International Nuclear Information System (INIS)
Brut, F.
1982-01-01
The spectroscopy of odd-A nuclei, in the 1p and 2s-1d shells, is studied in the framework of the projected Hartree-Fock method and by the generator coordinate method. The nuclear effective interactions of Cohen and Kurath, on the one hand, and of Kuo or Preedom-Wildenthal, on the other hand, are used. The binding energies, the nuclear spectra, the static moments and the electromagnetic transitions obtained by these two approaches are compared to the same quantities given by a complete diagonalization in the shell model basis. This study of light nuclei gives some possibilities to put in order the energy levels by coupled rotational bands. In the microscopic approach, thus we find all the elements of the unified model of Bohr and Mottelson. To give evidence of such a relation, the functions of the angle β, in the integrals of the projection method of Peierls and Yoccoz, for a Slater determinant, are developed in the vicinity of the bounds β = O and β = π. The microscopic coefficients are evaluated in the Hartree-Fock approximation, using the particle-hole formalism. Calculations are made for 20 Ne and 21 Ne and the resulting microscopic coefficients are compared with the corresponding terms of the unified model of Bohr and Mottelson [fr
Toroidal Superheavy Nuclei in Skyrme-Hartree-Fock Approach
International Nuclear Information System (INIS)
Staszczak, A.; Wong, Cheuk-Yin
2009-01-01
Within the self-consistent constraint Skyrme-Hartree-Fock+BCS model (SHF+BCS), we found equilibrium toroidal nuclear density distributions in the region of superheavy elements. For nuclei with a sufficient oblate deformation (Q 20 < -200 b), it becomes energetically favorable to change the genus of nuclear surface from 0 to 1, i.e., to switch the shape from a biconcave disc to a torus. The energy of the toroidal (genus=1) SHF+BCS solution relative to the compact (genus=0) ground state energy is strongly dependent both on the atomic number Z and the mass number A. We discuss the region of Z and A where the toroidal SHF+BCS total energy begins to be a global minimum
Linearized Jastrow-style fluctuations on spin-projected Hartree-Fock
International Nuclear Information System (INIS)
Henderson, Thomas M.; Scuseria, Gustavo E.
2013-01-01
The accurate and efficient description of strong electronic correlations remains an important objective in electronic structure theory. Projected Hartree-Fock theory, where symmetries of the Hamiltonian are deliberately broken and projectively restored, all with a mean-field computational scaling, shows considerable promise in this regard. However, the method is neither size extensive nor size consistent; in other words, the correlation energy per particle beyond broken-symmetry mean field vanishes in the thermodynamic limit, and the dissociation limit of a molecule is not the sum of the fragment energies. These two problems are closely related. Recently, Neuscamman [Phys. Rev. Lett. 109, 203001 (2012)] has proposed a method to cure the lack of size consistency in the context of the antisymmetrized geminal power wave function (equivalent to number-projected Hartree-Fock-Bogoliubov) by using a Jastrow-type correlator in Hilbert space. Here, we apply the basic idea in the context of projected Hartree-Fock theory, linearizing the correlator for computational simplicity but extending it to include spin fluctuations. Results are presented for the Hubbard Hamiltonian and for some simple molecular systems
International Nuclear Information System (INIS)
Loebl, N.; Maruhn, J. A.; Reinhard, P.-G.
2011-01-01
By calculating the Wigner distribution function in the reaction plane, we are able to probe the phase-space behavior in the time-dependent Hartree-Fock scheme during a heavy-ion collision in a consistent framework. Various expectation values of operators are calculated by evaluating the corresponding integrals over the Wigner function. In this approach, it is straightforward to define and analyze quantities even locally. We compare the Wigner distribution function with the smoothed Husimi distribution function. Different reaction scenarios are presented by analyzing central and noncentral 16 O + 16 O and 96 Zr + 132 Sn collisions. Although we observe strong dissipation in the time evolution of global observables, there is no evidence for complete equilibration in the local analysis of the Wigner function. Because the initial phase-space volumes of the fragments barely merge and mean values of the observables are conserved in fusion reactions over thousands of fm/c, we conclude that the time-dependent Hartree-Fock method provides a good description of the early stage of a heavy-ion collision but does not provide a mechanism to change the phase-space structure in a dramatic way necessary to obtain complete equilibration.
Angular momentum projection on a mesh of cranked Hartree-Fock wave functions
International Nuclear Information System (INIS)
Baye, D.; Heenen, P.
1984-01-01
A method for projecting on angular momentum wave functions discretized on a three-dimensional Cartesian mesh is presented. The method is based on a matrix representation of the rotation operator. It is applied to cranked Hartree-Fock wave functions calculated for 24 Mg with a simple interaction. In this case, the accuracy of the projected matrix elements is estimated to be of the order of 0.1%. An extensive comparison of the projected and cranking energies is made. The validity of the cranking method as an approximation to a variation-after-projection calculation seems to be wider than usually expected. The study of the fission barrier of 24 Mg for the channel 4 He- 16 O- 4 He shows that the cranking predictions for these very deformed states are quite reliable
On the relation between the Hartree-Fock and Kohn-Sham approaches
Energy Technology Data Exchange (ETDEWEB)
Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, 91904 Jerusalem (Israel); A.F. Ioffe Physical-Technical Institute, 194021 St. Petersburg (Russian Federation); Msezane, A.Z. [CTSPS, Clark Atlanta University, Atlanta, GA 30314 (United States); Shaginyan, V.R. [CTSPS, Clark Atlanta University, Atlanta, GA 30314 (United States); Petersburg Nuclear Physics Institute, 188300 Gatchina (Russian Federation)]. E-mail: vrshag@thd.pnpi.spb.ru; Sokolovski, D. [Queen' s University of Belfast, Belfast BT7 1NN (United Kingdom)
2004-09-13
We show that the Hartree-Fock (HF) results cannot be reproduced within the framework of Kohn-Sham (KS) theory because the single-particle densities of finite systems obtained within the HF calculations are not v-representable, i.e., do not correspond to any ground state of a N non-interacting electron systems in a local external potential. For this reason, the KS theory, which finds a minimum on a different subset of all densities, can overestimate the ground state energy, as compared to the HF result. The discrepancy between the two approaches provides no grounds to assume that either the KS theory or the density functional theory suffers from internal contradictions.
On the relation between the Hartree-Fock and Kohn-Sham approaches
International Nuclear Information System (INIS)
Amusia, M.Ya.; Msezane, A.Z.; Shaginyan, V.R.; Sokolovski, D.
2004-01-01
We show that the Hartree-Fock (HF) results cannot be reproduced within the framework of Kohn-Sham (KS) theory because the single-particle densities of finite systems obtained within the HF calculations are not v-representable, i.e., do not correspond to any ground state of a N non-interacting electron systems in a local external potential. For this reason, the KS theory, which finds a minimum on a different subset of all densities, can overestimate the ground state energy, as compared to the HF result. The discrepancy between the two approaches provides no grounds to assume that either the KS theory or the density functional theory suffers from internal contradictions
Projection after variation in the finite-temperature Hartree-Fock-Bogoliubov approximation
Fanto, P.
2017-11-01
The finite-temperature Hartree-Fock-Bogoliubov (HFB) approximation often breaks symmetries of the underlying many-body Hamiltonian. Restricting the calculation of the HFB partition function to a subspace with good quantum numbers through projection after variation restores some of the correlations lost in breaking these symmetries, although effects of the broken symmetries such as sharp kinks at phase transitions remain. However, the most general projection after variation formula in the finite-temperature HFB approximation is limited by a sign ambiguity. Here, I extend the Pfaffian formula for the many-body traces of HFB density operators introduced by Robledo [L. M. Robledo, Phys. Rev. C. 79, 021302(R) (2009), 10.1103/PhysRevC.79.021302] to eliminate this sign ambiguity and evaluate the more complicated many-body traces required in projection after variation in the most general HFB case. The method is validated through a proof-of-principle calculation of the particle-number-projected HFB thermal energy in a simple model.
Quantum treatment of protons with the reduced explicitly correlated Hartree-Fock approach
Energy Technology Data Exchange (ETDEWEB)
Sirjoosingh, Andrew; Pak, Michael V.; Brorsen, Kurt R.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Ave., Urbana, Illinois 61801 (United States)
2015-06-07
The nuclear-electronic orbital (NEO) approach treats select nuclei quantum mechanically on the same level as the electrons and includes nonadiabatic effects between the electrons and the quantum nuclei. The practical implementation of this approach is challenging due to the significance of electron-nucleus dynamical correlation. Herein, we present a general extension of the previously developed reduced NEO explicitly correlated Hartree-Fock (RXCHF) approach, in which only select electronic orbitals are explicitly correlated to each quantum nuclear orbital via Gaussian-type geminal functions. Approximations of the electronic exchange between the geminal-coupled electronic orbitals and the other electronic orbitals are also explored. This general approach enables computationally tractable yet accurate calculations on molecular systems with quantum protons. The RXCHF method is applied to the hydrogen cyanide (HCN) and FHF{sup −} systems, where the proton and all electrons are treated quantum mechanically. For the HCN system, only the two electronic orbitals associated with the CH covalent bond are geminal-coupled to the proton orbital. For the FHF{sup −} system, only the four electronic orbitals associated with the two FH covalent bonds are geminal-coupled to the proton orbital. For both systems, the RXCHF method produces qualitatively accurate nuclear densities, in contrast to mean field-based NEO approaches. The development and implementation of the RXCHF method provide the framework to perform calculations on systems such as proton-coupled electron transfer reactions, where electron-proton nonadiabatic effects are important.
Spin Hartree-Fock approach to studying quantum Heisenberg antiferromagnets in low dimensions
Werth, A.; Kopietz, P.; Tsyplyatyev, O.
2018-05-01
We construct a new mean-field theory for a quantum (spin-1/2) Heisenberg antiferromagnet in one (1D) and two (2D) dimensions using a Hartree-Fock decoupling of the four-point correlation functions. We show that the solution to the self-consistency equations based on two-point correlation functions does not produce any unphysical finite-temperature phase transition, in accord with the Mermin-Wagner theorem, unlike the common approach based on the mean-field equation for the order parameter. The next-neighbor spin-spin correlation functions, calculated within this approach, reproduce closely the strong renormalization by quantum fluctuations obtained via a Bethe ansatz in 1D and a small renormalization of the classical antiferromagnetic state in 2D. The heat capacity approximates with reasonable accuracy the full Bethe ansatz result at all temperatures in 1D. In 2D, we obtain a reduction of the peak height in the heat capacity at a finite temperature that is accessible by high-order 1 /T expansions.
The Hartree-Fock seniority approximation
International Nuclear Information System (INIS)
Gomez, J.M.G.; Prieto, C.
1986-01-01
A new self-consistent method is used to take into account the mean-field and the pairing correlations in nuclei at the same time. We call it the Hartree-Fock seniority approximation, because the long-range and short-range correlations are treated in the frameworks of Hartree-Fock theory and the seniority scheme. The method is developed in detail for a minimum-seniority variational wave function in the coordinate representation for an effective interaction of the Skyrme type. An advantage of the present approach over the Hartree-Fock-Bogoliubov theory is the exact conservation of angular momentum and particle number. Furthermore, the computational effort required in the Hartree-Fock seniority approximation is similar to that ofthe pure Hartree-Fock picture. Some numerical calculations for Ca isotopes are presented. (orig.)
Generalized Hartree-Fock-Bogoliubov approach in the description of many-body systems
International Nuclear Information System (INIS)
Janssen, D.
