S2分子B″3Πu态的势能函数和光谱常数的理论研究

推导了S₂分子B″³Π_u态的合理离解极限.用Gaussian 94 QCISD(T)方法和6-311++G^**基组计算了S₂分子B″³Π_u以及X³Σ^-_g态的势能曲线.给出了S₂分子B″³Π_u态的Murrell-Sorbie势能函数和光谱常数.B″³Π_u与B³Σ^-_u态在排斥支重叠范围大；同时，B″³Π_u与X³Σ^-_g态有相同离解极限，因而，在吸引支有重叠.讨论了B″³Π_u与B³Σ^-_u和X³Σ^-_g态相互作用的特征. 关键词：     

Na2O-Al2O3-P2O5系统玻璃中的[Al-O-P]-基团

本文报道Na₂O-Al₂O₃-P₇O₅系统玻璃中[Al-O-P]^-基团的Raman谱。我们把高频峰有规律地移向低波数归结为由[Al-O-P]^-基团构成的玻璃网络聚合度下降造成。 关键词：     

分子部分电子态的高阶振动能级和离解能的精确研究

鉴于K₂分子电子态的振动能谱和分子离解能D_e在实际研究和应用中的重要性,应用Sun,Ren等人提出的基于微扰理论的代数方法(AM)和基于AM的代数能量方法(AEM)研究了K₂分子的X¹Σ⁺_g,a³Σ⁺_u,0^-_g,B¹Π_{u< 关键词： 2}分子')" href="#">K₂分子 代数方法 高阶振动能级 离解能     

β-衰变中容许跃迁和禁戒跃迁的衰变规律

在考虑容许跃迁和禁戒跃迁的基础上, 对远离β稳定线附近原子核的β^-衰变寿命进行了系统的研究, 发现对于远离β稳定线的原子核的β^-衰变寿命, 其容许跃迁和禁戒跃迁寿命(T_1/2)与母核的质子数和中子数之间存在指数规律. 利用这个规律, 计算了β^-衰变中的容许跃迁和禁戒跃迁(包括一级禁戒跃迁和二级禁戒跃迁)的衰变寿命, 理论计算结果与实验值符合得很好. 在此基础上, 对于一些核素的β^-衰变寿命进行预言, 这对于核物理和天体物理中β^-衰变研究具有重要意义.     

NO分子b~4Σ~-—a~4Π_i(4,0)带的吸收光谱

通过对NO与He流动混合气体放电,产生了激发态的NO(a⁴Ⅱ_ii)分子.利用光外差-浓度调制吸收光谱技术测量了NO分子在12530-12850 cm^-1波段内的吸收光谱,并标识出b⁴∑^--a⁴Ⅱ_i（4,0）带在该波段内的324条跃迁谱线.采用标准⁴∑^-—⁴Ⅱ_i哈密顿量模型,通过非线性最小二乘法拟合其中267条谱线,拟合残差(0.0071 cm^-1)接近实验系统测量误差(0.007 cm^-1).获得的主要分子常数与文献提供的常数符合,并且拟合得到了精细结构分子常数.     

少量KCl引起水杨酸表面增强喇曼散射谱的异常变化

本文报道KCl引起的银胶中水杨酸(C₇H₄O₃)表面增强喇曼散射谱(SERS)的异常变化。发现KCl造成水杨酸分子中某些结构的SERS强度急剧而迅速下降,但同时又造成3436cm^-1附近v(—OH)振动的SERS信号的进一步增强。还研究了KCl对一系列含—COOH结构的分子(例如苯甲酸、对氨基苯甲酸等)SERS信号的影响,发现Cl^-对v(—COO^-)振动的SERS强度有明显的 关键词：     

75As32S+和75As34S+离子的光谱常数与分子常数

采用内收缩多参考组态相互作用(MRCI)方法, 结合Dunning系列相关一致基, 分别对⁷⁵As³²S⁺和⁷⁵As³⁴S⁺离子的X³Σ^-和A¹Π电子态的势能曲线进行了计算, 进一步拟合势能曲线, 得到各电子态的光谱常数与分子常数. 首先, 采用MRCI方法结合相关一致基, aug-cc-pV5Z, 对AsS⁺离子的X³Σ^-和A¹Π 电子态进行了计算, 获得相应的势能曲线; 然后, 为进一步提高势能曲线的精度, 对其进行了三种修正计算. 采用Davidson(+Q)方法修正MRCI 方法计算过程中存在的基组大小不一致缺陷; 利用二阶Douglas-Kroll哈密顿近似, 在cc-pVQZ基组水平, 修正了相对论效应对势能曲线的影响; 利用两点能量外推法, 在aug-cc-pVQZ和aug-cc-pV5Z基组水平对各能量点的势能值进行了外推, 得到完全基组极限处的势能曲线. 最后, 利用修正(包括Davidson修正、相对论修正和基组外推)后的势能曲线, 通过Vibrot程序, 求解双原子分子核运动的径向Schrödinger方程, 并进行同位素质量识别, 得到⁷⁵As³²S⁺和⁷⁵As³⁴S⁺离子两个电子态的光谱常数(T_e, R_e, ω_e, ω_ex_e, α_e 和B_e)和分子常数(G(ϒ), B_v, D_v).     

