S3分子的几何结构: 分子轨道从头算和Franck-Condon分析

在考虑Dusehinsky效应情况下,给出了多维Franck-Condon因子的理论计算公式;利用分子轨道从头算,完成了S3分子的(～X)1A1态和S-3分子的(～X)2B1态的几何结构优化和谐振频率分析,模拟了S-3的光电子能谱.在光谱模拟中,利用迭代Franck-Condon分析,得到了S3分子的(～X)1A1态的几何构型参数:r(SS)=1.94±0.02 (°A)和∠((S-S-S)=117.35±0.05°.由所得的S3分子的键角对Nimols等人得的结果[J.Phys.Chem.1986.90:2574]给出一个新的解释.     

S2O‾自由基光电子能谱的Franck-Condon分析

本文考虑多振动模混合和热带效应,凭借谐振子模型,推得计算两维-四振动模Franck-Condon重叠积分的解析表示,且应用于S2O‾ 自由基光电子能谱的理论研究。对于S2O( 1A′) – S2O‾( 2A″) 光脱附过程,结合分子轨道从头算和密度泛函理论,计算Franck-Condon因子,从而得到电子跃迁振动谱线的相对强度,理论上得到的光电子能谱与实验上观测到的能谱达到较好的一致;进一步在光谱模拟过程中,拟合实验能谱得到可靠的负离子自由基S2O‾电子态（ 2A″）的几何结构参数：键长R(SS) = 2.008 +/-0.005Å 和 R(SO) = 1.519+/-0.005Å.     

CF-2光电子能谱的Franck-Condon分析

在Born-Oppenheimer近似下,结合分子轨道从头算,采用谐振子模型和产生函数方法计算了CF2(X1A1)←CF-2(X2B1)跃迁的Franck-Condon因子.用迭代Franck-Condon分析(IFCA)方法对CF-2的光电子能谱进行了拟合,得到了基态CF-2的几何构型:r CF=0.142 9±0.000 1 nm,θFCF=101.10±0.01度.     

磷基的几何结构与光电子能谱

基于ab initio/DFT理论,对磷基分子以其阴离子态进行了几何结构优化和谐振频率计算。在B3LYP/6-311+G(2d,p)理论水平下,通过Franck-Condon因子计算模拟了磷基的光电子能谱[K. M. Ervin and W. C. Lineberger, J. Chem. Phys. 122 (2005) 194303],计算得到的理论谱与实验谱完全一致。另外,通过迭代Franck-Condon分析,得到优于ab initio/DFT理论计算的离子的几何结构参数。     

磷基的几何结构与光电子能谱

基于ab initio/DFT理论,对磷基PH2分子X~2B1态和PH-2阴离子X~1A1态进行了几何结构优化和谐振频率计算.在B3LYP/6-311+G(2d,p)理论水平下,通过Franck-Condon因子计算模拟了PH-2实验的光电子能谱,计算得到的理论谱与实验谱完全一致,确认属于PH2(X~2B1)-PH-2(X~1A1)光脱附过程.另外,通过迭代Franck-Condon分析,得到优于ab initio/DFT理论计算的PH-2离子的几何结构参数R(PH)=0.1438±0.0002 nm和∠(HPH)=92.2±0.2°.     

NO通过C~2Π←X~2Π跃迁的共振多光子离化谱

以皮秒Nd∶YAG激光器抽运光学参变发生 /放大器做激发源 ,得到了NO分子在 4 90～ 5 80nm波长范围内通过C2 Π态共振增强的多光子离化谱 ,离化谱由有规则的谱线序列组成。将理论计算的峰值位置与实验结果进行比较 ,确定了离化通道为 :NO(X2 Π) 3hνNO(C2 Π) 2hν(orhν) NO+ +e ,离化信号强度随激光强度的近五次方变化关系进一步验证了此结论。分析讨论了谱线强度的分布不符合夫兰克康登原理的可能原因。根据谱线峰值位置 ,利用最小二乘法拟合获得NO分子C2 Π态振动常数′ωe=(2 35 4 .9± 6 .4 )cm-1,′ωe ′χe=(14 .7± 2 .5 )cm-1及平衡位置的力常数k=(2 .4 4± 0 .0 8)× 10 3 N·m-1。结果可为用激光离化光谱技术探测大气污染物NO分子提供参考。     