1979-01-01
The quantum mechanical equation for a group of states connected by large probabilities of transitions to each other, i.e. possessing common internal structure, is found. No phenomenological assumptions about the vibrational or rotational character of these states have been used. The equations obtained here can be understood as a direct generalization of the Hartree-Fock-Bogoliubov equation, this scheme including not only the ground state, but some excited states as well. The question of normalization of the density matrix in the generalized space has been solved and the additional solutions of the problem have been excluded. (author)
Time-dependent Hartree-Fock approach to nuclear ``pasta'' at finite temperature
Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Maruhn, J. A.; Mecke, K.; Reinhard, P.-G.
2013-05-01
We present simulations of neutron-rich matter at subnuclear densities, like supernova matter, with the time-dependent Hartree-Fock approximation at temperatures of several MeV. The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. This matter evolves into spherical, rod-like, and slab-like shapes and mixtures thereof. The simulations employ a full Skyrme interaction in a periodic three-dimensional grid. By an improved morphological analysis based on Minkowski functionals, all eight pasta shapes can be uniquely identified by the sign of only two valuations, namely the Euler characteristic and the integral mean curvature. In addition, we propose the variance in the cell density distribution as a measure to distinguish pasta matter from uniform matter.
Time-Dependent Hartree-Fock Approach to Nuclear Pasta at Finite Temperature
International Nuclear Information System (INIS)
Schuetrumpf, B; Maruhn, J A; Klatt, M A; Mecke, K; Reinhard, P-G; Iida, K
2013-01-01
We present simulations of neutron-rich matter at subnuclear densities, like supernova matter, with the time-dependent Hartree-Fock approximation at temperatures of several MeV. The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. This matter evolves into spherical, rod-like, and slab-like shapes and mixtures thereof. The simulations employ a full Skyrme interaction in a periodic three-dimensional grid. By an improved morphological analysis based on Minkowski functionals, all eight pasta shapes can be uniquely identified by the sign of only two valuations, namely the Euler characteristic and the integral mean curvature.
Time-Dependent Hartree-Fock Approach to Nuclear Pasta at Finite Temperature
Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Maruhn, J. A.; Mecke, K.; Reinhard, P.-G.
2013-03-01
We present simulations of neutron-rich matter at subnuclear densities, like supernova matter, with the time-dependent Hartree-Fock approximation at temperatures of several MeV. The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. This matter evolves into spherical, rod-like, and slab-like shapes and mixtures thereof. The simulations employ a full Skyrme interaction in a periodic three-dimensional grid. By an improved morphological analysis based on Minkowski functionals, all eight pasta shapes can be uniquely identified by the sign of only two valuations, namely the Euler characteristic and the integral mean curvature.
Hartree-Fock+BCS approach to unstable nuclei with the Skyrme force
International Nuclear Information System (INIS)
Tajima, Naoki
2001-01-01
We reanalyze the results of our extensive Hartree-Fock+BCS calculation from new points of view paying attention to the properties of unstable nuclei. The calculation has been done with the Skyrme SIII force for the ground and shape isomeric states of 1029 even-even nuclei ranging 2≤Z≤114. We also discuss the advantages of the employed three-dimensional Cartesian-mesh representation, especially on its remarkably high precision with apparently coarse meshes when applied to atomic nuclei. In Appendices we give the coefficients of finite-point numerical differentiation and integration formulae suitable for Cartesian mesh representation and elucidate the features of each formula and the differences from a method based on the Fourier transformation. (author)
Energy Technology Data Exchange (ETDEWEB)
Garza, Alejandro J.; Jiménez-Hoyos, Carlos A. [Department of Chemistry, Rice University, Houston, Texas 77251-1892 (United States); Scuseria, Gustavo E. [Department of Chemistry and Department of Physics and Astronomy, Rice University, Houston, Texas 77251-1892, USA and Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)
2014-06-28
Several schemes to avoid the double counting of correlations in methods that merge multireference wavefunctions with density functional theory (DFT) are studied and here adapted to a combination of spin-projected Hartree-Fock (SUHF) and DFT. The advantages and limitations of the new method, denoted SUHF+f{sub c}DFT, are explored through calculations on benchmark sets in which the accounting of correlations is challenging for pure SUHF or DFT. It is shown that SUHF+f{sub c}DFT can greatly improve the description of certain molecular properties (e.g., singlet-triplet energy gaps) which are not improved by simple addition of DFT dynamical correlation to SUHF. However, SUHF+f{sub c}DFT is also shown to have difficulties dissociating certain types of bonds and describing highly charged ions with static correlation. Possible improvements to the current SUHF+f{sub c}DFT scheme are discussed in light of these results.
International Nuclear Information System (INIS)
Smeyers, Y.G.; Delgado-Barrio, G.
1976-01-01
The half-projected Hartree--Fock function for singlet states (HPHF) is analyzed in terms of natural electronic configurations. For this purpose the HPHF spinless density matrix and its natural orbitals are first deduced. It is found that the HPHF function does not contain any contribution from odd-times excited configurations. It is seen in addition, in the case of the singlet ground states, this function is approximately equivalent to two closed-shell configurations, although the nature of the excited one depends on the nuclear geometry. An example is given in the case of the LiH ground state. Finally, the application of this model for studying systems of more than two atoms is criticized
International Nuclear Information System (INIS)
Lorenzana, J.; Grynberg, M.D.; Yu, L.; Yonemitsu, K.; Bishop, A.R.
1992-11-01
The ground state energy, and static and dynamic correlation functions are investigated in the inhomogeneous Hartree-Fock (HF) plus random phase approximation (RPA) approach applied to a one-dimensional spinless fermion model showing self-trapped doping states at the mean field level. Results are compared with homogeneous HF and exact diagonalization. RPA fluctuations added to the generally inhomogeneous HF ground state allows the computation of dynamical correlation functions that compare well with exact diagonalization results. The RPA correction to the ground state energy agrees well with the exact results at strong and weak coupling limits. We also compare it with a related quasi-boson approach. The instability towards self-trapped behaviour is signaled by a RPA mode with frequency approaching zero. (author). 21 refs, 10 figs
Nuclear Pasta at Finite Temperature with the Time-Dependent Hartree-Fock Approach
International Nuclear Information System (INIS)
Schuetrumpf, B; Maruhn, J A; Klatt, M A; Mecke, K; Reinhard, P-G; Iida, K
2016-01-01
We present simulations of neutron-rich matter at sub-nuclear densities, like supernova matter. With the time-dependent Hartree-Fock approximation we can study the evolution of the system at temperatures of several MeV employing a full Skyrme interaction in a periodic three-dimensional grid [1].The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter.The matter evolves into spherical, rod-like, connected rod-like and slab-like shapes. Further we observe gyroid-like structures, discussed e.g. in [2], which are formed spontaneously choosing a certain value of the simulation box length. The ρ-T-map of pasta shapes is basically consistent with the phase diagrams obtained from QMD calculations [3]. By an improved topological analysis based on Minkowski functionals [4], all observed pasta shapes can be uniquely identified by only two valuations, namely the Euler characteristic and the integral mean curvature.In addition we propose the variance in the cell-density distribution as a measure to distinguish pasta matter from uniform matter. (paper)
Nuclear Pasta at Finite Temperature with the Time-Dependent Hartree-Fock Approach
Schuetrumpf, B.; Klatt, M. A.; Iida, K.; Maruhn, J. A.; Mecke, K.; Reinhard, P.-G.
2016-01-01
We present simulations of neutron-rich matter at sub-nuclear densities, like supernova matter. With the time-dependent Hartree-Fock approximation we can study the evolution of the system at temperatures of several MeV employing a full Skyrme interaction in a periodic three-dimensional grid [1]. The initial state consists of α particles randomly distributed in space that have a Maxwell-Boltzmann distribution in momentum space. Adding a neutron background initialized with Fermi distributed plane waves the calculations reflect a reasonable approximation of astrophysical matter. The matter evolves into spherical, rod-like, connected rod-like and slab-like shapes. Further we observe gyroid-like structures, discussed e.g. in [2], which are formed spontaneously choosing a certain value of the simulation box length. The ρ-T-map of pasta shapes is basically consistent with the phase diagrams obtained from QMD calculations [3]. By an improved topological analysis based on Minkowski functionals [4], all observed pasta shapes can be uniquely identified by only two valuations, namely the Euler characteristic and the integral mean curvature. In addition we propose the variance in the cell-density distribution as a measure to distinguish pasta matter from uniform matter.
International Nuclear Information System (INIS)
Sugimoto, Satoru; Ikeda, Kiyomi; Toki, Hiroshi
2004-01-01
We propose a new mean-field-type framework which can treat the strong correlation induced by the tensor force. To treat the tensor correlation we break the charge and parity symmetries of a single-particle state and restore these symmetries of the total system by the projection method. We perform the charge and parity projections before variation and obtain a Hartree-Fock-like equation, which is solved self-consistently. We apply the Hartree-Fock-like equation to the alpha particle and find that by breaking the parity and charge symmetries, the correlation induced by the tensor force is obtained in the projected mean-field framework. We emphasize that the projection before the variation is important to pick up the tensor correlation in the present framework
International Nuclear Information System (INIS)
Brorsen, Kurt R.; Sirjoosingh, Andrew; Pak, Michael V.; Hammes-Schiffer, Sharon
2015-01-01
The nuclear electronic orbital (NEO) reduced explicitly correlated Hartree-Fock (RXCHF) approach couples select electronic orbitals to the nuclear orbital via Gaussian-type geminal functions. This approach is extended to enable the use of a restricted basis set for the explicitly correlated electronic orbitals and an open-shell treatment for the other electronic orbitals. The working equations are derived and the implementation is discussed for both extensions. The RXCHF method with a restricted basis set is applied to HCN and FHF − and is shown to agree quantitatively with results from RXCHF calculations with a full basis set. The number of many-particle integrals that must be calculated for these two molecules is reduced by over an order of magnitude with essentially no loss in accuracy, and the reduction factor will increase substantially for larger systems. Typically, the computational cost of RXCHF calculations with restricted basis sets will scale in terms of the number of basis functions centered on the quantum nucleus and the covalently bonded neighbor(s). In addition, the RXCHF method with an odd number of electrons that are not explicitly correlated to the nuclear orbital is implemented using a restricted open-shell formalism for these electrons. This method is applied to HCN + , and the nuclear densities are in qualitative agreement with grid-based calculations. Future work will focus on the significance of nonadiabatic effects in molecular systems and the further enhancement of the NEO-RXCHF approach to accurately describe such effects
Energy Technology Data Exchange (ETDEWEB)
Brorsen, Kurt R.; Sirjoosingh, Andrew; Pak, Michael V.; Hammes-Schiffer, Sharon, E-mail: shs3@illinois.edu [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Ave., Urbana, Illinois 61801 (United States)
2015-06-07
The nuclear electronic orbital (NEO) reduced explicitly correlated Hartree-Fock (RXCHF) approach couples select electronic orbitals to the nuclear orbital via Gaussian-type geminal functions. This approach is extended to enable the use of a restricted basis set for the explicitly correlated electronic orbitals and an open-shell treatment for the other electronic orbitals. The working equations are derived and the implementation is discussed for both extensions. The RXCHF method with a restricted basis set is applied to HCN and FHF{sup −} and is shown to agree quantitatively with results from RXCHF calculations with a full basis set. The number of many-particle integrals that must be calculated for these two molecules is reduced by over an order of magnitude with essentially no loss in accuracy, and the reduction factor will increase substantially for larger systems. Typically, the computational cost of RXCHF calculations with restricted basis sets will scale in terms of the number of basis functions centered on the quantum nucleus and the covalently bonded neighbor(s). In addition, the RXCHF method with an odd number of electrons that are not explicitly correlated to the nuclear orbital is implemented using a restricted open-shell formalism for these electrons. This method is applied to HCN{sup +}, and the nuclear densities are in qualitative agreement with grid-based calculations. Future work will focus on the significance of nonadiabatic effects in molecular systems and the further enhancement of the NEO-RXCHF approach to accurately describe such effects.