Li2B4O7晶体的晶格振动光谱

在室温下测量了Li₂B₄O₇单晶的各种振动类的偏振Raman散射谱和该晶体粉末样品的红外吸收谱(200—4000cm^-1)。根据LO-TO劈裂的实验结果,计算出该晶体极化模的有效电荷和振子强度。通过与BBO和LBO晶体的结构和B—O伸缩振动模频率比较,得出:Li₂B₄O₇晶体可能有较大的非线性光学系数。 关键词：     

PuO分子X5Σ-态的势能函数及热力学函数的量子力学计算

在Pu的相对论有效原子实势近似和O原子6-311G^*全电子基函数下,用quadratic configuration interaction of singlely and doublely substitution(QCISD)方法计算了PuO分子基态X⁵Σ^-的Murrell-Sorbie解析势能函数和热力学函数,得到R_e,D_e,B_e,α_e,ω_关键词：     

K3Ba3C60在不同温度下的Raman光谱研究

研究了K₃Ba₃C₆₀在不同温度下的Raman光谱.发现Raman光谱随温度的变化发生有规律的变化.随着温度的降低,所有模的线宽和强度的变化情况与纯的C₆₀的情况明显不同.径向Ag(2)模的频率在20K到室温之间有一个反常大的向高频漂移(9cm^-1),这表明在C₆₀分子和掺杂离子之间存在着轨道杂化.另外Raman光谱中Ag(1)模两个分量的相对强度随着温度的降低发生有规律的变化. 关键词： 高频漂移 轨道杂化     

KZnF3:Cr3+和KMgF3:Cr3+四角对称电子顺磁共振参量与晶格缺陷的研究

用Newman叠加模型研究了KZnF₃:Cr³⁺四角对称基态的零场分裂,证实了Zn²⁺空位和畸变的存在;并指出,空位对晶场的贡献不可忽略。计算得到:KZnF₃:cr³⁺晶体[0,01]方向的一个F^-配体向Cr³⁺移动Δ(KZnF₃)=0.0029-0.0043nm。还研究了KMgF₃:Cr^{3+关键词：}     

The use of electron impact dissociation and the photon-photon cascade technique to measure the lifetime of the B2Σ+ state of CN

The lifetime of the (B³Σ⁺_{υ= 0, 1} state of the CN radical has been measured by the photon-photon delayed coincidence technique, the CN radical being produced by electron impact dissociation of acetonitrile. This is the first lifetime measurement in a free radical by this method. The optical cascade in the band spectrum of CN used for the present measurement is H²Π_r - B²Σ⁺ - X²Σ⁺. The lifetime of the (B²Σ⁺)_{υ=0, 1} state in CN has been found to be 61.1 ± 7.6 ns.     

Preferential orientation of planar Ni(CN)2-4 complex ions in a NaCl lattice: Evidence from EPR studies

Anomalous intensity distribution in the EPR spectrum from tetragonal [Ni(CN)₄.Cl₂]^5- complex in γ-irradiated NaCl:Ni(CN)^2-₄ has been observed. A detailed EPR study revealed that the planar Ni(CN)^2-₄ complex preferentially enters the lattice with the plane parallel to the {100} growth planes of the crystal. Consequently, regions in the crystal could be found where the complex ions are predominantly oriented parallel to one of the three {100} planes of the crystal. Possible mechanisms of incorporation of the ions are discussed.     