Analysis of the Photoelectron Spectra of Selenium Difluoride and Selenium Dichloride Based on Franck-Condon Factors

The vibrational structure of the photoelectron spectra of selenium difluoride and selenium dichloride have been simulated using the computed Franck-Condon factors in the harmonic oscillator approximation. Spectral simulations have been carried out employing the coupled-cluster singles, doubles, and triples (CCSD(T)) and the Becke three-parameter Lee, Yang, and Parr (B3LYP) values for the ground electronic states of the neutral molecules and the cations selenium difluoride and selenium dichloride, respectively. The Duschinsky rotations among the normal modes of two ground electronic states of species involved in the transition are fully taken into account. The ionization energies obtained for selenium difluoride and selenium dichloride are in reasonable agreement with the experimentally determined values. The spectral simulations of vibrational structures including frequency changes and Duschinsky rotation upon the electronic excitation are in agreement with the experimental results.     

CN~+离子电子结构和跃迁性质的理论研究

采用多组态参考相互作用方法和AV5Z-DK基组对CN~+离子的两个解离极限C~+(~2P_u)+N(~2D_u)和C~+(~2P_u)+N(~4S_u)下的X~1Σ~+、a~3Π、~1Δ和A~1四个电子态的势能曲线、永久偶极矩和振动能级进行了计算.为保证计算结果的精确性,在计算中考虑了Davidson修正.基于求得的势能曲线,数值求解一维径向薛定谔方程得到了各个电子态的光谱数据,并与实验值和已有的理论值吻合较好.除此之外,对A~1Π→X~1Σ~+和1~1Δ?A1~Π的跃迁性质进行了研究,同时通过跃迁的弗兰克-康登因子及辐射寿命,对CN~+离子激光冷却的可行性进行了分析.     

Cs_2(B~1Π_u)态与基态Cs原子间的碰撞激发转移

在Cs2密度约为2×1013 cm-3的纯Cs样品池中,脉冲激光激发Cs2(X1 Σg+)至B 1Πu态,利用原子和分子荧光光谱方法研究了Cs2(B 1Πu)+Cs(6S)的碰撞激发转移过程.用736 nm激发Cs2到B 1Πu(v＜10),这时预解离不发生.由B 1Πu→X1 Σg+时间分辨跃迁信号得到B 1Πu态的辐射寿命为(35±7)ns,B1Πu态与Cs原子碰撞转移总截面为(4.0±0.5)×10-14 cm2.用705 nm激发至B 1Πu(v＞30)态,这时发生预解离,在不同的Cs密度下,测量了I(D1),I(D2)和分子带的时间积分荧光的相对强度,得到了预解离率为(4.3±1.7)×105 s-1(对预解离到6P3/2)和(4.7±1.9)×106 s-1(对预解离至6P1/2);碰撞转移截面为(0.45±0.18)×10-14 cm2(对转移到6 P1/2)和(4.3±1.7)×10-14 cm2(对转移到6P3/2).结果表明,如果B 1Πu(v)是束缚的,6P原子由碰撞转移产生;如果B 1Πu(v)是预解离的,则6P原子由预解离和碰撞转移产生.     

