Coherence and correlation parameters for thed 3 Π u − (v=0,1,2,3;N=1) states of H2

We have applied the density matrix formalism and the distorted-wave approximation to calculate the Stokes parameters for thed ³ Π _u ^? (v=0,1,2,3;N=1) states of H₂ excited from the X¹ ∑ _g ⁺ (v=0,N=1) state by electron impact at the incident energies ranging from 15 to 40 eV. Our results show that these parameters are nearly independent of the vibrational quantum number of the excited states. However, the polarization of the radiation emitted by the target in the subsequent decay process increases with increasing incident energies.     

Renner-Teller and Fermi resonance interactions for the v3=1 and v7=2 vibronic levels in the A2Πu and X2Πg electronic states of HC4H+

The excitation of the v(3) = 1 (σ(g)(+) C-C stretch) and the v(7) = 2 (π(g)(2) C≡C-C bend) modes in the A(2)Π(u) electronic state of diacetylene cations results in Renner-Teller (R-T) and Fermi interactions. The 3(0)(1) and 7(0)(2) vibronic bands in the A(2)Π(u)-X(2)Π(g) transition of HC(4)H(+) have been measured with rotational resolution using cavity ringdown spectroscopy in a supersonic slit jet discharge. The analysis yields T(00) = 20520.828(4) cm(-1), B' = 0.14047(2) cm(-1), and A' = -17.95(1) cm(-1) for the v(3) = 1 and T(00) = 20573.659(4) cm(-1), B' = 0.14018(3) cm(-1), and A' = -11.55(1) cm(-1) for the v(7) = 2 level in the A(2)Π(u) electronic state. A vibronic analysis has been carried out taking into consideration the R-T, spin-orbit, and Fermi resonance interactions between the ν(3) and ν(7) modes. The levels are fitted to the eigenvalues of an appropriate Hamiltonian matrix. This yields the vibrational frequencies ω(3)′ = 811.8 cm(-1) and ω(7)′ = 403.2 cm(-1), Renner parameter ε(7)′ = 0.065, Fermi coefficients W(1)′ = 10.3 cm(-1) and W(2)′ = 5.1 cm(-1), and spin-orbit interaction constant A(SO)′ = -31.1 cm(-1). A corresponding R-T analysis has been carried out for the X(2)Π(g) ground state of HC(4)H(+) using data available in the literature [Callomon, J. H. Can. J. Phys. 1956, 34, 1046]. This gives ω(3)" = 956.2 cm(-1), ω(7)" = 435.4 cm(-1), ε(7)" = 0.028, W(1)" = 7.2 cm(-1), W(2)" = 10.9 cm(-1), and A(SO)" = -33.3 cm(-1).     

Experimental verification of strong rotational dependence of fluorescence and predissociation yield in the b1Πu(v = 1) level of 14N2

New, rotationally resolved fluorescence-excitation spectra confirm coupled-channel Schro?dinger-equation predictions of strong rotational dependence of the fluorescence and predissociation yields in the b(v = 1) level of (14)N(2).     

Scattering Resonance States and Partial Potential Energy Surface of Reaction I ＋ HI （ v = 0 ） → IH （ v＇ = 0 ） ＋ I

The partial potential energy surface of the I ＋ HI →IH ＋ I reaction involving the translational and vibrational motions has been constructed at the QCISD（ T ）//MP4SDQ level with the pseudo potential method that is helpful to interpreting the scattering resonance states. The lifetimes of the scattering resonance states in the title reaction obtained from the partial potential energy surface are about 90-120 fs, which agrees with the result of high-resolved threshold photodetachment spectroscopy of anion IHI^- measured by Neumark.     

I+HI(v=0)→IH(v′=0)+I体系散射共振态的理论研究

在 QCISD ( T) / / MP2水平下 ,分别采用 6-3 1 1 ++G* * 基组和 SDD基组对重 -轻 -重反应 I+HI(ν=0 )→ IH(ν′=0 ) +I中的 H和 I的偏分势能面进行了 ab initio计算 ,指认出在 0～ 0 .5 8e V碰撞能范围内所产生的 6个散射共振态为 Feshbach共振 ,并与文献报道的量子散射理论计算与高分辨阈值光分离光谱实验结果进行了比较 .     