Spiral magnetism in the single-band Hubbard model: the Hartree-Fock and slave-boson approaches.
Igoshev, P A; Timirgazin, M A; Gilmutdinov, V F; Arzhnikov, A K; Irkhin, V Yu
2015-11-11
The ground-state magnetic phase diagram is investigated within the single-band Hubbard model for square and different cubic lattices. The results of employing the generalized non-correlated mean-field (Hartree-Fock) approximation and generalized slave-boson approach by Kotliar and Ruckenstein with correlation effects included are compared. We take into account commensurate ferromagnetic, antiferromagnetic, and incommensurate (spiral) magnetic phases, as well as phase separation into magnetic phases of different types, which was often lacking in previous investigations. It is found that the spiral states and especially ferromagnetism are generally strongly suppressed up to non-realistically large Hubbard U by the correlation effects if nesting is absent and van Hove singularities are well away from the paramagnetic phase Fermi level. The magnetic phase separation plays an important role in the formation of magnetic states, the corresponding phase regions being especially wide in the vicinity of half-filling. The details of non-collinear and collinear magnetic ordering for different cubic lattices are discussed.
Hartree-Fock-Bogolyubov Calculations
International Nuclear Information System (INIS)
Wolter, H.H.
1970-01-01
The author discusses in which way and to what extent pairing correlations affect the nuclear wave function. He finds that for many nuclei in the pf-shell the Hartree-Fock approximation is not valid. (author)
Hartree-Fock calculations of nuclear masses
International Nuclear Information System (INIS)
Quentin, P.
1976-01-01
Hartree-Fock calculations pertaining to the determination of nuclear binding energies throughout the whole chart of nuclides are reviewed. Such an approach is compared with other methods. Main techniques in use are shortly presented. Advantages and drawbacks of these calculations are also discussed with a special emphasis on the extrapolation towards nuclei far from the stability valley. Finally, a discussion of some selected results from light to superheavy nuclei, is given [fr
The Hartree-Fock approximation applied to nuclear structure problems
International Nuclear Information System (INIS)
Oliveira, D.R. de.
1972-01-01
The Hartree-Fock indepedent-particle state basis is firstly constructed, whose wave functions are expressed as linear combinations of states of a Known basis. The coefficients of these combinations are reals e from themselves the Hartree-Fock density matrix is defined. The symmetries which characterize the system in study are embedded in these coefficients and in the density matrix. The formalism is applied to the Ne 20 , Si 28 and Ar 36 nuclei whose lowest Hartree-Fock energies are obtained admitting that theirs wave functions having axial symmetry. Once known the Hartree-Fock wave function, states are projected from it with well-defined total angular momentum using the Peierls and Yoccoz method. From these wave functions energy levels of the ground band are calculated as well as the electric quadrupole transition probabilities among these levels. (L.C.) [pt
Semiclassical approximation to time-dependent Hartree--Fock theory
International Nuclear Information System (INIS)
Dworzecka, M.; Poggioli, R.
1976-01-01
Working within a time-dependent Hartree-Fock framework, one develops a semiclassical approximation appropriate for large systems. It is demonstrated that the standard semiclassical approach, the Thomas-Fermi approximation, is inconsistent with Hartree-Fock theory when the basic two-body interaction is short-ranged (as in nuclear systems, for example). However, by introducing a simple extension of the Thomas-Fermi approximation, one overcomes this problem. One also discusses the infinite nuclear matter problem and point out that time-dependent Hartree-Fock theory yields collective modes of the zero sound variety instead of ordinary hydrodynamic (first) sound. One thus emphasizes that one should be extremely circumspect when attempting to cast the equations of motion of time-dependent Hartree-Fock theory into a hydrodynamic-like form
Stability of the Hartree-Fock model with temperature
Dolbeault, Jean; Felmer, Patricio; Lewin, Mathieu
2008-01-01
This paper is devoted to the Hartree-Fock model with temperature in the euclidean space. For large classes of free energy functionals, minimizers are obtained as long as the total charge of the system does not exceed a threshold which depends on the temperature. The usual Hartree-Fock model is recovered in the zero temperature limit. An orbital stability result for the Cauchy problem is deduced from the variational approach.
SU(3) versus deformed Hartree-Fock state
International Nuclear Information System (INIS)
Johnson, Calvin W.; Stetcu, Ionel; Draayer, J.P.
2002-01-01
Deformation is fundamental to understanding nuclear structure. We compare two ways to efficiently realize deformation for many-fermion wave functions, the leading SU(3) irreducible representation and the angular-momentum-projected Hartree-Fock state. In the absence of single-particle spin-orbit splitting the two are nearly identical. With realistic forces, however, the difference between the two is nontrivial, with the angular-momentum-projected Hartree-Fock state better approximating an 'exact' wave function calculated in the fully interacting shell model. The difference is driven almost entirely by the single-particle spin-orbit splitting
International Nuclear Information System (INIS)
Sugimoto, Satoru; Toki, Hiroshi; Ikeda, Kiyomi
2008-01-01
We study the effect of the tensor force on nuclear structure with mean-field and beyond-mean-field methods. An important correlation induced by the tensor force is two-particle-two-hole (2p2h) correlation, which cannot be treated with a usual mean-filed method. To treat the 2p2h tensor correlation, we develop a new framework (charge- and parity-projected Hartree-Fock (CPPHF) method), which is a beyond-mean-field method. In the CPPHF method, we introduce single-particle states with parity and charge mixing. The parity and charge projections are performed on a total wave function before variation. We apply the CPPHF method to oxygen isotopes including neutron-rich ones. The potential energy from the tensor force has the same order of magnitude with that from the LS force and becomes smaller with neutron number, which indicates that excess neutrons do not contribute to the 2p2h tensor correlation significantly. We also study the effect of the tensor force on spin-orbit-splitting (ls-splitting) in a neutron-rich fluorine isotope 23 F. The tensor force reduces the ls-splitting for the proton d-orbits by about 3 MeV. This effect is important to reproduce the experimental value. We also find that the 2p2h tensor correlation does not affect the ls-splitting in 23 F
International Nuclear Information System (INIS)
Lara-Castells, María Pilar de; Mitrushchenkov, Alexander O.; Stoll, Hermann
2015-01-01
A combined density functional (DFT) and incremental post-Hartree-Fock (post-HF) approach, proven earlier to calculate He-surface potential energy surfaces [de Lara-Castells et al., J. Chem. Phys. 141, 151102 (2014)], is applied to describe the van der Waals dominated Ag 2 /graphene interaction. It extends the dispersionless density functional theory developed by Pernal et al. [Phys. Rev. Lett. 103, 263201 (2009)] by including periodic boundary conditions while the dispersion is parametrized via the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)]. Starting with the elementary cluster unit of the target surface (benzene), continuing through the realistic cluster model (coronene), and ending with the periodic model of the extended system, modern ab initio methodologies for intermolecular interactions as well as state-of-the-art van der Waals-corrected density functional-based approaches are put together both to assess the accuracy of the composite scheme and to better characterize the Ag 2 /graphene interaction. The present work illustrates how the combination of DFT and post-HF perspectives may be efficient to design simple and reliable ab initio-based schemes in extended systems for surface science applications
Energy Technology Data Exchange (ETDEWEB)
Lara-Castells, María Pilar de, E-mail: Pilar.deLara.Castells@csic.es [Instituto de Física Fundamental (C.S.I.C.), Serrano 123, E-28006 Madrid (Spain); Mitrushchenkov, Alexander O. [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France); Stoll, Hermann [Institut für Theoretische Chemie, Universität Stuttgart, D-70550 Stuttgart (Germany)
2015-09-14
A combined density functional (DFT) and incremental post-Hartree-Fock (post-HF) approach, proven earlier to calculate He-surface potential energy surfaces [de Lara-Castells et al., J. Chem. Phys. 141, 151102 (2014)], is applied to describe the van der Waals dominated Ag{sub 2}/graphene interaction. It extends the dispersionless density functional theory developed by Pernal et al. [Phys. Rev. Lett. 103, 263201 (2009)] by including periodic boundary conditions while the dispersion is parametrized via the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)]. Starting with the elementary cluster unit of the target surface (benzene), continuing through the realistic cluster model (coronene), and ending with the periodic model of the extended system, modern ab initio methodologies for intermolecular interactions as well as state-of-the-art van der Waals-corrected density functional-based approaches are put together both to assess the accuracy of the composite scheme and to better characterize the Ag{sub 2}/graphene interaction. The present work illustrates how the combination of DFT and post-HF perspectives may be efficient to design simple and reliable ab initio-based schemes in extended systems for surface science applications.
International Nuclear Information System (INIS)
Schmid, K.W.; Gruemmer, F.
1979-01-01
A variational principle is used to determine the optimal angular momentum projected one determinant approach to the N-nucleon yrast-wave function for a given total spin value. The solution is given in terms of a set of coupled nonlinear equations. Besides an orthonormality constraint for the occupied orbits and a normalization conditions for the total wave function, this set consists out of a matrix equation taking care of the fact that the spin-projected wave function does not depend on the orientation of the intrinsic determinant it is based on, and a second subset of equations, which can be considered as a Thouless theorem for the spin-projected N-nucleon state, and desribes the diagonalization of the total Hamiltonian in the subspace of linear independent N-nucleon shell model configurations contained in the test-determinant. Furthermore, a numerical method for the solution of these equations is proposed and an extension of the theory for the description of excited bands is given. Finally, the consistency of the equations is checked by solving them for a simple example analytically. (orig.)
Hartree--Fock density matrix equation
International Nuclear Information System (INIS)
Cohen, L.; Frishberg, C.
1976-01-01
An equation for the Hartree--Fock density matrix is discussed and the possibility of solving this equation directly for the density matrix instead of solving the Hartree--Fock equation for orbitals is considered. Toward that end the density matrix is expanded in a finite basis to obtain the matrix representative equation. The closed shell case is considered. Two numerical schemes are developed and applied to a number of examples. One example is given where the standard orbital method does not converge while the method presented here does
Testing the multi-configuration time-dependent Hartree-Fock method
International Nuclear Information System (INIS)
Zanghellini, Juergen; Kitzler, Markus; Brabec, Thomas; Scrinzi, Armin
2004-01-01
We test the multi-configuration time-dependent Hartree-Fock method as a new approach towards the numerical calculation of dynamical processes in multi-electron systems using the harmonic quantum dot and one-dimensional helium in strong laser pulses as models. We find rapid convergence for quantities such as ground-state population, correlation coefficient and single ionization towards the exact results. The method converges, where the time-dependent Hartree-Fock method fails qualitatively
Hartree--Fock time-dependent problem
Energy Technology Data Exchange (ETDEWEB)
Bove, A; Fano, G [Bologna Univ. (Italy). Istituto di Fisica; Istituto Nazionale di Fisica Nucleare, Bologna (Italy)); Da Prato, G [Rome Univ. (Italy). Istituto di Matematica
1976-06-01
A previous result is generalized. An existence and uniqueness theorem is proved for the Hartree--Fock time-dependent problem in the case of a finite Fermi system interacting via a two body potential which is supposed to be dominated by the kinetic energy part of the one-particle Hamiltonian.
