干涉相位角,与实验值相差很小.干涉相位角的大小表明混合态体系碰撞传能中的量子干涉效应是不容忽视的.最后,分析了干涉相位角随着不同参数的变化关系,发现Na2 – Na体系中,干涉相位角随各参数变化而变化,但变化不大.     

RbH(X1∑+,v=O～2)能级与H2碰撞振动能量转移

利用积分时间分辨荧光光谱方法,研究了RbH(X1Σ+,v=0～2)与H2间的振动碰撞能量转移。在Rb-H2混合样品池中,泵浦激光双光子激发Rb原子至6D态,Rb(6D)与H2反应生成RbH(X1Σ+)分子,探测激光延迟泵浦激光20ns,通过激光感应荧光光谱(LIF)的测量,确定了X1Σ+(v=0～2,J)原生态的转动布居分布。增加检测激光与泵浦激光的延迟时间,测量了0～10μs延迟时间内各振动态时间分辨LIF强度,v=0,1能级荧光信号先增加后缓慢减弱,这是因为RbH在瞬间形成后通过碰撞转移和扩散而减少所致。通过速率方程分析,并利用振动能级上布居数变化与积分时间分辨荧光强度的关系,得到v=1→v=0和v=2→v=1的碰撞转移速率系数分别为(2.8±0.6)×10-11cm3·s-1和(3.4±0.8)×10-11cm3·s-1。而v=0,1,2的扩散率分别为(4.9±1.1)×105,(1.0±0.3)×105,(0.6±0.2)×105s-1。实验表明,v=2能级上布居数衰减率最大。