Collision induced absorption in the a1Δ(v = 2) ← X3Σg(-)(v = 0) band of molecular oxygen

Using cavity ring-down spectroscopy we measured the collision induced absorption spectrum associated with the a(1)Δ(v = 2) ←X(3)Σ(g)(-)(v = 0) band of oxygen near 922 nm both in pure oxygen and in mixtures of oxygen and nitrogen. For pure oxygen, we report for this band an integrated absorption of (1.56 - 0.04/+0.40) × 10(-5) cm(-2) amg(-2). We find that collisions between oxygen and nitrogen do not result in any measurable CIA signal. At 1 bar of oxygen, this collision induced transition is much stronger than the allowed magnetic dipole and electric quadrupole transitions.     

The polarization dependent differential cross sections of the reactions:H+LiH~+(v=0,j=0)→H_2+Li~+ and H~++ LiH(v=0,j=0)→H_2~++Li

<正>Quasi-classical trajectory(QCT) calculations have been carried out to study the generalized polarization dependent differentialcross sections(PDDCSs) for the reactions H + LiH~+(v = 0,j = 0)→H_2 + Li~+ and H~+ + LiH(v = 0,j = 0)→H_2~+ + Li occurring onthe two lowest-lying electronic states of the LiH_2~+ system,using the ab initio potential energy surfaces(PESs) of Martinazzo et al.[3].Four PDDCSs,i.e.,(2π/σ)(dσ_(00)/dω_t),(2π/σ)(dσ_(20)/dω_t),(2π/σ)(dσ_(22+)/dω_t),(2π/σ)(dσ_(21-)/dω_t) have been discussed in detail.     

Steric Effects in the Cl＋CHD3（v1=1） Reaction

A recent study has revealed a full 3-dimentional reactive scattering picture of the reaction CI＋CHD3（v1=1） as the C1 atoms attack CHD3 from various directions respective to the C-H stretching bond. The reported polarization-dependent differential cross sections provide the most detailed characterization of the influences of reagent alignments on reactivity. To convey the stereo-specific information more accessible to general chemists, we show here, by proper symmetry considerations, how to retrieve from the measurements the relative integral and differential cross sections of two most common collision geometries： the end-on versus side-on attacks. The results, albeit coarse-grained, provide an appealing picture that not only reinforces our intuition about chemical reactivity, but also sheds more light on the conventional （unpolarized） attributes.     

准经典轨线研究Li+HF(v=0,j=O)→LiF+H反应动力学

基于Aguado等人拟合的APW势能面(PES),运用准经典轨线(QCT)方法,对反应Li+HF(v=0,j=0)→LiF+H的动力学性质进行了计算.主要研究了不同碰撞能条件下的反应截面、转动取向、产物散射角分布和竞争反应模式等.结果表明,该反应存在直接提取型和间接插入型两种反应模式,在低能量下反应以间接插入反应模式为主,能量大于200 meV时则以直接提取反应为主.     

Computation of cross sections for the F+H2(v=0,j=0) → FH(v′j)+H reaction by the hyperspherical method

Summary A quantum mechanical calculation of cross sections for the reaction F+H₂(v=0,j=0) FH(vj)+H has been performed on the T5A semiempirical potential surface using hyperspherical coordinates. State-to-state integral and differential cross sections converge rapidly with the number of components of the total angular momentum projection onto the axis of least inertia. Thev=3 differential cross section has a forward peak whose magnitude increases with energy whereas thev=2 differential cross section has a backward maximum, in qualitative agreement with cross-beam experiments. Thev=2 andv=3 rotational distributions are in rather good agreement with experiment, but not the vibrational branching ratios.     