Energy Technology Data Exchange (ETDEWEB)
Ripka, G [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires
1968-09-01
Most of the content of this thesis is published in english in Advances In Nuclear Physics, Vol. 1 (Editors: Baranger and Vogt - Plenum Press). The Hartree- Fock equations are derived. The expansions of the orbits and the possible symmetries of the Hartree-Fock field are discussed. Wavefunctions of even-even N = Z nuclei are given for 12 {<=} A {<=} 40. The role of the monopole, quadrupole and exchange components of the force are discussed. The multiplicity of the solutions and the effect of the spin-orbit interaction are discussed. Exact angular momentum projection is used to generate rotational bands. The validity of the adiabatic rotational model in light nuclei is discussed. Hartree-Fock calculations are extended to include major-shell mixing in order to obtain quadrupole deformations without the use of effective charge. The incompressibility, of nuclei is discussed and the compatibility between the Hartree-Fock solutions, the Mottelson model of quadrupole deformations and the SU3 states of J.P. Elliott and M. Moshinsky is established. (author) [French] La theorie de Hartree-Fock est appliquee au calcul des fonctions d'onde des noyaux legers deformes. Les equations de Hartree-Fock, les symetries permises et le choix du developpement des orbites sont discutes. Les fonctions d'onde des noyaux pair-pairs N = Z (12 {<=} A {<=} 40) sont tabulees. Les contributions des composantes monopolaires et quadrupolaires ainsi que des termes d'echange de la force nucleon-nucleon sont discutees. La methode de projection de moment cinetique est utilisee pour engendrer les bandes de rotation. La validite du modele rotationnel adiabatique est discutee. Les calculs de Hartree-Fock qui tiennent compte du melange de plusieurs couches majeures dans chaque orbite sont appliques au calcul des deformations quadrupolaires sans l'utilisation de charge effective. L'incompressibilite des noyaux et la compatibilite des fonctions d'onde de Hartree- Fock avec les fonctions d'onde SU3 de J
Energy Technology Data Exchange (ETDEWEB)
Ripka, G. [Commissariat a l' Energie Atomique, 91 - Saclay (France). Centre d' Etudes Nucleaires
1968-09-01
Most of the content of this thesis is published in english in Advances In Nuclear Physics, Vol. 1 (Editors: Baranger and Vogt - Plenum Press). The Hartree- Fock equations are derived. The expansions of the orbits and the possible symmetries of the Hartree-Fock field are discussed. Wavefunctions of even-even N = Z nuclei are given for 12 {<=} A {<=} 40. The role of the monopole, quadrupole and exchange components of the force are discussed. The multiplicity of the solutions and the effect of the spin-orbit interaction are discussed. Exact angular momentum projection is used to generate rotational bands. The validity of the adiabatic rotational model in light nuclei is discussed. Hartree-Fock calculations are extended to include major-shell mixing in order to obtain quadrupole deformations without the use of effective charge. The incompressibility, of nuclei is discussed and the compatibility between the Hartree-Fock solutions, the Mottelson model of quadrupole deformations and the SU3 states of J.P. Elliott and M. Moshinsky is established. (author) [French] La theorie de Hartree-Fock est appliquee au calcul des fonctions d'onde des noyaux legers deformes. Les equations de Hartree-Fock, les symetries permises et le choix du developpement des orbites sont discutes. Les fonctions d'onde des noyaux pair-pairs N = Z (12 {<=} A {<=} 40) sont tabulees. Les contributions des composantes monopolaires et quadrupolaires ainsi que des termes d'echange de la force nucleon-nucleon sont discutees. La methode de projection de moment cinetique est utilisee pour engendrer les bandes de rotation. La validite du modele rotationnel adiabatique est discutee. Les calculs de Hartree-Fock qui tiennent compte du melange de plusieurs couches majeures dans chaque orbite sont appliques au calcul des deformations quadrupolaires sans l'utilisation de charge effective. L'incompressibilite des noyaux et la compatibilite des fonctions d'onde de Hartree- Fock avec les
Veeraraghavan, Srikant; Mazziotti, David A
2014-03-28
We present a density matrix approach for computing global solutions of restricted open-shell Hartree-Fock theory, based on semidefinite programming (SDP), that gives upper and lower bounds on the Hartree-Fock energy of quantum systems. While wave function approaches to Hartree-Fock theory yield an upper bound to the Hartree-Fock energy, we derive a semidefinite relaxation of Hartree-Fock theory that yields a rigorous lower bound on the Hartree-Fock energy. We also develop an upper-bound algorithm in which Hartree-Fock theory is cast as a SDP with a nonconvex constraint on the rank of the matrix variable. Equality of the upper- and lower-bound energies guarantees that the computed solution is the globally optimal solution of Hartree-Fock theory. The work extends a previously presented method for closed-shell systems [S. Veeraraghavan and D. A. Mazziotti, Phys. Rev. A 89, 010502-R (2014)]. For strongly correlated systems the SDP approach provides an alternative to the locally optimized Hartree-Fock energies and densities with a certificate of global optimality. Applications are made to the potential energy curves of C2, CN, Cr2, and NO2.
Generalized Hartree-Fock method for electron-atom scattering
International Nuclear Information System (INIS)
Rosenberg, L.
1997-01-01
In the widely used Hartree-Fock procedure for atomic structure calculations, trial functions in the form of linear combinations of Slater determinants are constructed and the Rayleigh-Ritz minimum principle is applied to determine the best in that class. A generalization of this approach, applicable to low-energy electron-atom scattering, is developed here. The method is based on a unique decomposition of the scattering wave function into open- and closed-channel components, so chosen that an approximation to the closed-channel component may be obtained by adopting it as a trial function in a minimum principle, whose rigor can be maintained even when the target wave functions are imprecisely known. Given a closed-channel trial function, the full scattering function may be determined from the solution of an effective one-body Schroedinger equation. Alternatively, in a generalized Hartree-Fock approach, the minimum principle leads to coupled integrodifferential equations to be satisfied by the basis functions appearing in a Slater-determinant representation of the closed-channel wave function; it also provides a procedure for optimizing the choice of nonlinear parameters in a variational determination of these basis functions. Inclusion of additional Slater determinants in the closed-channel trial function allows for systematic improvement of that function, as well as the calculated scattering parameters, with the possibility of spurious singularities avoided. Electron-electron correlations can be important in accounting for long-range forces and resonances. These correlation effects can be included explicitly by suitable choice of one component of the closed-channel wave function; the remaining component may then be determined by the generalized Hartree-Fock procedure. As a simple test, the method is applied to s-wave scattering of positrons by hydrogen. copyright 1997 The American Physical Society
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Rodriguez-Bautista, Mariano; Díaz-García, Cecilia; Navarrete-López, Alejandra M.; Vargas, Rubicelia; Garza, Jorge, E-mail: jgo@xanum.uam.mx [Departamento de Química, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Iztapalapa, San Rafael Atlixco 186, Col. Vicentina, Iztapalapa C. P. 09340, México D. F., México (Mexico)
2015-07-21
In this report, we use a new basis set for Hartree-Fock calculations related to many-electron atoms confined by soft walls. One- and two-electron integrals were programmed in a code based in parallel programming techniques. The results obtained with this proposal for hydrogen and helium atoms were contrasted with other proposals to study just one and two electron confined atoms, where we have reproduced or improved the results previously reported. Usually, an atom enclosed by hard walls has been used as a model to study confinement effects on orbital energies, the main conclusion reached by this model is that orbital energies always go up when the confinement radius is reduced. However, such an observation is not necessarily valid for atoms confined by penetrable walls. The main reason behind this result is that for atoms with large polarizability, like beryllium or potassium, external orbitals are delocalized when the confinement is imposed and consequently, the internal orbitals behave as if they were in an ionized atom. Naturally, the shell structure of these atoms is modified drastically when they are confined. The delocalization was an argument proposed for atoms confined by hard walls, but it was never verified. In this work, the confinement imposed by soft walls allows to analyze the delocalization concept in many-electron atoms.
Rodriguez-Bautista, Mariano; Díaz-García, Cecilia; Navarrete-López, Alejandra M; Vargas, Rubicelia; Garza, Jorge
2015-07-21
In this report, we use a new basis set for Hartree-Fock calculations related to many-electron atoms confined by soft walls. One- and two-electron integrals were programmed in a code based in parallel programming techniques. The results obtained with this proposal for hydrogen and helium atoms were contrasted with other proposals to study just one and two electron confined atoms, where we have reproduced or improved the results previously reported. Usually, an atom enclosed by hard walls has been used as a model to study confinement effects on orbital energies, the main conclusion reached by this model is that orbital energies always go up when the confinement radius is reduced. However, such an observation is not necessarily valid for atoms confined by penetrable walls. The main reason behind this result is that for atoms with large polarizability, like beryllium or potassium, external orbitals are delocalized when the confinement is imposed and consequently, the internal orbitals behave as if they were in an ionized atom. Naturally, the shell structure of these atoms is modified drastically when they are confined. The delocalization was an argument proposed for atoms confined by hard walls, but it was never verified. In this work, the confinement imposed by soft walls allows to analyze the delocalization concept in many-electron atoms.
New algorithm for Hartree-Fock variational equation
International Nuclear Information System (INIS)
Iwasawa, K.; Sakata, F.; Hashimoto, Y.; Terasaki, J.
1994-08-01
Aiming at microscopically understanding the shape-coexistence phenomena, a new algorithm for obtaining many self-consistent Hartree-Fock states is developed. In contrast with the conventional numerical method of solving the constrained Hartree-Fock equation which gives the most energetically favorable state under a given constrained condition, it can find many high-lying Hartree-Fock states as well as many continuous constraint Hartree-Fock solutions by dictating their configurations through some reference state. Numerical calculation is performed by using the Skyrme III. (author)
Hartree-Fock description of superdeformed states
International Nuclear Information System (INIS)
Dobaczewski, J.; Meyer, J.
1991-10-01
The discovery of superdeformation has been preceded by theoretical predictions made in Nilsson-Strutinsky calculations and a description of the phenomenon still constitutes an exciting challenge to the theory of nuclear collective motion. In particular, a determination of electromagnetic transition rates requires a knowledge of microscopic collective wave functions, which can be achieved by using the Hartree-Fock (HF) theory and the generator coordinate method (GCM). In this study we present results of our calculations concerning the properties and superdeformed states in the mercury region. Using the GCM, we diagonalize the microscopic two-body hamiltonian within the basis set of constrained HF+BCS wave functions. The GCM provides values for the energy of the ground and excited states including the shape isomer which take into account the effect of correlations in the collective degree of freedom. The GCM will also allow us to discuss the qualitative modifications of the shape isomeric stability as induced by changes in pairing correlations
Parallel scalability of Hartree-Fock calculations
Chow, Edmond; Liu, Xing; Smelyanskiy, Mikhail; Hammond, Jeff R.
