Ba原子6pnd(J=1,3)自电离光谱的实验研究

采用三台可调渚激光实施孤立实激发,分三步将处于基态的Ba原子激发到6P1/2nd(J=1,3)和6p3/2nd(J=1,3)自电离态上,获得了分别从6snd1D2(n=7-15)和6sad3D2(n=7-12)激发而得到的6p1/2nd(J=1,3)和6p3/2nd(J=1,3)自电离光谱,重点对主量子数n较低的自电离态进行了实验研究.通过光谱的线形拟合得到了上述能级的位置和宽度等数据,进而获得了量子弓损和约化宽度等信息.通过对不同系列的自电离光谱的分析和比较,详细讨论了这些自电离态的光谱特征及其复杂光谱结构的成因.     

Coriolis interaction in the local mode (n100;F2) combination states of GeH4

Coriolis interactions in local mode (n100) combination states of GeH₄ are studied. Three widely used local mode models, the normal mode model with Darling–Dennison resonance included (NMDD) model and the anharmonically coupled anharmonic oscillator (ACAO) model with two different kinds of bond stretching variable, were used to calculate the values of the interaction parameters. As a test of these three models, the Coriolis interaction parameters of the local mode (3100) combination bands of the ⁷⁴GeH₄,⁷²GeH₄ and ⁷⁰GeH⁴ species, recorded at a resolution of 0.015cm^-1 on a Bruker IFS120HR Fourier transform spectrometer, are compared with the calculated results. There is good agreement.     

钙原子4p_(1/2,3/2)ng(J=3)自电离Rydberg光谱的研究

利用Monte Carlo(MC)方法模拟研究了薄膜生长的初始阶段岛的形貌和岛的尺寸与基底温度和入射粒子剩余能量之间的关系.模型中考虑了粒子的沉积、吸附粒子的扩散和蒸发等过程.结果表明当基底温度从200K变化到260K时,岛的形貌经历了一个从分散生长逐渐过渡到分形生长的过程,并且在较低温度(200K)下,随入射粒子剩余能量的增加,岛的形貌也经历了同样的变化过程.进一步研究证明,随着基底温度的升高或入射粒子剩余能量的增加,沉积粒子的扩散能力显著增强,从而使岛的形貌发生了改变.     

Su(4) approach to fourfold degenerate electronic states of some hexafluoride molecules

We show that two appropriate realizations of the su(4) algebra allow the construction of all electronic operators needed for the study of vibronic and rovibronic interactions in a G^′ electronic state. In each case a full bosonic realization is made and all matrix elements are calculated. Illustrations of our formalism and comparisons with previous approaches are made in the case of ν₅(F_2g) and ν₃(F_1u) modes.     

Properties of doubly excited states of H- and He associated with the manifolds from N = 6 up to N = 25

This paper discusses theory and results on ¹P⁰ doubly excited states (DES) in He and in H^- of very high excitation, up to the N = 25 manifold. Our calculations employed full configuration interaction (CI) with large hydrogenic basis sets and produced correlated wavefunctions for the four lowest roots at each hydrogenic manifold by excluding open channels and the small contribution of series belonging to lower thresholds. The suitability of the hydrogenic basis sets for such calculations is justified, apart from their practicality, by the fact that, by computing from them natural orbitals, the results were shown to be the same with those of earlier multiconfigurational Hartree-Fock (MCHF) calculations on low-lying DES. In total, 160 states were computed, most of them for the first time. Their energy spectrum should be of use to possible future photoabsorption experiments. For certain low-lying DES up to N = 13, for which previous reliable results are available, comparison of the calculated energies shows good agreement. The correlated wavefunctions contain systematically chosen single and double excitations from each hydrogenic manifold of interest. From their analysis, we determined the “goodness" of different quantum numbers and the geometry (average angles and radii) as a function of excitation. For the Sinano lu-Herrick ( K , T ) classification scheme, whose basis is a restricted CI with hydrogenic functions and which has thus far been tested only on low-lying DES, we established that, whereas T remains a good index as energy increases, K does not. Consequently, a more flexible than K quantum number is needed in order to account for most of the additional correlation. This number, represented by F = N - K - 1, where N and K are not good numbers anymore, produces consistently a much higher degree of purity than the ( K , T ) scheme does, especially as N increases and as the relative significance of various virtual excitations due to electron correlation increases. Among the four states of each manifold, in all cases in H^- and in most cases in He, the three are of the intrashell type and one is of the intershell type with ( F , T ) = (0, 0). The lowest intrashell states and the lowest intershell states exhibit a wide angle geometry tending to 180 ^° as N ↦∞. Received 10 September 2001 and Received in final form 12 November 2001     

