MJ and collision energy dependent attenuation of Rg (3P2) by CF3Br

The total attenuation cross-section of Rg (³P₂) (Rg = Ar, Kr) by the collision with CF₃Br is measured as a function of the magnetic sub level M_J of Rg (³P₂) and the collision energy. For Ar (³P₂), the attenuation process indicates a M_J dependence, in particular, the cross-section of the M_J = 0 state is lower compared with that for other states. On the other hand, Kr (³P₂) shows no M_J dependent attenuation.     

Photolysis of NO2 at multiple wavelengths in the spectral region 200–205 nm

A study of the photodissociation dynamics of NO₂ in the 200–205 nm region using resonance enhanced multiphoton ionization (REMPI) in conjunction with the velocity map imaging technique is presented. We chose this region because it allowed the use of a single laser to photodissociate the NO₂ molecule and probe both the O(¹D₂) fragment using (2+1) REMPI via the 3p'¹P₁ state at 2 ×205.47 nm and the 3p'¹F₃ state at 2 ×203.5 nm, and the O(³P_J) fragments using (2+1) REMPI via the P_J states around 2 ×∼200 nm. Translational energy and angular distributions are extracted from the O(¹D) and O(³P) product images. A growth in the population of highly excited vibrational levels of the NO X(²Π) co-fragment is found as the dissociation wavelength decreases. These are compared with similar trends observed previously for other triatomic O-atom containing molecules. Detailed information on the electronic angular momentum alignment of the ¹D₂ state is obtained from analysis of the polarization sensitivity of the O(¹D) images using the two resonant intermediate states. The angular dependence of the potential energy in the exit channels is examined using long-range quadrupole-dipole and quadrupole-quadrupole interaction terms, from which molecular-frame multipole moments of the total angular momentum of the recoiling O atoms have been calculated. Comparison with the experimentally derived multipole moments is used to help provide insight into the dissociation mechanism.     

Measurements of theg J -factors of12C in the3 P 1 and3 P 2 states

Using the atomic beam magnetic resonance method the Zeeman interactions of¹²C in the³ P ₁ and³ P ₂ states at magnetic fields of about 3.4 kOe have been measured. The measured quantities areg _J (³ P ₁)?g_J(³ P ₂)=15.4(1.0)·10^?6 g _J (³ P ₂)=1.5010616 (50), from which the following value for g_J(³P₁) can be calculated:g _J (³ P ₁)=1.5010770 (50). The experimental results are in moderate agreement with theoretical calculations.     

Theoretical investigations on the Stark-Zeeman effect of the 2p~{}^{\mathsf 2}P3/2-level in 6Li for perpendicularly crossed fields

The splitting behaviour of the P_3/2 hyperfine structure levels is investigated in ⁶Li for homogeneous crossed electric and magnetic fields (Stark-Zeeman effect). This is done by diagonalizing the perturbation matrix comprising the hyperfine interaction, the electronic and nuclear magnetic interaction and the effective electric interaction obtained by transforming the quadratic Stark effect to a first order perturbation interaction. Symmetries are used to find analytic formulae for level shifts and crossing points if only one external field is present. A reflection symmetry unbroken with all three interactions present permits the decomposition of the 12 ×12 matrix into two 6 ×6 submatrices. The structure of energy eigenvalue surfaces epsilon_{F,M F}(B,E) of the two subsystems is found by numeric diagonalization of the perturbation matrix and is displayed in the ranges |B|< 1 mT kV/cm. The total angular momentum F = J + I  (J = 3/2, electronic angular momentum, I = 1, nuclear spin) and the magnetic quantum number M_F provide labels for all surfaces. All crossing points of the energy surfaces have been found. Adiabatic level transfer occurring in atoms traversing a sequence of crossed magnetic and electric fields is explained. Berry phases occur for cycles around some crossing points. Their presence or absence is explained.     

