Force Constants and Mean Amplitudes of Vibration of the Thiazyl Halides Cisn and BrSN

The force constants have been calculated for thiazylnalides CISN and BrSN employing general valence force field and Urey-Dradley force field. The computed results show some interesting features. The mean amplitudes of vibration have also been calculated at temperatures, O°K, 298.15°K and 500°K. These results will be helpful for the interpretation of the electron diffraction data whenever available.     

Effect of Environmental Cations on Force Constants,Vibrational Mean Amplitudes and Bond Order of Metaloxygen Bonds in Some Octahedral Oxyanions

The general valenoe force field (GVFF), modified orbital valence force field (MOVFF), and modified Urey-Bradley force field (MUBFF) have been employed to calculate the force constants of octahedral Te⁶⁺o₆, and Ti⁴⁺o₆ anions in the presence of different environmental cations. The mean amplitudes and generalized mean square amplitudes of vibrations for these anions at temperatures; O°K,298. 16°K, and 500°K have also been calculated. Further, the metaloxygen bond order was estimated with the help of general valence stretching force constants. The effects of environmental cations on the force constants, mean amplitudes and π-bonding of metal-oxygen bonds have been critically discussed. The effect of atomic masses of anions on the ooriolis coupling constants of ‘f_iu species has also been outlined.     

Harmonic Force Field and Mean Amplitudes for Gallium Tribromide and Triiodide Dimers

Harmonic force fields are developed for the Ga₂Br₆ and Ga₂I₆ molecules. The analysis confirms previous assignments of experimental frequencies. Mean amplitudes of vibration are calculated.     

Harmonic Force Fields and Mean Amplitudes for Aluminum Triiodide Dimer and Monomer

Harmonic force fields for AlI₃ (in-plane) and Al₂I₆ are developed from incomplete experimental assignments of vibrational frequencies and comparison with related molecules analysed previously. The missing frequencies are predicted from the calculations. Mean amplitudes of vibration are calculated.     

Harmonic Force Fields and Mean Amplitudes for Aluminum Trifluoride Monomer and Dimber

Recently, in this Journal, J. D. Macomber¹ has inquired into the mechanisms by which a signal is produced in a crossed-coil NMR spectrometer, His reflections led him to question the conventional explanation and to propose in its place a novel and more subtle one. The claim is made that the crossed-coil instrument is unique in its performance of a special form of emission spectroscopy-the detection of coherent spontaneous radiation (superradiance).² It is important to question fundamentals; however, we must disagree with the author's conclusions.     

Harmonic Force Fields and Mean Amplitudes For Gallium And Indium Trihalide Monomers

Harmonic force fields (in-plane) for gallium and indium trihalides are developed from complete or incomplete experimental assignments of vibrational frequencies. The missing frequencies are predicted from the calculations Mean amplitudes of vibration are calculated.     

Vibrational Mean Amplitudes of XY3 Pyramidal Molecules

The vibrational mean amplitudes for bonded as well as for nonbonded distances have been evaluated for AsP₃, SbP₃, and PAs₃ at temperatures : T = 0^oK, T = 298.15^oK and T=500 ^oK using recent vibrational data. The results have been briefly discussed.     

Mean Amplitudes of Vibration for Some Linear Gold(I) Complexes

Recently, Braunstein and Clark¹ described the synthesis and vibrational spectra of complexes containing the AuCl₂, AuBr² and AuI₂ ions. In order to obtain a deeper insight into the vibrational properties of these anions it seems interesting to calculate, using the available spectroscopic data, values for the mean amplitudes of vibration and some related quantities.     

Geometric Mean of States and Transition Amplitudes

The transition amplitude between square roots of states, which is an analogue of Hellinger integral in classical measure theory, is investigated in connection with operator-algebraic representation theory. A variational expression based on geometric mean of positive forms is utilized to obtain an approximation formula for transition amplitudes.     

The GVFT Force Constants for PO4 3-/Td/

The force constants for the tetrahedral PO₄ ^3- ion have been calculated on the basis of the general valence force field with the application of the Wilson FG matrix method^1,2.     

A New Determination of the Lambda-Nucleon Coupling Constants in Relativistic Mean Field Theory

A new determination of the Lambda-nucleon coupling constants in relativistic mean field theory is presented by optimizing both hyperon binding energy and spin-orbit splitting.Hypernuclear single particle spectra with the new coupling constants suggest the good agreement between the calculation and available data.The spin-orbit splitting of hyperon in medium mass hypernuclei is systematically larger than that in light-or heavy-mass hypernuclei.The sensitivity of the Lambda spin-orbit splitting to the omega-Lambda-Lambda tensor coupling term is also explored.     

A New Determination of the Lambda-Nucleon Coupling Constants in Relativistic Mean Field Theory

A new determination of the Lambda-nucleon coupling constants in relativistic mean field theory is presented by optimizing both hyperon binding energy and spin-orbit splitting. Hypernuclear single particle spectra with the new coupling constants suggest the good agreement between the calculation and available data. The spin-orbit splitting of hyperon in medium mass hypernuclei is systematically larger than that in light- or heavy-mass hypernuclei. The sensitivity of the Lambda spin-orbit splitting to the omega-Lambda-Lambda tensor coupling term is also explored.     