The X2 Pi and A2 sigma states of FCN+ and ClCN+ : ab initio calculations and simulation of the HeI photoelectron spectra of FCN and ClCN

Geometry optimization and harmonic vibrational frequency calculations at the CASSCF, MP2 and CCSD(T) levels with basis sets up to 6-311G(2df) quality were carried out on the X¹Σ⁺states of FCN and ClCN and the X²Π and A²Σ⁺ states of their cations. Adiabatic ionization energies were calculated up to the CCSD(T)/6-311G(3df)//CCSD(T)/6-311G(2d) level. Some B3LYP calculations were performed also for the ground states of the neutral molecules and the cations. Franck-Condon simulations were performed for the first two bands in the He I photoelectron spectra of FCN and ClCN by employing the ab initio computed geometries and frequencies. By comparing the observed and the simulated spectra obtained from different CN and CX (X = F or Cl) ionic bond lengths chosen on the basis of the ab initio computed values, the following structural parameters are obtained for the two lowest-lying states of FCN⁺ and ClCN⁺ (the method of deriving the uncertainties is described):     

MgF2：V^2＋晶体能级和振动结构的DV—Xa研究

首次用DV-X_a方法计算了终端声子激光晶体MgF_2:V~(2+)的电子能级和振动结构,给出的晶场能级与实验值相当接近.使用晶格振动的“呼吸”模型,得到了基态~4B_(1g)和第一激发态~4B_(2g)的振动势能曲线.在简谐振动近似下,它们分别具有454cm~(-1)和460cm~(-1)的声子能量,与实验值399cm~(-1)符合很好.另外,还获得晶体振动的黄昆参数,激活能,和Franck—Condon交距等参数.计算了四种温度(0K,2K,77K和300K)下的振动线形,并与2K的实验吸收谱作了比较.     

计算机模拟技术在研究传能反应产物振动布居中的应用

本文讨论了利用计算机模拟技术研究传能产物振动布层的理论和方法。以Ａｒ（＾３Ｐ０．２）＋ＰＣｌ３反应生成ＰＣｌ（Ａ＾３П）为例，对模拟的过程和其中应注意的问题进行了分析。文中首次报道了ＰＣｌ（Ａ＾３П→Ｘ＾３Σ＾－１）跃迁的Ｆｒａｎｃｋ－Ｃｏｎｄｏｎ因子。     

The Comet-Tail (A(2)Pi(i)-X(2)Sigma(+)) System of (12)C(16)O(+): A Reinvestigation

The emission spectrum of the comet-tail (A(2)Pi(i)-X(2)Sigma(+)) system of (12)C(16)O(+) produced in the cathode glow of a hollow-cathode discharge tube and photographed in the spectral region 3345-8500 ? at high resolution was reinvestigated. Detailed rotational analysis of 10 bands involving 5 vibrational levels v = 0 to 4 of each of the A and X states was carried out. Spin-splitting of the rotational levels was observed for the analyzed bands. The observed intensity distribution of the branches is found to be in good agreement with theoretical calculations. Molecular constants for both the A and X states were obtained from a global fit of the present data of the A-X system and the infrared and microwave data available from the literature for v = 0, 1, 2, 3, and 4 of state X, using effective Hamiltonian for the A(2)Pi state and matrix elements for both A and X states. The present work suggests that the A(2)Pi(i) state changes from Hund's case (a) at low J values to Hund's case (b) at high J values. Copyright 2000 Academic Press.     

Experimental and Theoretical Study of the Electronic States and Spectra of TeH and TeLi

