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81.
N. C. Handy 《Theoretical chemistry accounts》1973,31(3):201-204
Boys and Handy [1] have discussed the solution of the bivariational equations with restricted numerical integration. One of the weaknesses of the method was that in the numerical summations over points, some points arose with r
ij= 0 and non-zero weights. This makes the method quite impractical for the Schrodinger Hamiltonian (because of the singularity at r
ij= 0), and it cannot be advantageous for the transcorrelated Hamiltonian C–1HC because there will be some discontinuous higher derivatives at r
ij=0. Here it is shown how the symmetry of cylindrically symmetric molecules can be used to eliminate such points, without losing any of the advantages of the overall method, such as the convergence of the eigensolutions. It is also shown how the primary numerical integration points (z
i, ri) may be chosen in any calculation such that each is associated with an equal amount of one-electron density. The choice of the angular coordinates are governed by the removal of the r
ij=0 points and maintaining the natural orthogonality between orbitals of different symmetry types. The method has been programmed and found to be practical, although no new molecular calculations have yet been performed. It is to be hoped that these points will give a basis for new transcorrelated calculations on diatomic molecules.This paper was presented during the session on numerical integration methods for molecules of the 1970 Quantum Theory Conference in Nottingham. It has been revised in the light of the interesting discussion which followed. 相似文献
82.
A bound is given for the average length of a lexicographic path, a definition that is motivated by degeneracies encountered when using the randomized simplex method. 相似文献
83.
The spherical-model limitn of then-vector model in a random field, with either a statistically independent distribution or with long-range correlated random fields, is studied to demonstrate the correctness of the replica method in which then and replica limits limits are interchanged, provided the replica and thermodynamic limits are taken in the right order, in the case of long-range correlated random fields. A scaling form for the two-point correlation function relevant to the first-order phase transition below the lower critical dimensionality of the random system is also obtained. 相似文献
84.
85.
Gary W. Schnuelle S. Swaminathan David L. Beveridge 《Theoretical chemistry accounts》1978,48(1):17-27
A theoretical study of ion hydration using the statistical thermodynamic supermolecule-continuum method is described. The cell and shell methods are used for configurational averaging. Enthalpies, free energies and entropies are calculated for Li+, Na+, K+, F– and Cl– each four coordinated with water. The results are in reasonable accord with experiment. A comparison of the site method, cell method and shell method results is presented. The supermolecule-continuum approach to solvent effects seems to be capable of accommodating essential features for the calculation of solvation energy and solvent effects on structure and properties. 相似文献
86.
Turevskaya E.P. Berdyev D.V. Turova N.Ya. 《Journal of Sol-Gel Science and Technology》1997,8(1-3):111-115
Complex formation in solutions of barium and zirconium alkoxides in ROH (R=i-Pr, Et) was studied. A number of bimetallic complexes were isolated, and their structure and properties were studied. The
sol-gel method yields a single-phase BaZrO3 powder only wheni-PrOH solutions of the alkoxides are used. In this case, the oxocomplex, BaZrO(OPr-i)4.(1–2)i-PrOH, is the precursor of the mixed oxide. 相似文献
87.
A.A. FilaretovM.G. Zhizhin L.N. KomissarovaV.P. Danilov V.V. ChernyshevB.I. Lazoryak 《Journal of solid state chemistry》2002,166(2):362-368
A new ammonium indium phosphate (NH4)In(OH)PO4 was prepared by hydrothermal reaction in the In2O3-NH4H2PO4-NH3/OH system (T=200°C, autogenous pressure, 7 days). The formula (NH4)In(OH)PO4 was determined on the basis of chemical and thermal analysis (TG/DSC), X-ray powder diffraction and IR-spectroscopy. (NH4)In(OH)PO4 crystallizes in the tetragonal system with space group P43212 (No. 96); a=9.4232(1) Å, c=11.1766(1) Å, V=992.45(2) Å3; Z=8. The crystal structure was refined by the Rietveld method (Rw=6.35%, Rp=5.10%). The second-harmonic generation study confirmed that structure of (NH4)In(OH)PO4 does not have a center of symmetry. The cis-InO4(OH)2 octahedra form helical chains, parallel to the c-axis. The In-O-In bonds are nearly equidistant. The chains are interconnected by phosphate tetrahedra and create tunnels containing the NH4+ ions along the c-axis. (NH4)In(OH)PO4 is isostructural with RbIn(OH)PO4. 相似文献
88.
A master equation is used to study transitions between the stable limit cycle and stable focus in the two-variable bistable system. The distribution function of the mean first passage time between these attractors and the relative dispersion of the mean first return time from the stable focus to itself as a function of the intensity of fluctuations are calculated and discussed. A coherence resonance is observed for the return time from the focus to itself. 相似文献
89.
计算机专用实时母系统在VAX/VMS环境下的实现 总被引:3,自引:1,他引:2
“母系统—子系统”的工作方式是计算机专用实时系统研制中的一次重要尝试,本文闸明计算机专用实时母系统在VAX/VMS环境下的工程实现。 相似文献
90.