共查询到18条相似文献,搜索用时 312 毫秒
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报道了Na2+离子的三个低激发态1Σu、2Σg、2Σu在二个光脉冲作用下的解离动量谱,激光波长为680nm,各脉冲功率为1×1012W/cm2,脉宽50fs,从研究结果可见,其单光子、双光子、三光子激发的对应的解离峰及峰值随相对相位而变,并且这种影响随延时增大而减小. 相似文献
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HD+离子在两个超短脉冲激光场作用下的解离几率分布 总被引:2,自引:2,他引:0
本文报告HD+离子在波长λ=306.7nm的三倍频超短脉冲弱光场E3和不同延时的二倍频超短脉冲强光场E2作用下解离几率分布的定量计算结果。E3和E2的脉冲宽度均为10fs.E3先行,E2延时取0、4、8、12、16、20、24、28fs.计算结果用三维图表出。图中看到,沿相对动量坐标有三个峰,分别位于动量2.1×10-18、4.4×10-18、5.8×10-18g·cm/s处,依次称为1号峰、2号峰、3号峰,位置各是λ=306.7nm的单光子能量、双光子能量、三光子能量消耗于解离能之后离子碎片具有相对动量。据分析,1号峰来源于E2场引起的受激发射作用。 相似文献
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OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1Πg, (7d)1Πg HIGH-LYING RYDBERG STATES IN Na2 下载免费PDF全文
Two 1Πg states of Na2 for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B1Πu state are identified by the numerical calculations with the molec-ular constants for B1Πu←X1Σg+ transitions and confirmed by the complemen-tary A1Σg+←X1Σg+ polarization spectra. Absolute vibrational numberings of the (6d)1Πg and (7d)1Πg states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)1Πg, (7d)1Πg states are reported. 相似文献
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在193 nm的单色激光实验中,本文利用时间切片离子速度成像技术,研究了经193 nm双光子电离得到的Si2+的解离反应动力学过程. 根据实验得到的Si+离子的速度成像,观测到了两种离子直接解离通道:Si(3Pg)+Si+(2Pu)和Si(1D2)+Si+(2Pu). 电子基态的Si2分子处于v=0∽5的振动态上,其经过双光子电离后激发到Si2+离子的多个电子激发态势能面,生成主要通道Si(3Pg)+Si+(2Pu),其中v=1的解离信号最强. 此外,由于势能曲线22Πg与32Πg相同对称性引起的避免性势能面交叉,生成次要反应通道Si(1D2)+Si+(2Pu). 通道Si(1D2)+Si+(2Pu)的产物亦可以由生成的基态Si2+(X4Σg-)吸收一个193 nm光子后解离得到,其对应产物则具有更大的动能. 相似文献
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使用对称性匹配簇-组态相互作用方法首次计算了Li2分子自旋一致激发态a3Σ+u和b3Πu的离解能、平衡几何及其谐振频率。使用最小二乘法、利用Murrell-Sorbie函数形式拟合出了Li2分子三重态的第一激发态a3Σ+u 和第二激发态b3Πu的完整势能函数,并计算了这两个态的光谱常数 (Be, αe, ωe 和 ωeχe) 和力常数 (f2, f3和f4)。得到了Murrell-Sorbie函数形式既适用于基态、又适用于激发态的结论。将计算得到的激发态(a3Σ+u和b3Πu)的离解能、平衡几何及其谐振频率与实验结果及其它理论计算结果进行了比较。从比较的结果中可以清楚地看出,本文的计算结果在计算精度方面有很大的改进。 相似文献
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根据最新的Cs2分子中间态A1∑+u -b3Πu全局解微扰获得的能级数据, 归属了通过微扰增强红外-红外光学双共振中间态A1∑+u 到上态23△1g的140条碰撞线, 包含之前实验观测到的221条23△1g←A1∑+u← X1∑+g 双共振跃迁[J. Chem. Phys. 128, 204313 (2008)], 重新计算了23△1g态的分子常数和势能曲线(排除54个微扰能级). 本次拟合得到的离心畸变常数和从经验公式计算得到的值相符合. 在亚多普勒激发光谱中,没有分辨出23△1g态的超精细结构. 对23△1g态的超精细结构进行初步计算,比较实验结果给出解释和说明. 相似文献
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本文利用时间切片离子速度成像技术在134∽140 nm波段研究了OCS分子经由F 31Π里德堡态的真空紫外光解离动力学. 在选取的5个分别对应OCS(F 31Π, v1=0∽4)的伸缩振动激发的光解波长,实验测得了来自CO(X1Σ+)+S(1D2)产物通道的SS(1D2))实验影像,并获得了总平动能谱和CO(X1Σ+, v)共生产物的振动布居及角分布. 结果分析表明OCS分子解离生成CO(X1Σ+)+S(1D2)产物的过程经历了上态F 31Π 与C?v和Cs构型的下电子态间非绝热耦合过程. 实验结果显示了很强的波长相关性:OCS (F 31Π, v1)的较低转动激发态(v1=0∽2)和较高转动激发态(v1=3, 4)的CO(X1Σ+)产物的振动布居和角分布具有显著差异,表明该解离过程中具有不同的解离机理. 本结果提供了振动耦合可能对真空紫外光解离动力学产生关键作用的相关证据. 相似文献
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boldmath B3Σu-–X3Σg- transition in selenium dimer: ab initio multireference configuration interaction calculations 下载免费PDF全文
Theoretical investigation of low-lying electronic states and B3Σu-–X3Σg- transition properties of selenium dimer using size-extensivity singly and doubly excitation multireference configuration interaction theory with nonrelativistic all-electron basis set and relativistic effective core potential plus its split valence basis set is presented in this paper. The spectroscopic constants of ten low-lying Λ-S bound states have been obtained and compared with experiments. Spin-orbit calculations for coupling between B3Σu- sates and repulsive 1Πu, 5Πu states have been made to interpret the predissociation mechanisms of the B3Σu- state. The lifetimes of B3Σu- (v=0~6) have been calculated with scalar relativistic effects included or excluded, respectively, and reasonably agree with experimental values. 相似文献