由QCD求和规则计算π介子和K介子twist-3分布振幅的归一化常数

本文用QCD求和规则计算了π介子和K介子的两个twist-3分布振幅的归一化常数m_{0π}^p和m_{0K}^p. 与运动方程的要求不同, 我们的计算结果表明(把求和规则微扰部分的α_s修正考虑之后), m_{0π}^p=1.00±0.17GeV,m_{0K}^p=1.46±0.23GeV. 应该指出的是, 它们与运动方程给出的结果相比要小不少. 比如π介子的情形, QCD求和规则给出的上述结果约是运动方程要求的值的50%左右.在exclusive的一些过程中, 人们发现, 一直到Q²较大(2—40GeV²)的区域,本应受到抑止的非首要的(比如, non-leading twist的贡献)贡献还可以跟首要的贡献(比如, leading twist的贡献)相比, 甚至可以超过. 这是难以相信的. 而较小的归一化常数将有助于弱化这个矛盾. 我们的计算结果支持这一点.     

Review of AdS/CFT Integrability,Chapter V.3: Scattering Amplitudes at Strong Coupling

Letters in Mathematical Physics - We review the computation of scattering amplitudes of planar maximally super-symmetric Yang–Mills at strong coupling. By using the AdS/CFT duality the...     

B3LYP Calculation of Deuterium Quadrupole Coupling Constants in Molecules

The B3LYP/6-31G(df,3p) model for the calculation of deuterium nuclear quadrupole coupling constants (nqcc's) is shown to yield results as accurate as calculations previously performed at the MP4 level of theory. For 25 molecules, ranging from HD and DF to pyridine and fluorobenzene, the rms difference between the B3LYP nqcc's and the experimental nqcc's is 3.2 kHz (2.7%). For benzene, our calculations suggest that the experimental χ_bband χ_ccof S. Jans-Bürli, M. Oldani, and A. Bauder, 1989.Mol. Phys.,68, 1111–1123) have been incorrectly assigned with respect to inertia axes and should be reversed. For borane carbonyl and nitric acid, it is shown that nqcc calculations using hydrogen bond lengths given by MP2/6-311 + G(d,p) optimizations in combination with the heavy atom experimental structures significantly improve agreement with the experimental nqcc's.     

Microwave Spectrum,Nuclear Quadrupole Coupling Constants,and Structure of Bromodifluoromethane

The microwave spectrum of bromodifluoromethane, CHBrF₂(Halon 1201) has been studied for the first time from 7 to 40 GHz. A least-squares analysis of the observedc-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows:A= 10199.7186(62) MHz,B= 2903.4150(26) MHz,C= 2360.1521(23) MHz, Δ_J= 0.660(14) kHz, Δ_JK= 2.87(11) kHz, Δ_K= 8.95 kHz, δ_J= 0.1344(24) kHz, δ_K= 3.22(15) kHz, χ_aa= 521.281(92) MHz, χ_bb− χ_cc= −38.32(9) MHz, and |χ_ac| = 187.1(26) MHz for the⁷⁹Br species;A= 10199.5567(54) MHz,B= 2876.5588(20) MHz,C= 2342.3796(18) MHz, Δ_J= 0.652(12) kHz, Δ_JK= 2.77(9) kHz, Δ_K= 8.21(61) kHz, δ_J= 0.1300(19) kHz, δ_K= 2.97(13) kHz, χ_aa= 435.61(10) MHz, χ_bb− χ_cc= −32.08(8) MHz, and |χ_ac| = 148.5(29) MHz for the⁸¹Br species. The structural parameters are calculated from all these rotational constants and the electronic properties of the carbon–bromine bond in bromodifluoromethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules.     

Intramolecular Force Fields and Vibrational Amplitudes of Disulfur Monoxide Isotopes

The force constants of S₂O have been calculated smploying GVFF and UBFF models. The reliability of the set of force constants have been examined. The mean amplitudes of vibration have also been evaluated at three temperatures, viz., 0°K, 298·15°K and 500°K. The results have been briefly discussed. The mean amplitude values will be helpful in interpretation of the electron diffraction data whenever available.     

Studies of the hyperfine interaction of111Cd in gaseous InCl and InCl3 systems

Using the perturbed γ-γ angular correlation at excited¹¹¹Cd-ions from the decay of¹¹¹In, the time-integral attenuation coefficientG ₂₂(∞) was measured in gaseous InCl and InCl₃ surroundings. The perturbation depends as well on the character and the density of the surrounding gas, as on the angular momentum of the electronic shell of the Cd-ion.G ₂₂(∞) varied between 0.012 and 0.828, while the molecule densities varied between 2×10¹⁴ and 2×10²⁰ molecules/cm³. For high densities it is to be noted, that the perturbation vanishes much faster for the InCl systems. Using a stochastic model, it is possible to calculate the mean hyperfine frequency Ω₀, and to estimate cross-sections for molecule-ion collisions at thermal energies.