2015-03-01
Quantum chemistry is increasingly performed using large cluster computers consisting of multiple interconnected nodes. For a fixed molecular problem, the efficiency of a calculation usually decreases as more nodes are used, due to the cost of communication between the nodes. This paper empirically investigates the parallel scalability of Hartree-Fock calculations. The construction of the Fock matrix and the density matrix calculation are analyzed separately. For the former, we use a parallelization of Fock matrix construction based on a static partitioning of work followed by a work stealing phase. For the latter, we use density matrix purification from the linear scaling methods literature, but without using sparsity. When using large numbers of nodes for moderately sized problems, density matrix computations are network-bandwidth bound, making purification methods potentially faster than eigendecomposition methods.
The spectrum of 12C in a multi-configuration Hartree-Fock Basis
International Nuclear Information System (INIS)
Amos, K.; Morrison, I.; Smith, R.; Schmid, K.W.
1981-01-01
The energy level spectrum of 12 C is calculated in a truncated but large shell model space of projected one particle-one hole Hartree Fock determinants using a realistic G-matrix. Predictions of electromagnetic decays and electron scattering form factors are compared with experimental values
Theories of the nuclear ground state beyond Hartree-Fock
International Nuclear Information System (INIS)
Gogny, D.
1979-01-01
Intensive efforts have been invested toward defining a microscopic approach, simple enough to render feasible systematic calculations of nuclear structure and of the some time sufficiently rich in information as to serve for updating traditional microscopic approaches to the collective excitations. Our starting point is the mean field approximation with density dependent effective forces. To describe the collective excitations we use the two well known extensions based on the H.F. theory namely the random phase approximation and the adiabatic approximation to the time dependent Hartree-Fock theory. The purpose of this paper is to show what sort of calculations can be effectively carried out in the frame of such fully self consistent approaches. (KBE) 891 KBE/KBE 892 ARA
Computational Nuclear Physics and Post Hartree-Fock Methods
Energy Technology Data Exchange (ETDEWEB)
Lietz, Justin [Michigan State University; Sam, Novario [Michigan State University; Hjorth-Jensen, M. [University of Oslo, Norway; Hagen, Gaute [ORNL; Jansen, Gustav R. [ORNL
2017-05-01
We present a computational approach to infinite nuclear matter employing Hartree-Fock theory, many-body perturbation theory and coupled cluster theory. These lectures are closely linked with those of chapters 9, 10 and 11 and serve as input for the correlation functions employed in Monte Carlo calculations in chapter 9, the in-medium similarity renormalization group theory of dense fermionic systems of chapter 10 and the Green's function approach in chapter 11. We provide extensive code examples and benchmark calculations, allowing thereby an eventual reader to start writing her/his own codes. We start with an object-oriented serial code and end with discussions on strategies for porting the code to present and planned high-performance computing facilities.
Spatial and Spin Symmetry Breaking in Semidefinite-Programming-Based Hartree-Fock Theory.
Nascimento, Daniel R; DePrince, A Eugene
2018-05-08
The Hartree-Fock problem was recently recast as a semidefinite optimization over the space of rank-constrained two-body reduced-density matrices (RDMs) [ Phys. Rev. A 2014 , 89 , 010502(R) ]. This formulation of the problem transfers the nonconvexity of the Hartree-Fock energy functional to the rank constraint on the two-body RDM. We consider an equivalent optimization over the space of positive semidefinite one-electron RDMs (1-RDMs) that retains the nonconvexity of the Hartree-Fock energy expression. The optimized 1-RDM satisfies ensemble N-representability conditions, and ensemble spin-state conditions may be imposed as well. The spin-state conditions place additional linear and nonlinear constraints on the 1-RDM. We apply this RDM-based approach to several molecular systems and explore its spatial (point group) and spin ( Ŝ 2 and Ŝ 3 ) symmetry breaking properties. When imposing Ŝ 2 and Ŝ 3 symmetry but relaxing point group symmetry, the procedure often locates spatial-symmetry-broken solutions that are difficult to identify using standard algorithms. For example, the RDM-based approach yields a smooth, spatial-symmetry-broken potential energy curve for the well-known Be-H 2 insertion pathway. We also demonstrate numerically that, upon relaxation of Ŝ 2 and Ŝ 3 symmetry constraints, the RDM-based approach is equivalent to real-valued generalized Hartree-Fock theory.
The Gogny-Hartree-Fock-Bogoliubov nuclear-mass model
Energy Technology Data Exchange (ETDEWEB)
Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium); Hilaire, S.; Girod, M.; Peru, S. [CEA, DAM, DIF, Arpajon (France)
2016-07-15
We present the Gogny-Hartree-Fock-Bogoliubov model which reproduces nuclear masses with an accuracy comparable with the best mass formulas. In contrast to the Skyrme-HFB nuclear-mass models, an explicit and self-consistent account of all the quadrupole correlation energies is included within the 5D collective Hamiltonian approach. The final rms deviation with respect to the 2353 measured masses is 789 keV in the 2012 atomic mass evaluation. In addition, the D1M Gogny force is shown to predict nuclear and neutron matter properties in agreement with microscopic calculations based on realistic two- and three-body forces. The D1M properties and its predictions of various observables are compared with those of D1S and D1N. (orig.)
A constrained Hartree-Fock-Bogoliubov equation derived from the double variational method
International Nuclear Information System (INIS)
Onishi, Naoki; Horibata, Takatoshi.
1980-01-01
The double variational method is applied to the intrinsic state of the generalized BCS wave function. A constrained Hartree-Fock-Bogoliubov equation is derived explicitly in the form of an eigenvalue equation. A method of obtaining approximate overlap and energy overlap integrals is proposed. This will help development of numerical calculations of the angular momentum projection method, especially for general intrinsic wave functions without any symmetry restrictions. (author)
Variational derivation of a time-dependent Hartree-Fock Hamiltonian
International Nuclear Information System (INIS)
Lichtner, P.C.; Griffin, J.J.; Schultheis, H.; Schultheis, R.; Volkov, A.B.
1979-01-01
The variational derivation of the time-dependent Hartree-Fock equation is reviewed. When norm-violating variations are included, a unique time-dependent Hartree-Fock Hamiltonian, which differs from that customarily used in time-dependent Hartree-Fock analyses, is implied. This variationally ''true'' Hartree-Fock Hamiltonian has the same expectation value as the exact Hamiltonian, equal to the average energy of the system. Since this quantity remains constant under time-dependent Hartree-Fock time evolution, we suggest the label ''constant '' for this form of time-dependent Hartree-Fock theory
Multiconfiguration Hartree-Fock calculations for complex atoms
International Nuclear Information System (INIS)
Fischer, C.F.
1984-01-01
The Hartree-Fock method has become a standard in atomic structure theory. Simpler methods are often compared with it when accessing their reliability or worth and the notion of correlation, which intuitively may be thought of as the correction needed to account for the fact that electrons do not move independently in a central field, is defined with respect to the Hartree-Fock method rather than some other independent-particle model. In fact, in an earlier article in this series, Fricke (Progress in Atomic Spectroscopy, Part A, Plenum Press (1978)), states, ''The so-called HF method is the basis of all good atomic calculations.'' In some sense, the Hartree-Fock method is the best method. The author briefly reviews its properties here. 67 references, 2 figures
Nuclear Hartree-Fock approximation testing and other related approximations
International Nuclear Information System (INIS)
Cohenca, J.M.
1970-01-01
Hartree-Fock, and Tamm-Dancoff approximations are tested for angular momentum of even-even nuclei. Wave functions, energy levels and momenta are comparatively evaluated. Quadripole interactions are studied following the Elliott model. Results are applied to Ne 20 [pt
Derivative discontinuity with localized Hartree-Fock potential
Energy Technology Data Exchange (ETDEWEB)
Nazarov, V. U. [Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Vignale, G. [Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)
2015-08-14
The localized Hartree-Fock potential has proven to be a computationally efficient alternative to the optimized effective potential, preserving the numerical accuracy of the latter and respecting the exact properties of being self-interaction free and having the correct −1/r asymptotics. In this paper we extend the localized Hartree-Fock potential to fractional particle numbers and observe that it yields derivative discontinuities in the energy as required by the exact theory. The discontinuities are numerically close to those of the computationally more demanding Hartree-Fock method. Our potential enjoys a “direct-energy” property, whereby the energy of the system is given by the sum of the single-particle eigenvalues multiplied by the corresponding occupation numbers. The discontinuities c{sub ↑} and c{sub ↓} of the spin-components of the potential at integer particle numbers N{sub ↑} and N{sub ↓} satisfy the condition c{sub ↑}N{sub ↑} + c{sub ↓}N{sub ↓} = 0. Thus, joining the family of effective potentials which support a derivative discontinuity, but being considerably easier to implement, the localized Hartree-Fock potential becomes a powerful tool in the broad area of applications in which the fundamental gap is an issue.
International Nuclear Information System (INIS)
Neese, Frank; Wennmohs, Frank; Hansen, Andreas; Becker, Ute
2009-01-01
In this paper, the possibility is explored to speed up Hartree-Fock and hybrid density functional calculations by forming the Coulomb and exchange parts of the Fock matrix by different approximations. For the Coulomb part the previously introduced Split-RI-J variant (F. Neese, J. Comput. Chem. 24 (2003) 1740) of the well-known 'density fitting' approximation is used. The exchange part is formed by semi-numerical integration techniques that are closely related to Friesner's pioneering pseudo-spectral approach. Our potentially linear scaling realization of this algorithm is called the 'chain-of-spheres exchange' (COSX). A combination of semi-numerical integration and density fitting is also proposed. Both Split-RI-J and COSX scale very well with the highest angular momentum in the basis sets. It is shown that for extended basis sets speed-ups of up to two orders of magnitude compared to traditional implementations can be obtained in this way. Total energies are reproduced with an average error of <0.3 kcal/mol as determined from extended test calculations with various basis sets on a set of 26 molecules with 20-200 atoms and up to 2000 basis functions. Reaction energies agree to within 0.2 kcal/mol (Hartree-Fock) or 0.05 kcal/mol (hybrid DFT) with the canonical values. The COSX algorithm parallelizes with a speedup of 8.6 observed for 10 processes. Minimum energy geometries differ by less than 0.3 pm in the bond distances and 0.5 deg. in the bond angels from their canonical values. These developments enable highly efficient and accurate self-consistent field calculations including nonlocal Hartree-Fock exchange for large molecules. In combination with the RI-MP2 method and large basis sets, second-order many body perturbation energies can be obtained for medium sized molecules with unprecedented efficiency. The algorithms are implemented into the ORCA electronic structure system
Koopmans' theorem in the Hartree-Fock method. General formulation
Plakhutin, Boris N.
2018-03-01
This work presents a general formulation of Koopmans' theorem (KT) in the Hartree-Fock (HF) method which is applicable to molecular and atomic systems with arbitrary orbital occupancies and total electronic spin including orbitally degenerate (OD) systems. The new formulation is based on the full set of variational conditions imposed upon the HF orbitals by the variational principle for the total energy and the conditions imposed by KT on the orbitals of an ionized electronic shell [B. N. Plakhutin and E. R. Davidson, J. Chem. Phys. 140, 014102 (2014)]. Based on these conditions, a general form of the restricted open-shell HF method is developed, whose eigenvalues (orbital energies) obey KT for the whole energy spectrum. Particular attention is paid to the treatment of OD systems, for which the new method gives a number of unexpected results. For example, the present method gives four different orbital energies for the triply degenerate atomic level 2p in the second row atoms B to F. Based on both KT conditions and a parallel treatment of atoms B to F within a limited configuration interaction approach, we prove that these four orbital energies, each of which is triply degenerate, are related via KT to the energies of different spin-dependent ionization and electron attachment processes (2p)N → (2p ) N ±1. A discussion is also presented of specific limitations of the validity of KT in the HF method which arise in OD systems. The practical applicability of the theory is verified by comparing KT estimates of the ionization potentials I2s and I2p for the second row open-shell atoms Li to F with the relevant experimental data.