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The potential energy curves (PECs) are calculated for the 20 Λ-S states (X2Πg, A2Πu, B2Σ?g, a4Πu, b4Σ?g, b′4Πg, c4Σ?u, 12Σ+g, 12Σ+u, 12Σ?u, 14Σ+g, 14Σ+u, 14Δg, 14Δu, 16Σ+g, 16Σ+u, 16Πg, 16Πu, 24Πg and 24Πu) of O2+ cation and their corresponding 58 Ω states. Of these 20 Λ-S states, the 16Πu state is found to be repulsive. The 12Σ+g, 14Σ+u, c4Σ?u and 14Δu states are found to possess the double well. The b4Σ?g, 16Σ+g, 14Σ+u, a4Πu, A2Πu, 16Πg and 24Πg states are found to be inverted with the spin–orbit coupling effect included. The b′4Πg, 16Πg, 16Σ+g, 14Σ+u and 14Δu states, and the second well of the 12Σ+g state are found to be the weakly bound states. The b′4Πg state is found to possess one well with one barrier. The PECs are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction in combination with the aug-cc-pV6Z basis set. The core–valence correlation and scalar relativistic corrections are included. The convergent behaviour of present calculations is discussed with respect to the basis set and theoretical level. The spin–orbit coupling effect is accounted for. The PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated, and compared with available measurements. It demonstrates that the spectroscopic parameters reported here can be expected to be reliably predicted ones. 相似文献
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De-heng Shi Hui Liu Zun-lue Zhu 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(16):2567-2583
The potential energy curves (PECs) of the X3Σg−, D3Πu, a1Δg, b1Πu, H′3Σu−, K3Σu−, 13Σu+, 13Πg, 23Σu+, 23Πg, 33Πg, 33Σu+, 23Πu and 23Σg− electronic states of the Si2 molecule are investigated using the complete active space self-consistent field (CASSCF) method followed by the valence internally contracted multireference configuration interaction (MRCI) approach with the correlation-consistent basis sets of Dunning and co-workers. The effects on the PECs by the core-valence correlation and relativistic corrections are included. The way to consider the relativistic correction is to use the third-order Douglas-Kroll Hamiltonian approximation. The core-valence correlation correction is made with the aug-cc-pCV5Z basis set. And the relativistic correction is performed at the level of cc-pV5Z basis set. To obtain more reliable results, the PECs determined by the MRCI calculations are also corrected for size-extensivity errors by means of the Davidson modification (MRCI+Q). The PECs of all these electronic states are extrapolated to the complete basis set limit by the total-energy extrapolation scheme. Using the PECs, the spectroscopic parameters are determined and compared with those reported in the literature. With these PECs determined by the MRCI+Q/CV+DK+56 calculations, the vibrational levels and inertial rotation constants of the first 20 vibrational states are evaluated and compared with the RKR data for these electronic states when the rotational quantum number J equals zero. On the whole, as expected, the most accurate spectroscopic parameters and molecular constants of the Si2 molecule are determined by the MRCI+Q/CV+DK+56 calculations. And the spectroscopic parameters of the 13Σu+, 13Πg, 23Σu+, 23Πg, 33Πg, 33Σu+, 23Πu and 23Σg− electronic states obtained by the MRCI+Q/CV+DK+56 calculations should be good prediction for future laboratory experiment. 相似文献
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Potential curves for the four Hund's case (a) basis electronic states (2Σ, 2Πg, 2Πu, and 2Σ+) correlating with the I(2Pu) + I?(1Sg) dissociation limit have been calculated at the MRCISD level of theory using an all-electron double-zeta basis set augmented with an extensive set of polarization and diffuse functions complete through i angular momentum functions. Transition moments for the dipole allowed transitions between these states are determined as a function of internuclear separation. The four Hund's case (a) curves are used to determine the six Hund's case (c) potential curves which arise when spin-orbit coupling is considered. The rovibrational eigenvalues for each of these six states are determined numerically, and standard spectroscopic constants are determined by fitting the energy of these levels to a Duham series. The results are compared with available experimental and theoretical information. 相似文献
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利用圆偏振激光受激Raman抽运,以 C2H2分子为样品选择性地制备了它的电子基态单一转动态(X1Σ+g,ν″2=1,J″的角动量定向布居(orientation).并从圆偏振紫外激光诱导的A1Au(ν′3=1)←X1Σ+g(ν″2=1)的荧光(谱),直接测定了 C2H2(X1Σ+g,ν″2=1,J″=4,7,8,…,13)的角动量定向布居值.从时间分辨的荧光信号谱测定了角动量定向布居的碰撞弛豫速率常数,同时还研究了由各初始激励的转动态向其他邻近转动态碰撞诱导的角动量定向布居转移.