Diagonal and Off-Diagonal Recursion Relation for the General Potential V(r) = Arp

A recursion relation is derived for the potential V(r) = Ar ^p. Generally, this connects off-diagonal matrix elements of r ^k–2, r ^k+p, r ^k, and r ^k+2. The diagonal case is obtained by setting m = n in this relation. The relation is derived by elementary methods and without recourse to specific properties of the eigenstates. Finally, this relation is studied for the familiar potentials p = –1, 1, 2.     

Channel interaction of Ba 6pns （J=1） autoionizing series

The channel interactions between the Ba 6pnl (J=1) autoionizing series with different l and n have been observed by means of unsaturation and saturation excitation methods.The observed interactions were interpreted with the spectral density calculated from the multichannel quantum defect theory,the results of which are quite satisfactory.     

Surface resonant states and the adsorption of 4d atoms on Mo (110) and (100)

The adsorptive properties of Mo (110) and Mo (100) relative to 4d transition adatoms are investigated and compared using a tight-binding model. The surface resonant states existing on the (100) free surface are shown to have a drastic influence. On Mo (110) a Mo adatom retains a strong atomic character while on Mo (100) one approaches a surface molecule limit which is due to a strong interaction between the adsorbate atomic state and the free surface resonance. Consequently a large anisotropy of binding energy is found. The case of different 4d adatoms is also discussed.     

The vapor-phase Raman spectra,Raman band contour analyses,Coriolis constants,and force constants of spherical-top molecules MX4 (M = Group IV element, X = F,Cl, Br,or I)

The Raman spectra of 21 tetrahalides of Group IV have been recorded in the vapor phase at temperatures between 20 and 420° C. The Raman shifts of the Q branches of each fundamental are reported. In agreement with the selection rules, the ν₁(a₁) fundamental of each molecule has no rotational structure. With two exceptions, the separation between the OP and RS branches of the ν₂(e) fundamental of each molecule has been measured and found to be in close agreement with that calculated from an extended form of the Placzek-Teller theory. Due to first-order Coriolis coupling, the OP, RS branch separations of the ν₃(t₂) and ν₄(t₂) fundamentals of each molecule are different from each other and from those of the ν₂(e) fundamental. It has been possible to determine Coriolis constants for most of the tetrahalides from these branch separations, using both a previously published procedure and also a new procedure in which analytical expressions for each subbranch are derived. There is close agreement between the zeta values so determined and the corresponding values determined from infrared band contour analyses in those cases where the latter are available. Force constants based on the fundamental frequencies and the zeta values are reported.     

High-Lying Rotational Levels of Water: Comparison of Calculated and Experimental Energy Levels for (000) and (010) up to J = 25 and 21

Emission spectra of methane-oxygen low-pressure flames have been recorded at a resolution of 0.02 cm-1 with an infrared Fourier transform spectrometer in the spectral ranges 780-1370 and 1800-5000 cm-1. The flame temperature was about 1850 K and a large number of transitions involving J values as high as 34 for an extended set of vibrational states could be assigned. Combined with already published data sets on H2O, our line position analysis yielded rotational energy levels for many of these states, but only the results relevant to the ground and the (010) states are presented here. The experimental energies for these two states have been fitted with the help of the bending-rotation Hamiltonian approach [L. H. Coudert, J. Mol. Spectrosc. 181, 246-273 (1997)], and for each rotational level, the calculated energy along with its uncertainty is reported and compared with the observed value. Comparisons with other available energy level data sets for the ground and (010) states are also presented. Copyright 1999 Academic Press.     