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Rugles Cesar
2002-07-01
The present thesis is divided into two parts. The first part describes the many kind of the formalisms of the Generator Coordinate Hartree-Fock method (GCHFM) and second part describes the computational aspect applied to the GCHFM formalism in its discreet form. The major aim of this work is the development of an alternative method to non-linear parameters optimization (basis set) and later uses these optimized parameters to adjust the weight function into GCHFM method. The study of the weight function when N {yields} {infinity} (or for large N), where N represents the number of mesh, is important since the GCHFM theory in its continuous form depend on understanding of such behavior. In this thesis, a detailed study is carried out about the methodologies of the self-consistent solution of the GCHFM and some methodology aspects of non-linear parameters optimization. This work shows that the Generator Coordinate Hartree-Fock method is general and it has as particular case the Hartree-Fock Roothaan method. Some possible variations or combinations around of the characteristics of the GCHFM and a comparison with conventional SCF procedure are reported in this thesis. The piecewise weight function method developed in this work shows to be very good for collective parameter optimizations of the Generator Coordinate (GC). The GCHFM calculations are necessary restrict (GCM-RHF), especially when the calculated value energies approach of its numerical values or Hartree-Fock limit. In the optimization methods of state functions for atomic electronic systems is very common the application of the gradient method and its efficacy is not contested. However, the method describes above allow us to obtain results as good as the gradient method. The basis set generated using the piecewise weight function method for Gaussian type function were used in the Restrict Hartree-Fock (RHF) calculations to obtain the total energies for some atomic electronic systems, such as neutron atoms and
Hartree-Fock states in the thermodynamic limit
International Nuclear Information System (INIS)
Aguilera-Navarro, V.C.; Llano, M. de; Peltier, S.; Plastino, A.
1976-01-01
Two infinite families of two-parameter generalized Overhauser orbitals are introduced and shown to explicitly satisfy, for occupied states, the self-consistent Hartree-Fock equations in the thermodynamic limit. For an attractive delta interaction, they give lower Hartree-Fock energy than the usual plane-wave solutions, even for relatively weak coupling and/or low density. The limiting members (possessing an infinite number of harmonics) of both families appear to tend to a 'classical static lattice' state. The related density profiles and energy expressions are calculated as functions of the two new parameters. A direct-variation with respect to these parameters was done numerically and results are presented graphically. (Author) [pt
How good are Hartree-Fock charge densities
International Nuclear Information System (INIS)
Campi, X.
1975-01-01
The principle characteristics of Hartree-Fock charge densities (mean square radius, surface thickness, quantum fluctuation) calculated using different effective interactions are discussed in terms of their nuclear matter properties (Fermi momentum, effective mass, incompressibility). A comparison with the experimental charge distributions is made. Differences between the charge densities of neighbouring nuclei (isotope and isotone shifts) are also considered and the main factors governing these effects are discussed [fr
The Hartree-Fock seniority method and its foundation
International Nuclear Information System (INIS)
Gomez, J.M.G.; Prieto, C.
1987-01-01
The seniority scheme is discussed in the framewok of quasi-spin formalism. It is shown that the ground-state wave function of the seniority scheme can be determined self-consistently from a set of Hartree-Fock seniority equations derived from the variational prinicple. The method takes into account the mean-field and the pairing correlations in nuclei at the same time. Angular momentum and particle number are exactly conserved. (author)
General multi-configuration Hartree--Fock program: MCHF77
International Nuclear Information System (INIS)
Fischer, C.F.
1977-11-01
This technical report contains a listing of a general program for multi-configuration Hartree--Fock (MCHF) calculations, including its documentation. Several examples are given showing how the program may be used. Typical output for several cases is also presented. This program has been tested over an extended period of time for a large variety of cases. This program is written for the IBM 360 or 370 in double-precision arithmetic
International Nuclear Information System (INIS)
Barbosa, Rugles Cesar
2002-01-01
The present thesis is divided into two parts. The first part describes the many kind of the formalisms of the Generator Coordinate Hartree-Fock method (GCHFM) and second part describes the computational aspect applied to the GCHFM formalism in its discreet form. The major aim of this work is the development of an alternative method to non-linear parameters optimization (basis set) and later uses these optimized parameters to adjust the weight function into GCHFM method. The study of the weight function when N → ∞ (or for large N), where N represents the number of mesh, is important since the GCHFM theory in its continuous form depend on understanding of such behavior. In this thesis, a detailed study is carried out about the methodologies of the self-consistent solution of the GCHFM and some methodology aspects of non-linear parameters optimization. This work shows that the Generator Coordinate Hartree-Fock method is general and it has as particular case the Hartree-Fock Roothaan method. Some possible variations or combinations around of the characteristics of the GCHFM and a comparison with conventional SCF procedure are reported in this thesis. The piecewise weight function method developed in this work shows to be very good for collective parameter optimizations of the Generator Coordinate (GC). The GCHFM calculations are necessary restrict (GCM-RHF), especially when the calculated value energies approach of its numerical values or Hartree-Fock limit. In the optimization methods of state functions for atomic electronic systems is very common the application of the gradient method and its efficacy is not contested. However, the method describes above allow us to obtain results as good as the gradient method. The basis set generated using the piecewise weight function method for Gaussian type function were used in the Restrict Hartree-Fock (RHF) calculations to obtain the total energies for some atomic electronic systems, such as neutron atoms and ions in
Tensor numerical methods in quantum chemistry: from Hartree-Fock to excitation energies.
Khoromskaia, Venera; Khoromskij, Boris N
2015-12-21
We resume the recent successes of the grid-based tensor numerical methods and discuss their prospects in real-space electronic structure calculations. These methods, based on the low-rank representation of the multidimensional functions and integral operators, first appeared as an accurate tensor calculus for the 3D Hartree potential using 1D complexity operations, and have evolved to entirely grid-based tensor-structured 3D Hartree-Fock eigenvalue solver. It benefits from tensor calculation of the core Hamiltonian and two-electron integrals (TEI) in O(n log n) complexity using the rank-structured approximation of basis functions, electron densities and convolution integral operators all represented on 3D n × n × n Cartesian grids. The algorithm for calculating TEI tensor in a form of the Cholesky decomposition is based on multiple factorizations using algebraic 1D "density fitting" scheme, which yield an almost irreducible number of product basis functions involved in the 3D convolution integrals, depending on a threshold ε > 0. The basis functions are not restricted to separable Gaussians, since the analytical integration is substituted by high-precision tensor-structured numerical quadratures. The tensor approaches to post-Hartree-Fock calculations for the MP2 energy correction and for the Bethe-Salpeter excitation energies, based on using low-rank factorizations and the reduced basis method, were recently introduced. Another direction is towards the tensor-based Hartree-Fock numerical scheme for finite lattices, where one of the numerical challenges is the summation of electrostatic potentials of a large number of nuclei. The 3D grid-based tensor method for calculation of a potential sum on a L × L × L lattice manifests the linear in L computational work, O(L), instead of the usual O(L(3) log L) scaling by the Ewald-type approaches.
Basic and heavy ion scattering in time dependent Hartree-Fock Theory
International Nuclear Information System (INIS)
Weiss, M.S.
1984-01-01
Time Dependent Hartree-Fock theory, TDHF, is the most sophisticated, microscopic approach to nuclear dynamics yet practiced. Although it is far from a description of nature it does allow us to examine multiply interactive many-body systems semi quantum mechanically and to visualize otherwise covert processes. Some of the properties of the TDHF equations are stated leaving the interested reader to one of several excellent review articles for the derivations. Some of the applications to the collision of heavy ions are briefly described
Time-dependent Hartree-Fock dynamics and phase transition in Lipkin-Meshkov-Glick model
International Nuclear Information System (INIS)
Kan, K.; Lichtner, P.C.; Dworzecka, M.; Griffin, J.J.
1980-01-01
The time-dependent Hartree-Fock solutions of the two-level Lipkin-Meshkov-Glick model are studied by transforming the time-dependent Hartree-Fock equations into Hamilton's canonical form and analyzing the qualitative structure of the Hartree-Fock energy surface in the phase space. It is shown that as the interaction strength increases these time-dependent Hartree-Fock solutions undergo a qualitative change associated with the ground state phase transition previously studied in terms of coherent states. For two-body interactions stronger than the critical value, two types of time-dependent Hartree-Fock solutions (the ''librations'' and ''rotations'' in Hamilton's mechanics) exist simultaneously, while for weaker interactions only the rotations persist. It is also shown that the coherent states with the maximum total pseudospin value are determinants, so that time-dependent Hartree-Fock analysis is equivalent to the coherent state method
International Nuclear Information System (INIS)
Libert, J.; Girod, M.; Delaroche, J-P.; Berger, J-F.; Romain, P.; Peru, S.
1997-01-01
The superdeformed bands of the nuclei in the region A = 190 were described by two microscopic approaches using Gogny D1 finite range interaction. The first one consists in building a Bohr Hamiltonian in the framework of Gauss overlap approximation (GOA) of the generator-coordinate method, starting from Hartree-Fock-Bogolyubov solutions under quadrupole constraints. This collective Hamiltonian microscopically determined for five quadrupolar variables is then diagonalized by a projection method on a collective based adapted to the large variety of the deformations to be considered. A special attention was given to the precise definition of the under-barrier collective wavefunctions (for which an original method of solving the collective Schroedinger equation was developed) in order to described correctly the lifetime of the shape isomeric states. The other approach, that of Routhian is based also on the Hartree-Fock-Bogolyubov approximation. The calculations are carried out with and without restoring the broken symmetry associated to the particle numbers (as given by Lipkin-Nogami). The results (excitation energies, moments of inertia, etc...) of the two calculation methods are compared with most recent experimental data. The existence of the superdeformed bands corresponding to vibrational excitations similar to those appearing in β and γ bands is proposed
Constrained Hartree-Fock and beyond
International Nuclear Information System (INIS)
Berger, J.F.; Girod, M.; Gogny, D.
1989-01-01
Completely microscopic descriptions of the fission phenomenon based on the nuclear mean field theory and its extensions are reviewed. The basic ideas underlying this kind of approach and the way one can set up a consistent microscopic dynamical model of the low energy fission process are presented. The main difficulties encountered in earlier calculations when trying to reproduce experimental fission barriers and to account for scission are recalled. We describe the method by which these difficulties have been overcome and discuss recent results. They concern a proposed interpretation for the scission mechanism and 'cold fission' events. Other issues like adiabaticity in the descent from the second saddle to scission and odd-even effects in cold fission are also discussed. (orig.)
The Hartree-Fock approximation for s-d shell even-even nuclei with N different of Z
International Nuclear Information System (INIS)
Oliveira, P.C. de.
1981-02-01
Using the Hartree-Fock approximation method for 22 Ne, 26 Mg and 30 Si nuclei with different kinds of two-body interactions, the electric quadrupole moments and projected energy levels, of angular momentum J=0,2,4,6..., are determined. The Peierls-Yoccoz projection m ethod is used to determine the wave function with well-defined angular momentum. A comparison is made, with the experimental results and the ones obtained by other authors. (Author) [pt
Time Dependent Hartree Fock Equation: Gateway to Nonequilibrium Plasmas
International Nuclear Information System (INIS)
Dufty, James W.
