Modeling of the vibrational structure of the vibronic spectrum and an excited state of the dinaphthylethylene molecule

The vibrational structure of the fluorescence spectrum and the structure of a dinaphthylethylene molecule in an excited state are calculated in the first and second approximations of the parametric method employed in the theory of vibronic spectra. The calculated spectra are in quantitative agreement with experimental data. The role of the angular parameters of the parametric method in the quantitative prediction of the vibrational structure of the fluorescence spectrum and changes observed in the geometry of the dinaphthylethylene molecule under excitation is determined. It is demonstrated that the polyene and acene parameters of the parametric method possess a high degree of transferability and that the models obtained are quite adequate to the real structures of the molecules under investigation. The proposed approach permits qualitative predictions and quantitative predictive calculations of the spectra of the studied molecules, as well as the spectral characteristics necessary for simulation of photochemical molecular transformations.     

EuC分子的电子态结构和稳定性理论研究

本文分别采用Gaussian98程序的密度泛函B3LYP方法和Gamess程序的CAS-MCSCF方法,研究了EuC分子的结构问题.两种方法均得到了12重态是EuC分子的基态的结论.基于B3LYP方法,得到12∑+态的LUMO和HOMO能量差达到3.689 eV,明显的高于其他多重度的结果.基于MCSCF方法的结果显示,需要进一步的考虑相对论效应修正以及增大活性空间的尺寸将会得到对高自旋电子态更为可靠的结论.     

电子的交换作用对激发态能量的影响

根据作者提出的物理模型和简洁有效的计算方法,考虑电子交换应对于激发态的影响,计算了激发态Ｌｉ原子（１ｓ＾２４ｓ）＾２Ｓ１／２的能量。计算结果表明：电子的交换能对低激发态的贡献较大,而对较高激发态（５ｓ、６ｓ…以上）在计算过程中可以忽略不计。     

咔唑分子拉曼激发虚态的相关研究

根据键极化率与拉曼峰强之间的关系,得到咔唑分子拉曼激发虚态随时间演化的键极化率. 将得到的键极化率的末态与用密度泛函理论得到的基态键电荷密度进行了对比,讨论并分析了拉曼激发虚态键极化率随时间弛豫的特征. 研究表明:咔唑分子在拉曼激发初态时,电子由两个骨架六元环向连通两六元环的连通键上流动,而并非向外围的C–H键上流动. 拉曼激发末态键极化率分布趋势与基态键电荷密度分布很相似,说明激发的电子又流回到分子骨架,即弛豫到基态. 通过对拉曼激发虚态键极化率弛豫过程特征时间的研究,发现连通两六元环的C–C键以及靠近连通键的C–C键的键极化率的弛豫时间较其他键的极化率弛豫时间都长,进一步说明了拉曼激发虚态电子弛豫特征. 这些结果反映了咔唑这类具有连通键的多元环分子在拉曼激发虚态所具有的特征与性质,这对拉曼激发虚态的研究有重要意义. 关键词： 拉曼峰强 键极化率 拉曼激发虚态     

Vibrational resonances of non-rotating HCN in the excited electronic state

A multi reference internally contracted configuration interaction (MRCI) method is used to generate the potential energy function (PEF) of the excited electronic state of HCN molecule. The analytic representation of the PEF is employed to calculate complex eigenvalues (resonance positions and widths) by a discrete variable representation (DVR) of the Hamiltonian for the non-rotating (J =0) molecule. The computational method used is a variant of the filter-diagonalization technique based on a recursive polynomial expansion of the absorbing-boundary-conditions (ABC) Green operator. Reasonable agreement with existing experimental data is found. Received 27 July 1999 and Received in final form 18 October 1999     

Multipole corrections to the electronic terms of a highly excited molecule

The properties are investigated of the electronic terms of a molecule with one of its electrons highly excited. These terms have a form similar to the ground electronic term of the corresponding molecular ion (core), and are obtained in the zeroth approximation by a parallel downward shift equal to Ry/n₂ and independent of the internuclear distances (symbasis property). The main causes of the deviation from this property are discussed. The nonsymbatic corrections, necessitated by the multipole interaction of the Rydberg electron with the ion core, are discussed. The possibility of using the results to detect new exciplexes is indicated.Translated from Trudy Fizicheskogo Instituta im. P. N. Lebedeva, Vol. 120, pp. 107–119, 1980.     

The electronic structure of the S8 molecule

The UV and X-ray photoelectron spectra of the S₈ molecule are presented together with an SCF-Xα-SW calculation of the electronic structure. The calculated optical transition energies are also presented and compared with the experimental UV absorption spectrum.     