Gas-phase emission spectra of the hitherto unknown free radical TeLi have been measured in the NIR range with a Fourier-transform spectrometer. The emissions were observed from a fast flow system in which tellurium vapor in argon carrier gas was passed through a microwave discharge and mixed with lithium vapor in an observation tube. Two systems of blue-degraded bands were measured at high spectral resolution in the ranges 8000-9000 and 5700-6700 cm(-1) and vibrational and rotational analyses were performed. In order to aid in the analysis of the experimental data, a series of relativistic configuration interaction calculations has been carried out to obtain potential curves for the low-lying states of TeLi and the isovalent TeH and also electric dipole transition moments connecting them. As in the TeH system, the ground state of TeLi is found to be X(2)Pi(i), but with a remarkably smaller spin-orbit splitting. The TeLi calculations indicate a strongly bound A(2)Sigma(+) state, while in TeH the analogous state is computed to lie significantly higher at approximately 32 000 cm(-1), and it is strongly predissociated. Based on the theoretical analysis, the observed TeLi band systems are assigned to the transitions A(2)Sigma(+)(A1/2)-->X(1)(2)Pi(3/2)(X(1)3/2) and A(2)Sigma(+)(A1/2)-->X(2)(2)Pi(1/2)(X(2)1/2). Analysis of the spectra has yielded the molecular constants (in cm(-1)) X(1)(2)Pi(3/2):omega(e)=457.49(3), omega(e)x(e)=2.482(9), B(0)=0.408908(8); X(2)(2)Pi(1/2): T(e)=2353.44(3), omega(e)=456.28(4), omega(e)x(e)=2.635(8), B(0)=0.414954(8), p(0)=1.00637(4); A(2)Sigma(+): T(e)=8574.64(2), omega(e)=437.81(3), omega(e)x(e)=2.581(8), B(0)=0.423903(8), p(0)=-0.19915(2), where the numbers in parentheses are the standard deviations of the parameters. Comparison of the isovalent TeLi and TeH systems emphasizes that the difference in bonding character (ionic in TeLi vs covalent in TeH) is responsible for qualitative differences in the electronic spectra of these two molecules. Copyright 2001 Academic Press.     

锂分子3^1Ⅱg里德堡态的光谱研究

我们用脉冲光学-光学双共振荧光激发谱（OODR），测量了在35500-38000cm^-1能量范围内的里德堡态，观察到^7Li23^1Ⅱg态的10个振动能，本文观测的3^1Ⅱg态的146条激发谱线进行了归属，得到了新的Dunhm常数，RKR势能曲线以及A^1∑u^ 到3^1Ⅱg态跃迁的夫兰克-康登因子，并且讨论了3^1Ⅱg态的双重分裂以及与附近里德堡态F（4）^1∑g^ ,5^1∑g^ ,6^1∑g^ 和G（2）^1Ⅱg的微扰，发现在我们的实验精度下（0.2cm^-1)3^1Ⅱg态掇重分裂可以忽略。     

Study on the Baryon State X Produced in the Process J/ψ→p+X,X→Δ+π

The existence of the new class of hadronic states, glueball, hybrid mesons and hybrid baryons, is one of the important prediction of the QCD. It is an excited and attractive research preject to search for and identify these non-qq meson and non-qqq baryon states. The theoretical expectations on the mass spectrum of hybrid baryons have been carried out in the bag model, QCD sum rules and flux tube model. We might expect that J/ψ hadronic decay processes are the good place to study hybrid baryons. The J/ψ decay process J/ψ→p+X,X→Δ+π, where p and Δ are the antiproton and Δ baryon with spin parity (3/2)⁺, respectively, are studied in terms of the angular distribution and the generalized moment analysis methods. Precise angular distribution and moment representation of baryon resonance (including the hybrid baryon) X with spin parity (1/2)^±,(3/2)^±,and (5/2)^± are obtained. They can be used to identify the spin of the baryon resonance state X.     

Spectroscopic characterization and potential energy functions of the six low-lying electronic states of ArKr+

Pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectra of ArKr have been recorded in the wavenumber range 108,000–118,000 cm^?1 using a 1 + 1′ two-photon resonant excitation scheme from the ground X 0⁺ state of ArKr via selected intermediate states located just below the Ar(¹S₀) + Kr([5p[1/2]₀) dissociation limit. The positions of ionic vibrational levels with quantum numbers from 1 to 30, from 0 to 8 and from 0 to 6 were determined for the X(1/2), A₁(3/2) and A₂(1/2) states, respectively. The assignment of absolute vibrational quantum numbers of the ionic states was derived from the isotopic shifts of the spectral lines. Combining these data with literature data on the B(1/2) → X(1/2), C₁(3/2) → A₁(3/2) and C₂(1/2) → A₂(1/2) band systems of ArKr⁺ enabled the derivation of potential energy functions for the lowest six electronic states of ArKr⁺ using a global potential model that includes the effects of the spin-orbit, charge-exchange and long-range interactions.     