2007-01-01
This is the Final Technical Report for DE-FG02-2ER54677 award 'Time Dependent Hartree Fock Equation - Gateway to Nonequilibrium Plasmas'. Research has focused on the nonequilibrium dynamics of electrons in the presence of ions, both via basic quantum theory and via semi-classical molecular dynamics (MD) simulation. In addition, fundamental notions of dissipative dynamics have been explored for models of grains and dust, and for scalar fields (temperature) in turbulent edge plasmas. The specific topics addressed were Quantum Kinetic Theory for Metallic Clusters, Semi-classical MD Simulation of Plasmas , and Effects of Dissipative Dynamics.
Relativity and pseudopotentials in the Hartree-Fock-Slater method
International Nuclear Information System (INIS)
Snijders, J.G.
1979-01-01
The methodological problems involved in electronic structure determinations of compounds containing heavy elements by the Hartree-Fock-Slater scheme are investigated. It is shown that the effect of the inner electrons can be simulated by a so called pseudopotential, so that only the valence electrons have to be treated explicitly which constitutes a considerable reduction of computation time. It is further shown that a pseudopotential calculation is able to achieve an accuracy that is comparable to the results of a calculation including the core. (Auth.)
Semiclassical expansions of the nuclear relativistic Hartree-Fock theory
International Nuclear Information System (INIS)
Weigel, M.K.; Haddad, S.
1991-01-01
Semiclassical expansions for Green functions, self-energy, phase-space density and density are given and discussed. The many-body problem was treated in the relativistic Hartree-Fock approximation with a Lagrangian with a standard OBE potential structure including the possibility of space-dependent couplings. The expansions are obtained by formulating the many-body problem in the mixed position-momentum (Wigner) representation and application of the (h/2π)-Wigner-Kirkwood expansion scheme. The resulting self-consistency problems for the zeroth and second order are formulated in three versions. (author)
Hartree-Fock-Bogoliubov approximation for finite systems
International Nuclear Information System (INIS)
Bulgac, A.
1980-08-01
The features of the spectrum of the Hartree-Fock-Bogoliubov equations are examined. Special attention is paid to the asymptotic behaviours of the single quasiparticle wave functions (s.qp.w.fs.), matter density distribution and density of the pair condensate. It is shown that, due to the coupling between hole and particle, the sufficiently deeply bound hole states acquire a width and consequently have to be treated as continuum states. The proper normalization of the s.qp.w.fs. is discussed. (author)
Exponential convergence and acceleration of Hartree-Fock calculations
International Nuclear Information System (INIS)
Bonaccorso, A.; Di Toro, M.; Lomnitz-Adler, J.
1979-01-01
It is shown that one can expect an exponential behaviour for the convergence of the Hartree-Fock solution during the HF iteration procedure. This property is used to extrapolate some collective degrees of freedom, in this case the shape, in order to speed up the self-consistent calculation. For axially deformed nuclei the method is applied to the quadrupole moment which corresponds to a simple scaling transformation on the single particle wave functions. Results are shown for the deformed nuclei 20 Ne and 28 Si with a Skyrme interaction. (Auth.)
A Hartree-Fock program for atomic structure calculations
International Nuclear Information System (INIS)
Mitroy, J.
1999-01-01
The Hartree-Fock equations for a general open shell atom are described. The matrix equations that result when the single particle orbitals are written in terms of a linear combination of analytic basis functions are derived. Attention is paid to the complexities that occur when open shells are present. The specifics of a working FORTRAN program which is available for public use are described. The program has the flexibility to handle either Slater-type orbitals or Gaussian-type orbitals. It can be obtained over the internet at http://lacebark.ntu.edu.au/j_mitroy/research/atomic.htm Copyright (1999) CSIRO Australia
Cluster modeling of solid state defects and adsorbates: Beyond the Hartree-Fock level
International Nuclear Information System (INIS)
Kunz, A.B.
1990-01-01
The use of finite clusters of atoms to represent the physically interesting portion of a condensed matter system has been an accepted technique for the past two decades. Physical systems have been studied in this way using both density functional and Hartree-Fock methodologies, as well as a variety of empirical or semiempirical techniques. In this article, the author concentrates on the Hartree-Fock based methods. The attempt here is to construct a theoretical basis for the inclusion of correlation corrections in such an approach, as well as a strategy by which the limits of a finite cluster may be transcended in such a study. The initial appeal will be to a modeling approach, but methods to convert the model to a self-contained theory will be described. It will be seen for the case of diffusion of large ions in solids that such an approach is quite useful. A further study of the case of adsorption of rare gas atoms on simple metals will demonstrate the value of inclusion of electron correlation
Energy Levels and B(E2) transition rates in the Hartree-Fock approximation with the Skyrme force
International Nuclear Information System (INIS)
Oliveira, D.R. de; Mizrahi, S.S.
1976-11-01
The Hartree-Fock approximation with the Skyrme force is applied to the A = 4n type of nuclei in the s-d shell. Energy levels and electric quadrupole transition probabilities within the ground states band are calculated from the projected states of good angular momentum. Strong approximations are made but the results concerning the spectra are better than those obtained with more sophisticated density independent two-body interactions. The transition rates are less sensitive to the interaction, as previously verified
Hartree-Fock-Bogoliubov model: a theoretical and numerical perspective
International Nuclear Information System (INIS)
Paul, S.
2012-01-01
This work is devoted to the theoretical and numerical study of Hartree-Fock-Bogoliubov (HFB) theory for attractive quantum systems, which is one of the main methods in nuclear physics. We first present the model and its main properties, and then explain how to get numerical solutions. We prove some convergence results, in particular for the simple fixed point algorithm (sometimes called Roothaan). We show that it converges, or oscillates between two states, none of them being a solution. This generalizes to the HFB case previous results of Cances and Le Bris for the simpler Hartree-Fock model in the repulsive case. Following these authors, we also propose a relaxed constraint algorithm for which convergence is guaranteed. In the last part of the thesis, we illustrate the behavior of these algorithms by some numerical experiments. We first consider a system where the particles only interact through the Newton potential. Our numerical results show that the pairing matrix never vanishes, a fact that has not yet been proved rigorously. We then study a very simplified model for protons and neutrons in a nucleus. (author)
International Nuclear Information System (INIS)
Maedler, P.
1984-01-01
The review describes the application of the time-dependent Hartree--Fock method to the description of heavy-ion interactions at energies of order 10 MeV/nucleon. The fundamentals of the method are presented and qualitative properties of its results are discussed. Realistic calculations of fusion reactions, deep inelastic collisions, and particle emission are presented and compared with the corresponding experimental data. Various approaches that generalize the method by taking into account correlations are considered
Functionals Hartree-Fock equations in the Schrodinger representation of quantum field theory
International Nuclear Information System (INIS)
Gamboa, J.
1989-08-01
Hartree-Fock equations for a scalar field theory in the Schrodinger representation are derived. It is shown that renormalization of the total energy in the functional Schrodinger equation is enterely contained in the eigenvalues of the Hartree-Fock hamiltonian. (A.C.A.S.) [pt
Extended Hartree-Fock-Bogoliubov theory for degenerate Bose systems
International Nuclear Information System (INIS)
Tommasini, Paolo; Passos, E J V de; Pires, M O C; Piza, A F R de Toledo
2005-01-01
An extension of the Hartree-Fock-Bogoliubov (HFB) theory of degenerate Bose systems in which the coupling between one and two quasi-particles is taken into account is developed. The excitation operators are written as linear combinations of one and two HFB quasi-particles. Excitation energies and quasi-particle amplitudes are given by generalized Bogoliubov equations. The excitation spectrum has two branches. The first one is a discrete branch which is gapless and has a phonon character at large wavelength and, contrarily to HFB, is always stable. This branch is detached from a second, continuum branch whose threshold, at fixed total momentum, coincides with the two quasi-particle threshold of the HFB theory. The gap between the two branches at P = 0 is twice the HFB gap, which thus provides for the relevant energy scale. Numerical results for a specific case are given
Self-consistent Hartree-Fock RPA calculations in 208Pb
Taqi, Ali H.; Ali, Mohammed S.
2018-01-01
The nuclear structure of 208Pb is studied in the framework of the self-consistent random phase approximation (SCRPA). The Hartree-Fock mean field and single particle states are used to implement a completely SCRPA with Skyrme-type interactions. The Hamiltonian is diagonalised within a model space using five Skyrme parameter sets, namely LNS, SkI3, SkO, SkP and SLy4. In view of the huge number of the existing Skyrme-force parameterizations, the question remains which of them provide the best description of data. The approach attempts to accurately describe the structure of the spherical even-even nucleus 208Pb. To illustrate our approach, we compared the binding energy, charge density distribution, excitation energy levels scheme with the available experimental data. Moreover, we calculated isoscalar and isovector monopole, dipole, and quadrupole transition densities and strength functions.
Time-dependent--S-matrix Hartree-Fock theory of complex reactions
International Nuclear Information System (INIS)
Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.
1980-01-01
Some limitations of the conventional time-dependent Hartree-Fock method for describing complex reactions are noted, and one particular ubiquitous defect is discussed in detail: the post-breakup spurious cross channel correlations which arise whenever several asymptotic reaction channels must be simultaneously described by a single determinant. A reformulated time-dependent--S-matrix Hartree-Fock theory is proposed, which obviates this difficulty. Axiomatic requirements minimal to assure that the time-dependent--S-matrix Hartree-Fock theory represents an unambiguous and physically interpretable asymptotic reaction theory are utilized to prescribe conditions upon the definition of acceptable asymptotic channels. That definition, in turn, defines the physical range of the time-dependent--S-matrix Hartree-Fock theory to encompass the collisions of mathematically well-defined ''time-dependent Hartree-Fock droplets.'' The physical properties of these objects then circumscribe the content of the Hartree-Fock single determinantal description. If their periodic vibrations occur for continuous ranges of energy then the resulting ''classical'' time-dependent Hartree-Fock droplets are seen to be intrinsically dissipative, and the single determinantal description of their collisions reduces to a ''trajectory'' theory which can describe the masses and relative motions of the fragments but can provide no information about specific asymptotic excited states beyond their constants of motion, or the average properties of the limit, if it exists, of their equilibrization process. If, on the other hand, the periodic vibrations of the time-dependent Hartree-Fock droplets are discrete in energy, then the time-dependent--S-matrix Hartree-Fock theory can describe asymptotically the time-average properties of the whole spectrum of such periodic vibrations
Relativistic Hartree-Fock theory. Part I: density-dependent effective Lagrangians
Energy Technology Data Exchange (ETDEWEB)
LongWen Hui [School of Physics, Peking University, 100871 Beijing (China)]|[CNRS-IN2P3, UMR 8608, F-91406 Orsay Cedex (France)]|[Univ Paris-Sud, F-91405 Orsay (France); Giai, Nguyen Van [CNRS-IN2P3, UMR 8608, F-91406 Orsay Cedex (France)]|[Univ Paris-Sud, F-91405 Orsay (France); Meng, Jie [School of Physics, Peking University, 100871 Beijing (China)]|[Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing (China)]|[Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Accelerator, 730000 Lanzhou (China)
2006-10-15
Effective Lagrangians suitable for a relativistic Hartree-Fock description of nuclear systems are presented. They include the 4 effective mesons {sigma}, {omega}, {rho} and {pi} with density-dependent meson-nucleon couplings. The criteria for determining the model parameters are the reproduction of the binding energies in a number of selected nuclei, and the bulk properties of nuclear matter (saturation point, compression modulus, symmetry energy). An excellent description of nuclear binding energies and radii is achieved for a range of nuclei encompassing light and heavy systems. The predictions of the present approach compare favorably with those of existing relativistic mean field models, with the advantage of incorporating the effects of pion-nucleon coupling. (authors)
Derivation of an adiabatic time-dependent Hartree-Fock formalism from a variational principle
International Nuclear Information System (INIS)
Brink, D.M.; Giannoni, M.J.; Veneroni, M.