Theoretical study of stereodynamics for the O（3P） ＋ H2 → OH ＋ H reaction

This paper employs the quasi-classical trajectory calculations to study the influence of collision energy on the title reaction on the potential energy surface of the ground ³A' triplet state developed by Rogers et al. (J. Phys. Chem. A 2000 104 2308). It calculates the product angular distribution of P(θ_r), P(φ_r) and P(θ_r, φ_r) which reflects vector correlation. The distribution P(θ_r) shows that product rotational angular momentum vectors j' of the products are strongly aligned along the relative velocity direction k. The distribution of P(φ_r) implies a preference for left-handed product rotation in planes parallel to the scattering plane. Four different polarisation-dependent cross-sections are also presented in the centre-of-mass frame. Results indicate that OH is sensitively affected by collision energies of H₂.     

General multipole expansion of polarization observables in deuteron electrodisintegration

Formal expressions are derived for the multipole expansion of the structure functions of a general polarization observable of exclusive electrodisintegration of the deuteron using a longitudinally polarized beam and/or an oriented target. This allows one to exhibit explicitly the angular dependence of the structure functions by expanding them in terms of the small rotation matrices d ^j _m'm(θ), whose coefficients are given in terms of the electromagnetic multipole matrix elements. Furthermore, explicit expressions for the coefficients of the angular distributions of the differential cross-section including multipoles up to L _max = 3 are listed in tabular form. Received: 19 November 2002 / Accepted: 7 May 2002     

Reactions of excited I*(2P1/2) and unexcited I(2P3/2) iodine atoms in perfluoroalkyl radicals

A method of investigating reactions of excited and unexcited atoms is discussed. It is based on pulsed photolysis of molecules with simultaneous passage of laser radiation through the working medium. The method proposed is used to investigate the reactions that accompany the photolysis of the molecules RI(CF₃I, n-C₃F₇I, i-C₃F₇I). The rate constants of the recombination of iodine atoms into I₂ in the presence of RI molecules are calculated for the atoms I(²P_3/2) and I*(²P_1/2), as are the recombination constants of the radicals R into R₂ and with the atoms I*(²P_1/2) and I(²P_3/2) into the RI molecule. It is shown that the I(²P_3/2) atoms are much more active in the recombination into Ia and RI than the I*(²P_1/2) atoms. The role of the investigated reactions in the kinetics of a photodissociation iodine laser (PDIL) is discussed. The results are compared with the published data.     

Bestimmung derg J-Faktoren in den Zuständen 62 P 3/2 und 82 P 3/2 von133Cs

The hyperfine structures of the 6² P _3/2- and 8² P _3/2-states of¹³³Cs have been investigated by optical double resonance in a strong magnetic field. The Landé-g-factors and the hfs coupling constants were found to be:g _J(6² P _3/2)=1.3340(3)g _J(8² P _3/2)=1.3342(2)a(6² P _3/2)=50.02(25) MHza(8² P _3/2)=7.644(25) MHz. Contrarily to recent measurements, theg _J-factors agree well with the value calculated from the Landé formula.     

Bethe-ansatz solution of a model for a mixed valent impurity with two magnetic configurations: II. Numerical solution of the thermodynamic equations

A mixed valence impurity with two magnetic configurations of total angular momentumJ ₂ andJ ₁=J ₂+1/2, respectively, coupled by conduction electrons with total angular momentum 1/2 via a hybridization matrix element is considered. The thermodynamic Bethe-ansatz equations derived previously are solved numerically for various values ofJ ₂. Thef-level occupation, the entropy, the magnetic susceptibility and the specific heat are obtained as a function of temperature for variousf-level positions. The magnetic field dependence is also discussed in the limit of integer valence (exchange model).Supported by the CONICET, Argentina     

An application of a representation theorem for entropy functionals

The vibrational predissociation of HD₂ ⁺ is modelled in terms of quantum-mechanical tunnelling through a minimal centrifugal barrier at given total angular momentum, J, and with statistical intermode coupling behind the barrier. It is shown that the observed strong preference for the H⁺ + D ₂ predissociation channel (over D⁺ + HD) is consistent with an experimental preference for J values in the range 0 < J < 25, a range which is also shown to be consistent with the observed H₃ ⁺ preferred range of kinetic energy release. A correlation between the total angular momentum and the kinetic energy release is also predicted.     