Photophysical studies of uranyl complexes 5. Luminescence spectrum of K4UO2(CO3)3

The photoluminescence of K₄UO₂(CO₃)₃ has been studied under conditions of high resolution at cryogenic temperatures. The origin corresponding to the pure electronic transition was located at 4774 Å (20945 cm^-1), and it was found that the totally symmetric uranyl stretching mode was coupled to this transition. A progression of four band systems thus resulted, and from an examination of the energies of corresponding peaks in each system, a value of 813 cm^-1 for the U-O stretching mode was determined. Two lattice modes (34 and 80 cm^-1) and two molecular vibrational modes (205 and 276 cm^-1) were also found to couple with the pure electronic transition, thus yielding approximately 15 major peaks in each band system. The 205 cm^-1 vibration corresponded to a CO^2-₃ vibration, while the 276 cm^-1 vibration was a UO²⁺₂ deformation. The low values obtained for the force constant and totally symmetric stretching frequency of the U-O bond suggested that in UO₂(CO)^4-₃, the uranium atom is bound in a complex species that may be considered as an intermediate between that of a uranyl (UO²⁺₂) and a uranate (UO^10-₈) ion.     

The vibrational spectra of some isotopic species of propionitrile

The infrared and Raman spectra of CH₃CH₂CN, CH₃CD₂CN, and CD₃CH₂CN, and the infrared spectrum of CH₃CH₂¹³CN were investigated in detail between 6000 and 100 cm⁻¹. Some infrared measurements of other isotopic species are also reported and partial assignments given. All fundamentals of propionitrile-d₀, -d₂, -d₃, and -¹³CN were assigned, together with a large number of mainly binary combination bands for which a general method of assignment is given. Several Fermi resonances were detected and the unperturbed positions of some of the levels involved were calculated. Special attention was paid to the CH stretching vibrations for which persisting wrong assignments exist in the literature, and to the methyl torsion frequencies which were determined for the four isotopic species above. A valence force field was calculated, and the potential energy distribution of the normal vibrations is tabulated.     

Fluorescence from the 2B1 state of NO2 excited at 4545 Å

The 4545 Å line of the Ar⁺ laser has been used to excite a ^pR₁ line of a vibrational band of the ²B₁-²A₁ system of nitrogen dioxide. Fluorescence from the upper level to the ground electronic state forms a long progression in the bending vibration. This progression can be followed from v″₂ = 0 up to v″₂ = 12, and the fluorescence intensity passes through several local minima as a function of v″₂. The main features of the intensity distribution can be reproduced using a model Hamiltonian which separates the bending and rotation from the stretching vibrations. This Hamiltonian can also be used to reproduce the fluorescence frequencies by adjusting the potential function of the lower state.     

An optical study of the stretching absorption band near 3 microns from OH- defects in LiNbO3

A near infrared absorption band (λ = 2.87 μ), identified as the 0–1 stretching vibrational band of OH^- defects in LiNbO₃, has been observed at 6, 77, and 300 K. This band was completely polarized perpendicular to the crystallographic c-axis within experimental error and two peaks, separated by approximately 13 cm^?1, were resolved. Both the structure and optical anisotropy of this band were independent of stoichiometry and sample treatments and may be understood in terms of a simple model where protons are captured by O^2- anions forming OH^- defects whose orientations are determined by neighboring O^2- ions.     

The properties of five highly conducting salts: (TMTSF)2X, X = PF6-, AsF6-, SbF6-, BF4- and NO3-, derived from tetramethyltetraselenafulvalene (TMTSF)

The properties of five new highly conducting salts of TMTSF, (TMTSF)₂X, X = PF₆^-, AsF₆^-, SbF₆^-, BF₄^- and NO₃^- are reported. The measurements include d.c. and m.w. conductivity, thermopower, optical reflectivity, magnetic susceptibility and ¹⁹F-NMR. Preliminary structural data indicate uniform donor stacks. Metal to insulator transitions in four materials occur below 20 K, where specific conductivities higher than 10⁵ (Ω-cm)^?1 are observed for two salts (X = PF₆^- and NO₃^-).     

LiF-LiCl-B2O3系统非晶态快离子导体结构的研究

本文通过对¹¹B核磁共振(¹¹B-NMR)、红外光谱等实验方法,研究了LiF-LiCl-B₂O₃三元系统玻璃的结构和离子导电性,着重于F^-离子在玻璃网络中所起的作用,以及F^-,Cl^-和Li⁺离子对导电率的影响。LiF-LiCl-B₂O₃三元系统玻璃,随LiF含量的增加,B由三角体向四面体变化,从而F^-离子进入网络,使玻璃结构由[B₂O₃]三角体层状结构向三维空间延展,形成了含有[BO₃F]基团的三维空间网络,Cl^-离子以游离的离子存在于网络中,起着松散网络的作用,对提高电导率有利,而Li⁺离子作为传导离子,对电导率的贡献是主要的。本系统玻璃的电导率是随LiF,LiCl含量的增加而增大,在300℃时测得电导率σ=6.12×10^-4Ω^-1·cm^-1。 关键词：