固态氮气基质中CO的红外光谱

CO单体在固体N2基质中在4．5—30K范围内的红外吸收光谱．基本的拉伸模式的吸收特征显示其基质诱导峰宽和位移呈现弱的温度依赖性．随着基质的温度升高，峰宽增加并且主要峰发生红移，这可能与在N2基质中CO旋转状态转变成近似于振动状态有关．并用定量模型计算振动态之间的能量差异．     

Analytical solution of the master equation with the transition probability derived from dynamical considerations

An exact relationship between the transition probability P(E → E^′) and quantum transition probabilities P_i→f of an active molecule under the effect of collisions with medium molecules is obtained. Treating an active molecule as a system of harmonic oscillators, it is possible to derive the analytical expression for P(E → E^′) from the “first principles” using the first-order perturbation theory for probabilities P_i→f. The only parameter of the model is expressed in terms of vibrational relaxation time that may be calculated numerically or taken from experiments. For the system of harmonic oscillators placed in a thermal bath, the solution of the master equation is found in the analytical form. An extended discussion of the model is also presented.     

Numerical studies of the vibrational isocoordinate rule in chalcogenide glasses

Many properties of alloyed chalcogenide glasses can be closely correlated with the average coordination of these compounds. This is the case, for example, of the ultrasonic constants, dilatometric softening temperature and the vibrational densities of states. What is striking, however, is that, at a given average coordination, these properties are nevertheless almost independent of the elemental composition. Here, we report on some numerical verification of this experimental rule as applied to the vibrational density of states. We find that this rule is not exact but holds qualitatively well over a wide range of compositions and local chemical correlations. Received 25 April 2000     

An infrared study of CD3CN in isopropanol, dimethyl formamide, and dimethyl sulfoxide

The vibrational characteristics of deuterated acetonitrile dissolved in isopropanol, dimethyl formamide (DMF), and dimethyl sulfoxide (DMSO) have been studied. Observed vibrational bands show substantial frequency shifts, the amounts of which vary almost linearly with concentration. The absorption feature in the region of 2220–2280 cm⁻¹ was deconvoluted to the consisting absorption bands. The band at 2258 cm⁻¹ of pure CD₃CN, which is on the low frequency side of the monomer CN stretch (ν₂), is attributed to the CN stretch of the dimer (ν′₂). The shoulder found on the further low frequency side of the ν₂ band, particularly in dilute solution, is believed to be due to ν₅, and its frequency and intensity vary largely as a function of concentration along with those of other vibrational bands involved with the CD₃ group. The ν₅ band of pure CD₃CN is believed to be active and located at about 2251 cm⁻¹. Ab initio calculations have also been performed for the solute–solvent complexes, CD₃CN–DMF and CD₃CN–DMSO, at the MP2/6-31+G(2d,p) level assuming anti-parallel configurations. The calculated results show a good agreement with the observed results.     

ClC(O)NCS分子振动光谱的理论研究

采用密度泛函理论DFT(B3LYP)方法,以6-31G^*为基组对ClC(O)NCS的反式和顺式两种构型的几何结构、振动谐性力场和红外光谱进行了研究.B3LYP/6-31G^*的理论力场由适用于B3LYP/6-31G^*计算水平和大多数有机分子的一套固定标度因子进行标度.根据标度后的理论力场进行简正坐标分析得到的势能分布(PED)和红外光谱强度值对ClC(O)NCS分子的顺式和反式两种构型的振动基频进行了理论归属.     

乙炔分子振动光谱的相互作用模式计算

应用量子自陷理论，发展了分子振动光变的相互作用模式方法，对Ｃ２Ｈ２与Ｃ２Ｄ２分子振动光谱进行了计算。计算结果与观测值很符合。     

Earth Alkaline Tetrathiosquarates. II. – Syntheses and Crystal Structures of SrC4S4·4 H2O and Ba4K2(C4S4)5·16 H2O

Concentrated aqueous solutions of strontium chloride and barium chloride, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄·H₂O, the isolation of the earth alkaline salts SrC₄S₄·4 H₂O ( 1 ) and Ba₄K₂(C₄S₄)₅·16 H₂O ( 2 ), both as dark red crystals. The crystal structure determinations ( 1 : orthorhombic, Pnma, a = 8.149(1), b = 12.907(2), c = 10.790(2) Å, Z = 4; 2 : orthorhombic, Pbca, a = 15.875(3), b = 21.325(5), c = 16.119(1) Å, Z = 4) show the presence of C₄S₄²⁻ ions with only slightly distorted D_4h symmetry having average C–C and C–S bond lengths of 1.41Å and 1.681Å for 1 and 1.450Å and 1.657Å for 2 . The structure of 1 contains concatenated edge‐sharing Sr(H₂O)₆S₂ polyhedra. The Sr²⁺ ions are in eight‐fold coordination with Sr–O distances of 2.50–2.72Å and Sr–S distances of 3.21Å, (C₄S₄)²⁻ acts as a chelating ligand towards Sr²⁺. The structure is closely related to the previously reported Ca²⁺ containing analogue, which is of lower symmetry belonging to the monoclinic crystal system. A supergroup‐subgroup relation between the space groups of both structures is present. The structure of 2 is made up of Ba²⁺ and K⁺ ions in eight and nine‐fold coordination by H₂O molecules and (C₄S₄)²⁻ ions which act as chelating ligands towards one cation and bridging between two cations. The coordination polyhedra of the cations are connected by common edges and corners in two dimensions to layers which are connected by tetrathiosquarate ions to a three‐dimensional network. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Vibrational wave analysis of infinite damaged beams using structure-borne power flow

In the view of structure-borne sound, vibrational wave analysis of infinite beam structures with a transverse open damage by means of vibrational power flow is investigated. In this paper, the damage is modeled as a joint of a local spring with a constant value that is deduced from the relationship between the strain energy and stress intensity factor in fracture mechanics, then the input power flow and transmitted power flow of perfect and dmaged beams are computed. The results show that the vibrational power flow of damaged beam is highly relative to the degree and location of damage.     

人工神经网络法预测四卤化物XY_4对称伸缩模和二重简并模的振动频率

用人工神经网络法，采用控制训练步长和两个惯性项的权重系数惯性调整法，分别用单目标和双目标的三层网络对四卤化物ＸＹ４的对称伸缩模。ｖ１和二重简并模ｖ２的振动频率进行了训练和预测，并将单双目标下预测的结果作了比较。双目标时发现［ＨｇＣｌ４］２的ｖ２振动频的计算值与实验值有很大差距，多目标优化可一定程度上避免过拟合。本文程序用ＦＯＲＴＲＡＮ语言编写，用ＮＤＰ－ＦＯＲＴＲＡＮ编译程序编译运行。     

Magnetic properties of a molecule in non-uniform magnetic field

Summary The potentials of the electromagnetic field in the Bloch gauge are used to obtain definitions for the multipole moment operators and for the operators expressing the electric and magnetic field of electrons acting on the nuclei of a molecule. Perturbation theory is employed to determine induced electronic moments and total electromagnetic field at the nuclei. A series of response tensors is defined to describe the contributions arising in non-uniform magnetic field and their origin dependence is studied.This paper is dedicated to Professor Werner Kutzelnigg on the occasion of his 60th birthday