类铍离子磁四极M2 2s2 1S0—2s2p3P2 (Z=10—103)禁戒跃迁

利用全相对论多组态Dirac-Fock方法系统地计算了高离化类铍离子的磁四极M2 2s²¹S₀—2s2p³P₂ (Z=10—103)自旋禁戒跃迁的能级间隔、跃迁概率和振子强度，计算中考虑了重要核的有限体积效应，Breit修正和QED修正，所得结果和最近的实验数据以及理论值进行了比较，结果表明：高原子序数的高电荷离子(Z≥70)磁四极M2自旋禁戒跃迁几乎可以和中性原子的光学允许跃迁相比拟，不仅在天体等离子体中，在ICF和MCF高温激光等离子体中，磁四极自旋禁戒跃迁和其他自旋禁戒跃迁（磁偶极、电四极）一样不容忽视，在双电子复合、不透明度、自由程等理论计算中应该考虑其影响. 关键词： 磁四极M2 能级间隔 跃迁概率 振子强度     

Energy dependence of nucleon-deuteron elastic scattering observables and its bearing on the3 P J nucleon-nucleon interactions

The energy dependence of neutron-deuteron elastic scattering observables has been calculated from 5 to 45 MeV via rigorous three-nucleon calculations using the Bonn B nucleon-nucleon interaction. The goal of these calculations was to identify energy and angular regions that may be investigated experimentally to study the question of charge-symmetry breaking in the³ P _J nucleon-nucleon forces and/or Coulomb interactions. It was found that the measurement of the neutron-deuteron elastic analyzing power at 16 and 22.7 MeV and its comparison to proton-deuteron data obtained at the same incident energy is the most promising case for studying the issue of charge-symmetry breaking in the³ P _J nucleon-nucleon forces and/or Coulomb interactions.     

Level crossing investigation of the 6p 2 P 3/2 and 7p 2 P 3/2 levels of Cs133, Cs135, and Cs137

The level crossing method has been used for the investigation of the hyperfine structure of the 6p²P_3/2 and 7p²P_3/2 levels of the isotopes Cs¹³³, Cs¹³⁵, and Cs¹³⁷. For the hyperfine coupling constants a and b and for the lifetimes Τ we find: a(6p Cs¹³³)=50.72(3) g_J/?1.345, b(6p Cs¹³³)=?0.38(18) g_J/?1.345 a(7p Cs¹³³)=16.610(6) g_J/?1.3349, b(7p Cs¹³³)=?0.15(3) g_J/?1.3349 a(6p Cs¹³⁵)=53.64(4) g_J/?1.345, b(6p Cs¹³⁵)=7.41(32) g_J/?1.345 a(7p Cs¹³⁵)=17.570(6) g_J/?1.3349, b(7p Cs¹³⁵)=2.35(7) g_J/?1.3349 a(6p Cs¹³⁷)=55.80(4) g_J/?1.345, b(6p Cs¹³⁷)=7.54(20) g_J/?1.345 a(7p Cs¹³⁷)=18.274(6) g_J/?1.3349, b(7p Cs¹³⁷)=2.37(4) g_J/?1.3349 (MHz), Τ(6p²P_3/2)=29.7(2) ?1.345/g_J ns, Τ(7p²P_3/2)=135(1) ?1.3349_Jns. From a comparison with double resonance results the g_J factor of the 7p²P_3/2 level was deduced: g_J(7p²P_3/2=?1.3349(10). Level crossing measurements in the 8p²P_3/2 state of Cs¹³³ give for the g_J factor and the lifetime the following results: g_J(8p²P_3/2)=?1.3353(14), Τ(8p²P_3/2)=310(15) ns. Using recently calculated relativistic correction factors and applying corrections for core polarization and the Sternheimer effect, we obtain for the quadrupole moments: Q(Cs¹³³)=?0.0030 b, Q(Cs¹³⁵)=+0.052 b, Q(Cs¹³⁷)=+0.052 b.     

Rovibronic structure in the electron energy spectrum for associative ionization: Ne(3 P 2), Ar(3 P 2)+H

Associative ionization in thermal energy (300 K) collisions between Ne(2p ⁵ 3s ³P₂), Ar(3p ⁵ 4s ³ P ₂) metastable atoms and hydrogen atomsH(1s ² S _1/2) has been studied by high resolution (20 meV) electron spectrometry. The spectra exhibit structure due to the formation of different vibrational states in the molecular ion and show superimposed rotational structure. Direct information is obtained on the relative population of the rovibronic states and on their energy positions. The well depth of the ionic potential curves has been determined as:D _e (NeH ⁺ X ¹ Σ ⁺)=2.27 (3) eV,D _e (ArH ⁺ X ¹ Σ ⁺)=4.02(3) eV.     