含Ho~(3+)的GeO_2-B_2O_3-BaO-Na_2O-Al_2O_3锗酸盐玻璃的光谱与增益特性

用高温熔融法制备了不同Ho3+离子掺杂浓度65GeO2-12B2O-10BaO-10Na2O-3Al2O3-χHo2O3(χ=0.25,0.75,1.25mol%)锗酸盐玻璃。从吸收特性出发,应用McCumber理论计算了Ho3+离子能级5I8→5I7(~2.0μm)跃迁的吸收截面和5I7→5I8的受激发射截面。根据掺杂离子的浓度以及获得的吸收截面和受激发射截面得到Ho3+离子在此玻璃中的增益截面函数,从该函数可反映出材料的粒子数反转特性。获得的基本光学参数与其它掺杂的玻璃进行了比较,其吸收截面、发射截面和增益截面的最大值具有一定的优势。认为该玻璃在~2.0μm波段的中红外激光器中将有潜在的较大应用前景。     

NaK(61Σ+)与H2碰撞传能中的H2的振转态分布

光学-光学双共振激发NaK至61Σ+高位电子态,研究了NaK(61Σ+)与H₂的电子-振转能量转移。利用相干反斯托克斯拉曼散射(CARS)光谱技术检测H₂的振转态分布。扫描CARS谱表明H₂在(1,1),(2,1),(2,2),(2,3),(3,1),(3,2),(3,3)和(3,5)振转能级上有布居。对于(3,1), (3,2), (3,3)和(3,5)能级,扫描CARS谱峰值直接给出布居数之比。对于(1,1), (2,1), (2,2)和(2,3)能级,扫描CARS谱峰值给出二个可能的布居数之比,利用一个速率方程组,由时间分辨CARS轮廓可以得到真实的比值。用n₁～n₈分别表示H₂的(3,1), (2,1), (1,1), (3,3), (2,3), (2,2), (3,2)和(3,5)能级上布居密度,得到n₂/n₁～n₈/n₁分别为0.51,0.97,0.45,0.18,0.10,0.26和0.31。利用Stern-Volmer公式,得到61Σ+态的总退布速率系数为(2.1±0.4)×10-10 cm3s-1, 由H₂各振转能级布居数之比,得到61Σ+-(1,1), (2,1), (2,2), (2,3), (3,1), (3,2), (3,3)和(3,5)转移速率系数(10-11 cm3·s-1单位)分别为5.4±1.6,2.8±0.8,0.6±0.2,1.0±0.3,5.6±1.7,1.4±0.4,2.5±0.8和1.7±0.5。     

Dynamics mechanism of optical-optical double-resonant multiphoton ionization of nitrogen dioxide

The optical-optical double-resonant multiphoton ionization (OODR-MPI) spectrum of NO2 molecule in the 460-605-nm wavelength region of the probe photon is presented. The mechanism of the OODR-MPI of NO2 molecule is analyzed. The results show that the resonant features can be assigned to the transitions from the first 3sσg Rydberg intermediate resonant state to the final npσu Rydberg series. The ionization pathway is NO2 (X2A1) 3hv1→ 3sσghv2→npσu hv2 or autoionization→NO2+ + e. It is found that the converging potential of the npσu Rydberg series and the quantum defect of np orbit about NO2 are (78803 ± 14) cm-1 and 0.652 ± 0.014, respectively. The bending vibration frequency of 5pσu state is determined also.