H+H2(v=0,1)→H2(v′)+H反应截面的电子非绝热三维量子散射近似计算

本文把电子非绝热一维量子散射反应几率和三维量子散射反应截面的近似公式结合起来, 对于反应物分子(H_2)不同的量子振动态(v=0, 1) 分别计算了H+H_2(v=0)→H_2(v′=0, 1)+H和H+H_2(v=1)→H_2(v′=0, 1)+H的平均反应截面σ_0和σ_1, 并同文献上用电子绝热理论计算的结果作了比较, 表明对这类中性原予-分子反应碰撞的过程, 特别是当反应物分子处于振动激发态时, 电子非绝热效应是存在的。     

Semiclassical glory analyses in the time domain for the H + D2(v(i) = 0, j(i) = 0) → HD(v(f) = 3, j(f) = 0) + D reaction

We make the first application of semiclassical (SC) techniques to the plane-wavepacket formulation of time-domain (T-domain) scattering. The angular scattering of the state-to-state reaction, H + D(2)(v(i) = 0, j(i) = 0) → HD(v(f) = 3, j(f) = 0) + D, is analysed, where v and j are vibrational and rotational quantum numbers, respectively. It is proved that the forward-angle scattering in the T-domain, which arises from a delayed mechanism, is an example of a glory. The SC techniques used in the T-domain are: An integral transitional approximation, a semiclassical transitional approximation, a uniform semiclassical approximation (USA), a primitive semiclassical approximation and a classical semiclassical approximation. Nearside-farside (NF) scattering theory is also employed, both partial wave and SC, since a NF analysis provides valuable insights into oscillatory structures present in the full scattering pattern. In addition, we incorporate techniques into the SC theory called "one linear fit" and "two linear fits", which allow the derivative of the quantum deflection function, Θ?(')(J), to be estimated when Θ?J exhibits undulations as a function of J, the total angular momentum variable. The input to our SC analyses is numerical scattering (S) matrix data, calculated from accurate quantum collisional calculations for the Boothroyd-Keogh-Martin-Peterson potential energy surface No. 2, in the energy domain (E-domain), from which accurate S matrix elements in the T-domain are generated. In the E-domain, we introduce a new technique, called "T-to-E domain SC analysis." It half-Fourier transforms the E-domain accurate quantum scattering amplitude to the T-domain, where we carry out a SC analysis; this is followed by an inverse half-Fourier transform of the T-domain SC scattering amplitude back to the E-domain. We demonstrate that T-to-E USA differential cross sections (DCSs) agree well with exact quantum DCSs at forward angles, for energies where a direct USA analysis in the E-domain fails.     

Scattering Resonance States and Partial Potential Energy Surface of Reaction I+HI(v=0)→IH(v′=0)+I

The partial potential energy surface of the I HI→IH I reaction involving the translational and vibrational motions has been constructed at the QCISD(T)//MP4SDQ level with the pseudo potential method that is helpful to interpreting the scattering resonance states. The lifetimes of the scattering resonance states in the title reaction obtained from the partial potential energy surface are about 90-120 fs, which agrees with the result of high-resolved threshold photodetachment spectroscopy of anion IHI- measured by Neumark.     

He2分子b3∏g(v=9)态的预解离

The predissociation of the v=9 level in the b³Π_g state by the c³∑_g⁺ state of helium eximer(He₂) was studied based on the newly observed (9, 3) band in the b³Π_g-a³∑_u⁺ system inthe region of 12065～12445 cm^-1 employing optical heterodyne-concentration modulationabsorption spectroscopy. With the help of the previous potential energy curves and molecular constants of He₂, the corresponding predissociation mechanism for the b³Π_g (v=9) state was analyzed. An RKR potential energy curve of b³Π_g and an ab initio potential curve of c³∑_g⁺ were used to calculate the predissociation linewidths that show basic agreement withobservations, which can quantitatively explain the experiments.     