激发态分子内质子转移有机分子HBT的三阶非线性光学特性

以532nm皮秒脉冲作抽运光,采用单光束Z-扫描技术对具有激发态分子内质子转移效应的有机分子2-(2′-羟基苯基)苯并噻唑(HBT)在其双光子吸收区的非线性光学特性进行了研究.实验结果表明,对532nm波长的光,HBT分子存在明显的双光子吸收.通过拟合开孔Z-扫描实验数据,求解了HBT分子在其双光子吸收区的非线性吸收系数,并探讨了抽运光强度对介质双光子吸收效应的影响.采用高斯分解法,通过拟合闭孔Z-扫描除以开孔Z-扫描数据,理论推导并计算了在介质对抽运光存在非线性吸收的情况下HBT分子的非线性折射率,以及不同入射光强度时HBT分子的三阶非线性极化率实部和虚部的值.计算结果表明,理论分析与实验结果较好地符合,这些结果为进一步研究和开发此类材料的应用提供了理论与实验依据.     

The KrXe molecule: Modification of potential curves of the ground and first excited electronic states

Potential curves of the ground state of the KrXe molecule and its excited states that converge to the Kr(4p ^{6 1} S ₀) + Xe(5p ⁵6s ³ P ₁) atomic states are corrected and tested using the results of modeling published vacuum ultraviolet spectra of a gas-discharge plasma of a krypton/xenon mixture.     

Determination of dunham coefficients and calculation of the energies of highly excited vibrational-rotational levels of the carbon monoxide molecule in the electronic ground state

The values of Dunham constants are calculated for the electronic ground state of the carbon monoxide molecule on the basis of new values of the effective rotational and centrifugal constants and the energies of the high vibrational-rotational states are predicted. The peculiarity of the approach consists in the use of vibrational-rotational levels computed according to the traditional polynomial equation of energy values as the initial data for the procedure of Dunham coefficients determination. The role of the maximum degree of the Dunham polynom in determining its coefficients is analyzed, and the energy levels up to ν = 40 and J = 60 are calculated. A comparison with the literature data is made.     

Vibronic state specific predissociation rates from excited electronic states

It is shown that predissociation can be perceived as a primary process due to the continuum part of a Morse oscillator potential. In the model proposed here internal conversion to the ground state is thus not necessarily the primary process of a consecutive dissociation but may be a simultaneous decay. As a consequence, dissociation rates should show strong variations from specific (ro-) vibrational states of the first excited electronic states that are similar to those known from “pure” internal conversion rates. This behaviour is demonstrated by calculating predissociation rates for the process. Especially the out-of-plane modes seem to play an extraordinary role in the excess energy behaviour of the predissociation rate. At lower excess energies, rates from single vibronic levels with out-of-plane mode characteristics may show an increase by several orders of magnitude. Received: 13 November 1998     

电场对分子线电子结构的影响

从第一性原理出发,利用密度泛函理论计算了分子2-氨基-5-硝基-1,4-二乙炔基-4-苯硫醇基苯与金原子团形成的分子线的电子结构,从轨道、能级及吸附电子三个方面讨论了电场对分子线电子结构的影响.该工作将有利于未来纳米电子学器件的设计.     

The electronic structure of an H-center

The electronic structure of a new type of color center, which is produced in KCl, KBr, and LiF crystals by X-irradiation at low temperatures, has been determined by electron-spin-resonance experiments. Crudely, this center can be described as a halogene⁻₂ molecule-ion located in a halide-ion vacancy. The unpaired electron interacts strongly with the two nuclei of the moleculeion and weakly with two more halogen nuclei. All four nuclei lie in a straight row along a [110] axis. This paramagnetic center may be identical with the center that gives rise to the optical H-band, since in KCl it has the same production, bleaching, and symmetry characteristics.     

The evaluation of temporal electronic structures of nonresonant Raman excited virtual state of thiourea

An algorithm has been introduced to calculate molecular bond polarizabilities of thiourea, which supply essential electronic information about the nonresonant Raman excited virtual states. The main dynamical behaviour of the excited virtual states of thiourea is that the Raman excited electrons tend to flow to the N-H bonds and C-N bonds from the S-C bonds because of the electronic repulsion effect. The difference in Raman excited electron relaxation time of thiourea under 514.5-nm and 325-nm excitations has been observed, which quantitatively shows that the Raman scattering process is dependent on the wavelength of the pumping laser. Finally, the distribution of the electrons at the final stage of relaxation is given out through the comparison between the bond electronic densities of the ground states and the bond polarizabilities after deexcitation.     

Doublet structure of the first excited state of 71As

The possible multiplet structure of the first-excited state of ⁷¹As has been investigated by the high resolution ⁷⁰Ge(³He, dγ) reaction and the γ-rays emitted in the decay of ⁷¹Se. Both studies reveal a doublet at 143.2 keV and 147.3 keV excitation energies. The existence of this doublet in ⁷¹As brings the low-lying level structure in better resemblance to the heavier odd-A arsenic isotopes.     

Polarization spectroscopy of an excited state transition

We demonstrate polarization spectroscopy of an excited state transition in room-temperature cesium vapor. An anisotropy induced by a circularly polarized pump beam on the D2 transition is observed using a weak probe on the 6P(3/2)→7S(1/2) transition. At high pump power, a subfeature due to Autler-Townes splitting is observed that theoretical modeling shows is enhanced by Doppler averaging. Polarization spectroscopy provides a simple modulation-free signal suitable for laser frequency stabilization to excited state transitions.