Transition probabilities of forbidden lines in Pb I

Multiconfiguration Dirac-Fock as well as semiempirical calculations of decay rates of forbidden transitions within the ground 6s ² 6p ² configuration of neutral lead are reported and compared with relativistic Hartree-Fock results as well as with available experimental data. Received: 15 July 1998 / Received in final form: 15 October 1998     

Calculation of Electric Mult ipole Moment Integrals Using Translation Formulas for Slater-Type Orbitals

Using translation formulas for Slater-type orbitals the infinite series through the overlap integrals are derived for the electric multipole moment integrals. By the use of the derived expressions the electric multipole moment integrals, and therefore, the electric properties of molecules can be evaluated most efficiently and accurately. The convergence of the series is tested by calculating concrete cases. An accuracy of for 10^-5 the computer results is obtained for 1 ≤ v ≤ 5, and for the arbitrary values of internuclear distances and screening constants of atomic orbitals.     

Approximate formulae for the overlap integral of two harmonic oscillator wave functions

The use of second-order perturbation theory to derive approximate formulae for the overlap integral of two harmonic oscillator wave functions is discussed, and the results applied to the theory of intensity distributions in vibrational progressions in electronic spectra. For the vibrational progression m←0 an approximate formula is given which, when the vibrational frequencies of the initial and final states differ by less than 10%, reproduces to an accuracy of 1% or less the intensity profile calculated using the exact formulae for the overlap integrals.     

Fragmentation cross-section of relativistic oxygen ions and determination of overlap parameter

Fragmentation cross-section of¹⁶O relativistic ions, at two different energies, was measured in CsI crystal. An experiment designed basically to study primary cosmic ray nuclei, was exposed to monoenergetic beam of¹⁶O ions of bevatron. Fragmentation of the ions was observed in a two layer CsI target. Each CsI crystal was 1 inch thick. The main energy of the beam was 2.1 GeV/nucleon. A subsidiary beam of 0.5 GeV/nucleon oxygen-ions was created for this experiment alone. The number of fragmentations occurring in each crystal was used to obtain the total fragmentation cross-section at these energies. The Bradt-Peters overlap parameter was derived from these cross-sections. The experiment was designed and fabricated at the Department of Physics and Astronomy, Louisiana State University, Baton Rouge, USA and was performed in the accelerator facilities of the University of California, Berkeley, Calif., USA.     

Evaluation of Incomplete Gamma Functions Using Downward Recursion and Analytical Relations

New downward recursion and analytical approaches are presented for the calculation of incomplete gamma functions (,x) and (,x). The efficiency of calculation with an adequate interval of these expressions is compared with those of other methods and great numerical stability and good rate of convergence is obtained for wide range of integral parameters. It is shown that the downward recursive relations are stable for all values of and x of (,x).     

Approach to hydrodynamic equilibrium and its time dependence in the system EHEC/SDS/Water

The properties of the system EHEC/SDS/water in solution show considerable time dependence during several hours after preparation. The paper discusses various reasons for this time dependence. Similar time dependence in polymer solutions has been observed elsewhere. It is found that although the system properties vary, a true equilibrium is finally attained for all compositions. The most pronounced time dependence is shown in a region close to and above the CMC of a pure surfactant solution and for polymer concentrations at least equal to the critical overlap concentration. It is proposed that part of the explanation resides in the fact that in the solution preparation there appears intermediate states corresponding to high local polymer concentrations. Some quantitative aspects of the time dependence are also discussed.     

Maximum Overlap Symmetry Molecular Orbital Calculation under CNDO／2 Approximation

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角度重叠模型的应用 Ⅰ.计算过渡金属配合物电子光谱的微机程序

按照角度重叠模型,用FORTRAN语言编写了计算过渡金属配合物电子光谱的微机程序。     

Evaluation of Two-center One- and Two-electron Integrals over Slater Type Orbitals

A formulation previously presented by the authors for coulomb integrals was generalized to other two-center integrals, except exchange integral. Within this frame, molecular integrals were expressed in terms of some new functions closely related to the well-known incomplete gamma functions and these functions recursively evaluated. Special issues arising in the case of hybrid integrals were addressed, and the results were compared with the ones found in the literature.