亚稳态SO(c1Σ－,v’=0)的猝灭动力学

在流动余辉装置上, 研究了SO(c¹Σ^－)的猝灭动力学过程. 获得了SO₂, O₂, CO₂, N₂, He, CS₂, CH₃OH, C₂H₅OH, C₃H₇OH, C₄H₉OH, CH₃COCH₃, C₆H₆, CH₂Cl₂, CH₂Br₂, CHCl₃, CCl₄等16种分子与SO(c¹Σ^－)发生猝灭反应的速率常数. 初步分析表明: 醇类分子C_nH_2n+1OH(n=1, 2, 3, 4)中的C—H键的数目与其对SO(c¹Σ^－)的猝灭速率成正比; CO₂, N₂等非极性无机小分子对SO(c¹Σ^－)的猝灭作用不明显, 强极性分子SO₂对SO(c¹Σ^－)的猝灭作用较强. 卤代烷烃中的卤素原子的大小对SO(c¹Σ^－)的猝灭过程发挥着较重要的作用; 而氯代烷烃中氯原子的个数与猝灭速率之间的关系不明显.     

Scattering Resonance States and Partial Potential Energy Surface of Reaction I+HI(v=0)→IH(v′=0) +I

Introduction Scattering resonance states in chemical reactionsattract much interest of both theorists and experimental-ists because the rate of a chemical reaction, state distri-bution and space distribution of the products are con-trolled by those states[1]. Scattering resonance states,also called quasi-bound states, are formed in theprocesses of energy transitions, such as collision andray radiation processes. Those states are very closelyrelated to the structure and spectroscopy of the tran…     

转动传能中的量子干涉: 干涉角和相对速度的关系

考虑一级含时波恩近似和长程相互作用势, Sun提出了转动传能中的量子干涉模型.在静态池中CO A1Π～ e 3Σ-和He碰撞的实验已经成功模拟.为了从实验中直接获得碰撞速度和干涉角的关系, Sha提出了利用分子束和离子速度成像技术的实验.作为理论研究干涉角和碰撞速度的关系,计算了不同速度下的干涉角,同时获得了变化的趋势.对在分子束条件下(通过控制碰撞速度来控制干涉角)实验具有指导意义.     

Scattering Resonance State of Br＋HBr（v=0）→BrH（v＇=0）＋Br Reaction Explored by Partial Potential Energy Surface Method

The partial potential energy surface（PPES） of Br＋HBr（v=0）→BrH（v＇=0）＋Br was designed by coupling the vibration energy and the minimum energy of the corresponding reaction path, Vmep. All the calculations were performed at the theoritical level of QCISD（T）/6-311＋＋G＊＊//MP2/6-31 1＋＋G＊＊. Based on the analysis of PPES, the dynamic ＂Eyring Lake＂ mechanism gave birth to the scattering resonance state. The resonance energy was also obtained via PPES. Then a lifetime matrix of the resonance state was established by solving the translational wave-function via the numerical propagation method. Then the reaction resonance lifetime was calculated to be 125 fs. It is in good agreement with the experimental result.     

Angular scattering using parameterized S matrix elements for the H + D2(v(i) = 0, j(i) = 0) → HD(v(f) = 3, j(f) = 0) + D reaction: an example of Heisenberg's S matrix programme

A neglected topic in the theory of reactive scattering is the use of parameterized scattering (S) matrix elements to calculate differential cross sections (DCSs). We construct four simple parameterizations, whose moduli are smooth step-functions and whose phases are quadratic functions of the total angular momentum quantum number. Application is made to forward glory scattering in the DCS of the H + D(2)(v(i) = 0, j(i) = 0) → HD(v(f) = 3, j(f) = 0) + D reaction at a translational energy of 1.81 eV, where v and j are vibrational and rotational quantum numbers respectively. The parameterized S matrix elements can reproduce the forward scattering for centre-of-mass reactive scattering angles up to 30° and can identify the total angular momenta (equivalently, impact parameters) that contribute to the glory. The theoretical techniques employed to analyze structure in the DCS include: nearside-farside theory, local angular momentum theory--in both cases incorporating resummations of the partial wave series representation of the scattering amplitude--and the uniform semiclassical theory of forward glory scattering. Our approach is an example of Heisenberg's S matrix programme, in which no potential energy surface is used. Our calculations for the DCS using the four parameterized S matrix elements are counterexamples to the following universal statements often found in the chemical physics literature: "every molecular scattering investigation needs detailed information about the interaction potential," and "an accurate potential energy surface is an essential element in carrying out simulations of a chemical reaction". Both these statements are false.