g-Factor for the K=6, Jπ=6+ isomer in178Hf

Hyperfine Interactions -     

SiX2(X=H,F)分子的结构与势能函数

应用QCISD/6-311++G(3df,3pd)和B3P86/6-311++G(3d2f)对SiH2,SiF2的结构进行了优化,优化出SiH2分子的稳定构型为C2v,电子态为1A1,其平衡核间距Re=0.15149 nm、键角∠HSiH=92.5025°,离解能为3.7098 eV.SiF2分子的稳定构型为C2v,电子态为1A1,其平衡核间距Re=0.16014 nm、键角∠FSiF=100.7079°、离解能为14.1391eV.并对它们的力常数及谐振频率进行了进一步的计算.在推断出SiX2(X=H,F)的离解极限的基础上,应用多体展式理论方法,导出了基态SiX:(X=H,F)分子的解析势能函数,该势能表面准确地再现了SiX:(X=H,F)分子的结构特征和能量变化.分析讨论势能面的静态特征时得到SiH+H-SiH2反应中存在鞍点,活化能为192.971 kJ/mol,为有阈能的反应.而SiF+F→SiF2反应中没有鞍点,是无阈能的反应.     

YnO(n=16,17,18)分子基态的结构与分析势能函数

应用密度泛函理论的B3LYP方法,在Y的有效原子实势近似下,O原子选用6-311+G(3df)和AUG-cc-PVTZ基组,优化计算了Y nO(n=16)分子基态的能量,平衡结构,和谐振频率。根据原子分子反应静力学原理,导出了Y nO(n=16,17,18)分子基态的合理离解极限。通过优化计算结果和已有的实验数据对比,得出CRENBL ECP/AUG-cc-PVTZ混合基组为对体系进行计算的最优基组。基于此,在B3LYP/ CRENBL ECP/AUG-cc-PVTZ水平也对Y nO(17,18)进行了结构优化和频率计算,同时对YO分子基态的势能面进行了单点能扫描。并采用最小二乘法拟合得到了相应的Murrell-Sorbie势能函数。计算出了相应的力常数（f2,f3,f4）和光谱常数（Be, αe, ωe, ωeχe,De）。结果与已有的实验数据吻合的很好。     

YnO(n=16,17,18)分子基态的结构与分析势能函数

应用密度泛函理论的B3LYP方法,在Y的有效原子实势近似下,O原子选用6-311+G(3df)和AUG-cc-PVTZ基组,优化计算了Y nO(n=16)分子基态的能量,平衡结构,和谐振频率。根据原子分子反应静力学原理,导出了Y nO(n=16,17,18)分子基态的合理离解极限。通过优化计算结果和已有的实验数据对比,得出CRENBL ECP/AUG-cc-PVTZ混合基组为对体系进行计算的最优基组。基于此,在B3LYP/ CRENBL ECP/AUG-cc-PVTZ水平也对Y nO(17,18)进行了结构优化和频率计算,同时对YO分子基态的势能面进行了单点能扫描。并采用最小二乘法拟合得到了相应的Murrell-Sorbie势能函数。计算出了相应的力常数（f2,f3,f4）和光谱常数（Be, αe, ωe, ωeχe,De）。结果与已有的实验数据吻合的很好。     

Translational heating of D(2) molecules thermally desorbed from Si(100) and Ge(100) surfaces

The translational energies of D(2) molecules thermally desorbed from the Si(100) and Ge(100) surfaces under a heating rate of 6 K/s have been measured. In contrast to the previous laser desorption study, results show a considerable translational heating; the observed translational temperature is about 3 times higher than the desorption temperature for both surfaces. This fact indicates that energy barriers for adsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption and desorption dynamics of hydrogen on the Si(100) surface.     

Branching ratios of successive emission (up to three) of C2n + (n = 1–5) fragments in asymmetrical fission processes of C60 r+ ions (r = 4–6)

Highly charged C₆₀ molecules are produced in collisions between neutral C₆₀ and multiply charged ions within a large range of temperatures. Successive emission of one, two or three light monocharged fragments referred as one-, two- and three-step processes have been observed. The experimental mass branching ratios for the emission of one C_2n⁺ fragment from C₆₀⁶⁺, C₆₀⁵⁺ and C₆₀⁴⁺ ions are compared with the theoretical values using a statistical model. From hotter C₆₀⁶⁺ ions, branching ratios for three-step processes have been measured and the data are in good agreement with an estimation using the branching ratios in one-step process.