Asymmetric angular dependence of Jc in coated conductors prior to and after fast neutron irradiation

Angular dependent measurements of J_c were performed on a commercial coated conductor (SuperPower) consisting of a 1 μm thick YBCO layer grown on a MgO IBAD buffer layer. An asymmetric behavior of the angular dependence of J_c (J_c(Ф)) was found with a changing distance between the two peaks at different temperatures and applied magnetic fields. One peak always occurs when the field is oriented parallel to the tape surface, the other smaller peak is located in the perpendicular orientation at high fields, but slightly shifted (by up to 10°) at 77 K and low magnetic fields. This peak shift, the overall J_c(Ф) asymmetry and the influence of fast neutron irradiation on J_c(Ф) are discussed. The spherical defects, introduced by collisions of fast neutrons with the lattice atoms, are randomly distributed, add to the as-grown defect structure and change the critical current anisotropy by altering both peaks.     

Relative equilibria of D2H + and H2D+

Relative equilibria of molecules are classical trajectories corresponding to steady rotations about stationary axes during which the shape of the molecule does not change. They can be used to explain and predict features of quantum spectra at high values of the total angular momentum J in much the same way that absolute equilibria are used at low J. This paper gives a classification of the symmetry types of relative equilibria of AB₂ molecules and computes the relative equilibria bifurcation diagrams and normal mode frequencies for D₂H⁺ and H₂D⁺. These are then fed into a harmonic quantization procedure to produce a number of predictions concerning the structures of energy level clusters and their rearrangements as J increases. In particular the formation of doublet pairs is predicted for H₂D⁺ from J ≈ 26.     

Polarized fluorescence of jet-cooled molecular iodine

The degree of polarized fluorescence of molecular iodine ¹²⁷I₂ cooled in a supersonic jet under rotationally selective excitation in the electronic transition B ³Π_0u ⁺-X ¹Σ _g ⁺ has been measured and calculated. It was found that the interaction of the angular momentum of the molecule with the nuclear spins of iodine atoms leads to a considerable depolarizing effect. This effect is most pronounced for small rotational quantum numbers of the angular momentum that are comparable with the total nuclear spin of the iodine molecule, which is equal to 5.     

强磁场下He2++H(1s)的碰撞激发过程的态选择截面研究

强磁场下的重粒子碰撞激发过程是重要的非弹性碰撞过程, 但相关研究还几乎是空白. 应用经典蒙特卡洛的方法在得到无磁场下He²⁺+H(1s)的碰撞激发截面的基础上, 详细研究了不同强度的纵向和横向强磁场环境下到不同主量子数n和磁量子数m的碰撞激发过程的态选择截面. 同时用非微扰量子方法, 得到了强磁场下靶原子的能级, 并分析了其随磁场强度变化的原因. 对碰撞过程发现由于磁场的引入导致到不同m态的激发截面有较大的分离, 同时在较低入射能区的态选择截面变化行为与磁场方向有很大关系, 这与能级变化及横向强磁场所特有的抗磁项的相互竞争有密切联系. 通过对有关事例、径迹的分析, 解释了这些变化形成的原因. 也发现由于核的运动, 沿磁场方向的轨道角动量并非绝对守恒, 而有微小的变化. 关键词： 重粒子碰撞激发 经典蒙特卡洛模拟 强磁场 态选择截面     

Transition magnetic moments of J~P=3/2~+ decuplet to J~P=1/2~+ octet baryons in the chiral constituent quark model

In light of the developments of the chiral constituent quark model(χ~(CQM)) in studying low energy hadronic matrix elements of the ground-state baryons, we extend this model to investigate their transition properties.The magnetic moments of transitions from the J~P=3/2~+ decuplet to J~P=1/2~+ octet baryons are calculated with explicit valence quark spin, sea quark spin and sea quark orbital angular momentum contributions. Since the experimental data is available for only a few transitions, we compare our results with the results of other available models. The implications of other complicated effects such as chiral symmetry breaking and SU(3) symmetry breaking arising due to confinement of quarks are also discussed.