Charge Transfer Bands of Mixed Valence Molecular Crystals

The electron-vibrational (vibronic) bands of light absorption by mixed valence molecular crystals containing clusters of transition metal ions in different states of oxidation as the structural units of lattice are considered. The absorption band shape calculation in different phase states is performed in the semiclassical limit for crystals consisting of trielectronic clusters of transition metals of the type of d¹-d². The band shape differs from the Gaussian and closely depends on the double-exchange and Heisenberg-type exchange parameters and on the temperature dependence of the average dipole moment playing the role of the order parameter.     

Thermodynamic Properties and Molecular Dipole Moments of Antimony Compounds from Quantum Chemical Evaluations

By the PM3 method, standard values of entropy, heats and Gibbs energies of formation and dipole moments of the molecules have been computed for a series of inorganic and organic antimony compounds. Linear dependences P exper = bP theor (where P is any of the mentioned properties) have been stated, allowing a priori evaluation of thermodynamic characteristics and molecular dipole moments of Sb-containing substances. It has been concluded that triphenylstibinedichloride in benzene solution, as well as triphenylstibinehydroxychloride in dioxane medium, exist in the form of trigonal bipyramid with two axial chlorine and oxygen atoms.     

单模辐射场作用下两二能级原子的Wigner－Yanase偏态信息

研究了与单模辐射场作用过程中两二能级原子的Wigner －Yanase信息。结果表明：两原子总Wigner－Yanase偏态信息依赖于处于基态｜gg>，第一激发态（｜eg>＋｜ge>）／2和第二激发态｜ee>的概率。由于光场的作用， Wigner－Yanase偏态信息呈现出周期性的丢失与恢复现象，但原子间的偶极－偶极相互作用对Wigner－Yanase信息的丢失有阻抗作用。     

Inverse grand-canonical Monte Carlo investigation of the activity coefficient of polar fluids

The inverse grand-canonical Monte Carlo (IGCMC) simulation is applied to calculate the activity coefficient of polar fluid. Molecules of the fluid are represented by hard spheres with a point electric dipole moment immersed in the centre. The electron polarizability of the fluid is described by the permittivity ?_∞. Good agreement between the IGCMC technique and Widom method data is obtained. Comparison with the results of the mean spherical approximation shows that this theory underestimate the Coulombic interactions while the agreement with PT is good. The dependence of the activity coefficient on the number density, electric dipole moment, molecular diameter, and temperature is presented. The Coulombic contribution to the activity coefficient is separated.     

Analytic solution of the wave equation for an electron in the field of a molecule with an electric dipole moment

We relax the usual diagonal constraint on the matrix representation of the eigenvalue wave equation by allowing it to be tridiagonal. This results in a larger representation space that incorporates an analytic solution for the non-central electric dipole potential cosθ/r², which was believed not to belong to the class of exactly solvable potentials. Therefore, we were able to obtain a closed form solution of the three-dimensional time-independent Schrödinger equation for a charged particle in the field of a point electric dipole that could carry a nonzero net charge. This problem models the interaction of an electron with a molecule (neutral or ionized) that has a permanent electric dipole moment. The solution is written as a series in a basis composed of special functions that support a tridiagonal matrix representation for the angular and radial components of the wave operator. Moreover, this solution is for all energies, the discrete (for bound states) as well as the continuous (for scattering states). The expansion coefficients of the radial and angular components of the wavefunction are written in terms of orthogonal polynomials satisfying three-term recursion relations. For the Coulomb-free case, where the molecule is neutral, we calculate critical values for its dipole moment below which no electron capture is allowed. These critical values are obtained not only for the ground state, where it agrees with already known results, but also for excited states as well.     

Measurements of line intensities and determination of transition moment parameters from experimental data for the ν1 and ν3 bands of D2S

First measurements of line intensities for ν₁ and ν₃ bands of D₂³²S are reported. About 300 intensities of D₂³²S vibration–rotation lines were obtained from experimental high-resolution spectra recorded in the 1810–2051 cm⁻¹ region with the Fourier Transform Spectrometer built in Reims. Empirical values of transition moment parameters for ν₁ and ν₃ bands of D₂³²S were determined for the first time using a least-square fit to the observed intensities. Experimental D₂³²S intensities were compared with recent global variational predictions [Vl.G. Tyuterev, L. Régalia-Jarlot, D.W. Schwenke, S.A. Tashkun, Y.G. Borkov, C. R. Phys. 5 (2004) 189–199] computed from isotopically invariant potential and dipole moment functions of the hydrogen sulphide molecule. Average discrepancy between these calculations and our observed data was 0.03 cm⁻¹ for line positions of this spectral range. The discrepancy between these calculations and our measurements for the sum of line intensities was 5.5% and 3.5% for the ν₁ and ν₃ bands, correspondingly.     

A mathematical-physics approach for studying far-infrared absorption in structurally disordered solids

A rigorous analysis is performed in order to characterize the mathematical structure of the integrated coefficient of optical absorption corresponding to structural disorder in amorphous solids. In this approach, the integral of the aforementioned coefficient is considered for the low region of the far-infrared range. Two basic ingredients in our formulation are the dipole-moment matrix element and phonon density of states.     

Dielectric properties of 1,1,1-trifluoroethane (HFC-143a) in the liquid phase

The relative permittivity (?_r) data of 1,1,1-trifluoroethane (HFC-143a), (CAS N# 420-46-2), a hydrofluorocarbon (HFC) developed as a refrigerant that has zero ozone depletion potential, is reported. The relative permittivity of HFC-143a in the liquid phase was measured using a direct capacitance method at temperatures from T = 218 to 294 K and at pressures up to P = 15 MPa, for a frequency of 10 kHz. The uncertainty of the ?_r measurements is estimated to be better than ±1.2 × 10⁻². A complete set of tables of experimental data as a function of temperature, pressure and density, is presented that covers the dielectric property needs for most engineering applications. To study the dependence of ?_r on density and temperature on a molecular basis, the theory developed by Vedam et al. and adapted by Diguet was applied to analyse the data. The Kirkwood modification of the Onsager equation was used to obtain the value of its dipole moment in the liquid phase (μ*). The apparent dipole moment obtained was μ* = 3.293 D. The effective dipole in the liquid state predicted by the Kirkwood–Frölich theory is 2.530 D. The measured values are compared with density functional and density functional self-consistent calculations (SCIPCM) of the electronic distribution and of the dipole moment of HFC-143a. Finally, the values of the isobaric thermal expansion and isothermal compressibility were estimated from the reported measurements.     

Computational molecular characterization of Coumarin-102

In this work, we make use of a model chemistry within Density Functional Theory (DFT) recently presented, which is called M05-2X, to calculate the molecular structure of 8-methyl-2,3,5,6-tetrahydro-1H,4H-11-oxa-3a-aza-benzo(de)anthracen-10-one (Coumarin-102), as well to predict its infrared (IR), ultraviolet (UV–vis) and fluorescence (Fluo) spectra, the dipole moment and polarizability, and the HOMO and LUMO orbitals as a possible indication of its usefulness for Organic Photovoltaics applications.