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Relativistic energy-consistent small-core lanthanide pseudopotentials of the Stuttgart-Bonn variety and extended valence basis sets have been used for the investigation of some selected lanthanide dimers with open 4f shell, that is Ce2, Pr2 and Gd2. Comparison is made with results of corresponding previous studies of La2 and Lu2 as well as to available experimental data. The trends in the molecular constants of the dimers of the lanthanide series are discussed. The ground state candidates of Ce2(4f14f1σ2 gπ4 u 1Σ+ g, 1Σ? u, 3Σ? g, 3Σ+ u, 16g, 36u) and Pr2(4f24f2σ2 gπ4 u 5Σ+ g, 5Σ? u, 510g) are degenerate within 20cm?1 and have the same valence subconfiguration σ2 g π4 u, which was previously found to give rise to the La2(4f04f0σ2 gπ4 u 1Σ+ g) ground state. In the case of Gd2 the 4f74f7σ2 gσ1 uσ2 u; 19Σ? g ground state found previously is confirmed. The derived molecular constants are the best theoretical estimates available at present and show a satisfactory agreement with experimental data. Discrepancies in the vibrational constants of La2, Ce2 and Pr2 are shown to be probably related to quite large Ar-matrix shifts. 相似文献
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Results of ab initio calculations of potential-energy curves for 20 singlet and 20 triplet valence states of oxygen with configuration interaction taken into account in the 6-31G basis are presented. Transition dipole moments of triplet-triplet (13Πg ← B 3Σ u ? , 13Πg ← A 3Σ u + , 13Πg ← A′ 3Δu, B 3Σ u ? ← X 3Σ g ? , 23Πu ← 13Π g, 23Σ g ? ← B 3Σ u ? , 13Πu ← X 3Σ g ? , 23Πu ← X 3Σ g ? , 23Π g ← A′3Δu, 33Πg ← A′ 3Δ u, 23Δu ← 23Πg, 33Πg ← B 3Σ u ? , and 23Πg ← A 3Σ u + ) and singlet-singlet (21Σ g + ← 21Πu, 21Πu ← 11Π g, 1Πu ← 21Δg, 11Πg ← c 1Σ u ? , 1Πu ← b 1Σ g + , 11Δ u ← a 1Δg, 21Πu ← a 1Δg, 21Δg ← 11Δu, 1Π u ← a 1Δ g, 11Πu ← b 1Σ g + , 21Πg ← 11Πu, 21Π g ← c 1Σ u ? , 11Δ u ← 11Π g, f′Σ u + ← b 1Σ g + , 21Σ g + ← f ′1Σ u + , 31Πg ← 11Δu) radiative transitions are calculated as functions of internuclear separation. The possibility of observing these transitions under experimental conditions is discussed. 相似文献
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Daniel D. Konowalow Marcy E. Rosenkrantz David S. Hochhauser 《Journal of Molecular Spectroscopy》1983,99(2):321-338
Electronic transition dipole moment functions based on ab initio multiconfiguration self-consistent field wavefunctions are computed for the transitions 1Σu+-1Σg+, 3Σg+-3Σu+, 1Πu-1Σg+, 3Πg-3Σu+, 1Σu+-1Πg, 3Σg+-3Πu, 1Πu-1Πg, and 3Πg-3Πu in Li2 and Na2. (In each case the states are the lowest lying of their symmetry.) We also calculate the matrix element 〈3Σu+|i(Lx - iLy)|3Πu〉 for the predissociation of the 3Πu state by the 3Σu+ state. Several unobserved spectral features are predicted. 相似文献