1975-10-01
A derivation of the adiabatic time-dependent Hartree-Fock formalism is given, which is based on a variational principle analogous to Hamilton's principle in classical mechanics. The method leads to a Hamiltonian for collective motion which separates into a potential and a kinetic energy and gives mass and potential parameters in terms of the nucleon-nucleon interaction. The adiabatic approximation assumes slow motion but not small amplitudes and can therefore describe anharmonic effects. The RPA is a limiting case where both amplitudes and velocities are small. The variational approach provides a consistent way of extracting coordinated and momenta from the density matrix and of obtaining equations of motion when particular trial forms for this density matrix are chosen. One such choice leads to Thouless-Valatin formula. An other choice leads to irrotational hydrodynamics [fr
International Nuclear Information System (INIS)
Brack, M.
1981-01-01
Strutinsky's shell-correction method is investigated in the framework of the microscopial Hartree-Fock-Bogoliubov method at finite temperature HFBT. Applying the Strutinsky energy averaging consistently to the normal and abnormal density matrices and to the entropy, we define a self-consistently average HFBT system as the solution of a variational problem. From the latter we derive the generalized Strutinsky energy theorem and the explicit expressions for the shell correction of a statistically excited system of BCS quasiparticles. Using numerical results of HF calculations, we demonstrate the convergence of the Strutinsky expansion and estimate the validity of the partical shell-correction approach. We also discuss the close connections of the Strutinsky energy averaging with semiclassical expansions and their usefulness for solving the average nuclear self-consistency problem. In particular we argue that the Hohenberg-Kohn theorem should hold for the averaged HFBT system and we thus provide a justification of the use of semiclassical density functionals. (orig.)
International Nuclear Information System (INIS)
Ferrari, R.; I.N.F.N., Trento
1994-01-01
The formalism introduced in a previous paper is used for discussing the Coulomb interaction of many electrons moving in two space-dimensions in the presence of a strong magnetic field. The matrix element of the coulomb interaction is evaluated in the new basis, whose states are invariant under discrete translations. This paper is devoted to the case of low filling factor, thus the authors limit themselves to the lowest Landau level and to spins all oriented along the magnetic field. For the case of filling factor ν f = 1/u they give an Ansatz on the state of many electrons which provides a good approximated solution of the Hartree-Fock equation. For general filling factor ν f = u'/u a trial state is given which converges very rapidly to a solution of the self-consistent equation. They generalize the Hartree-Fock equation by considering some correlation: all quantum states are allowed for the u' electrons with the same translation quantum numbers. Numerical results are given for the mean energy and the energy bands, for some values of the filling factor (ν f = 1/2, 1/3, 2/3, 1/4, 3/4, 1/5, 2/5, 3/5, 4/5). The results agree numerically with the Charge Density Wave approach. The boundary conditions are shown to be very important: only large systems (degeneracy of Landau level over 200) are not affected by the boundaries. Therefore results obtained on small scale systems are somewhat unreliable. The relevance of the results for the Fractional Quantum Hall Effect is briefly discussed
International Nuclear Information System (INIS)
Thomaz, M.T.; Toledo Piza, A.F.R. de
1994-01-01
We show that the Hartree-Fock-Bogoliubov (alias Gaussian) approximation of the initial condition problem of the Fermionic Anharmonic Oscillator i equivalent to a bosonic Hamiltonian system of two classical spin. (author)
Directory of Open Access Journals (Sweden)
Thomas Gomez
2018-04-01
Full Text Available Atomic structure of N-electron atoms is often determined by solving the Hartree-Fock equations, which are a set of integro-differential equations. The integral part of the Hartree-Fock equations treats electron exchange, but the Hartree-Fock equations are not often treated as an integro-differential equation. The exchange term is often approximated as an inhomogeneous or an effective potential so that the Hartree-Fock equations become a set of ordinary differential equations (which can be solved using the usual shooting methods. Because the Hartree-Fock equations are an iterative-refinement method, the inhomogeneous term relies on the previous guess of the wavefunction. In addition, there are numerical complications associated with solving inhomogeneous differential equations. This work uses matrix methods to solve the Hartree-Fock equations as an integro-differential equation. It is well known that a derivative operator can be expressed as a matrix made of finite-difference coefficients; energy eigenvalues and eigenvectors can be obtained by using linear-algebra packages. The integral (exchange part of the Hartree-Fock equation can be approximated as a sum and written as a matrix. The Hartree-Fock equations can be solved as a matrix that is the sum of the differential and integral matrices. We compare calculations using this method against experiment and standard atomic structure calculations. This matrix method can also be used to solve for free-electron wavefunctions, thus improving how the atoms and free electrons interact. This technique is important for spectral line broadening in two ways: it improves the atomic structure calculations, and it improves the motion of the plasma electrons that collide with the atom.
On the problem of representability and the Bogolyubov-Hartree-Fock theory
Energy Technology Data Exchange (ETDEWEB)
Knoerr, Hans Konrad
2013-11-22
well-known that the generalized one-particle density matrix of a pure quasifree fermion state is a projection, and uniquely determines this pure quasifree state. We show that for fermions only pure quasifree states have a generalized one-particle density matrix which is a projection, and a similar statement for bosons which is the third main result. Chapter 4 is concerned with fermion representability conditions and a relation to the fermion correlation inequalities. After two introductory sections specifying the problem and notation, we derive the representability conditions up to second order for fermions. We explain that these basic conditions on the one- and two-particle density matrices, namely the admissibility and the G-, P-, and Q-conditions, arise from certain expectation values of polynomials of degree two in fermion creation and annihilation operators. Furthermore we verify that there are no further independent conditions that can be obtained that way. The main result proven in Chapter 4 is the theorem stating that the admissibility, and the G- and P-conditions imply the fermion correlation inequality which was used to derive a lower bound to the ground state energy. This lower bound is equal to the Hartree-Fock energy minus an error term which is small in the limit of large particle numbers. Thus a similar lower bound can already been obtained if one just requires the representability conditions mentioned above. In the last chapter we study representability conditions for fermions. There are several different versions of representability conditions, but to our knowledge all of them use the Fock representation of the canonical anticommutation relations. In Chapter 5 we reformulate the representability conditions up to third order using Grassmann integrals. While Grassmann integration is a very common method in quantum field theory, representability conditions from quantum chemistry have not been studied within this framework. This transcription in another
On the problem of representability and the Bogolyubov-Hartree-Fock theory
International Nuclear Information System (INIS)
Knoerr, Hans Konrad
2013-01-01
well-known that the generalized one-particle density matrix of a pure quasifree fermion state is a projection, and uniquely determines this pure quasifree state. We show that for fermions only pure quasifree states have a generalized one-particle density matrix which is a projection, and a similar statement for bosons which is the third main result. Chapter 4 is concerned with fermion representability conditions and a relation to the fermion correlation inequalities. After two introductory sections specifying the problem and notation, we derive the representability conditions up to second order for fermions. We explain that these basic conditions on the one- and two-particle density matrices, namely the admissibility and the G-, P-, and Q-conditions, arise from certain expectation values of polynomials of degree two in fermion creation and annihilation operators. Furthermore we verify that there are no further independent conditions that can be obtained that way. The main result proven in Chapter 4 is the theorem stating that the admissibility, and the G- and P-conditions imply the fermion correlation inequality which was used to derive a lower bound to the ground state energy. This lower bound is equal to the Hartree-Fock energy minus an error term which is small in the limit of large particle numbers. Thus a similar lower bound can already been obtained if one just requires the representability conditions mentioned above. In the last chapter we study representability conditions for fermions. There are several different versions of representability conditions, but to our knowledge all of them use the Fock representation of the canonical anticommutation relations. In Chapter 5 we reformulate the representability conditions up to third order using Grassmann integrals. While Grassmann integration is a very common method in quantum field theory, representability conditions from quantum chemistry have not been studied within this framework. This transcription in another
Energy Technology Data Exchange (ETDEWEB)
Bernardos, P. [Universidad de Cantabria, Departamento de Matematica Aplicada y Ciencias de la Computacion, 39005, Santander (Spain); Fomenko, V.N. [St Petersburg University for Railway Engineering, Department of Mathematics, 190031, St Petersburg (Russian Federation); Marcos, S.; Niembro, R. [Universidad de Cantabria, Departamento de Fisica Moderna, 39005, Santander (Spain); Lopez-Quelle, M. [Universidad de Cantabria, Departamento de Fisica Aplicada, 39005, Santander (Spain); Savushkin, L.N. [St Petersburg University for Telecommunications, Department of Physics, 191186, St Petersburg (Russian Federation)
2001-02-01
An effective nuclear model describing {omega}-, {rho}- and axial-mesons as gauge fields is applied to nuclear matter in the relativistic Hartree-Fock approximation. The isoscalar two-pion exchange is simulated by a scalar field s similar to that used in the conventional relativistic mean-field approach. Two more scalar fields are essential ingredients of the present treatment: the {sigma}-field, the chiral partner of the pion, and the {sigma}-field, the Higgs field for the {omega}-meson. Two versions of the model are used depending on whether the {sigma}-field is considered as a dynamical variable or 'frozen', by taking its mass as infinite. The model contains four free parameters in the first case and three in the second one which are fitted to the nuclear matter saturation conditions. The nucleon and meson effective masses, compressibility modulus and symmetry energy are calculated. The results prove the reliability of the Dirac-Hartree-Fock approach within the linear realization of the chiral symmetry. (author)
Excess Charge for Pseudo-relativistic Atoms in Hartree-Fock Theory
DEFF Research Database (Denmark)
Dall'Acqua, Anna; Solovej, Jan Philip
2010-01-01
We prove within the Hartree-Fock theory of pseudo-relativistic atoms that the maximal negative ionization charge and the ionization energy of an atom remain bounded independently of the nuclear charge $Z$ and the fine structure constant $\\alpha$ as long as $Z\\alpha$ is bounded.......We prove within the Hartree-Fock theory of pseudo-relativistic atoms that the maximal negative ionization charge and the ionization energy of an atom remain bounded independently of the nuclear charge $Z$ and the fine structure constant $\\alpha$ as long as $Z\\alpha$ is bounded....
The total Hartree-Fock energy-eigenvalue sum relationship in atoms
International Nuclear Information System (INIS)
Sen, K.D.
1979-01-01
Using the well known relationships for the isoelectronic changes in the total Hartree-Fock energy, nucleus-electron attraction energy and electron-electron repulsion energy in atoms a simple polynomial expansion in Z is obtained for the sum of the eigenvalues which can be used to calculate the total Hartree-Fock energy. Numerical results are presented for 2-10 electron series to show that the present relationship is a better approximation than the other available energy-eigenvalue relationships. (author)
Instability of the cranked Hartree-Fock-Bogoliubov field in backbending region
International Nuclear Information System (INIS)
Horibata, Takatoshi; Onishi, Naoki.
1982-01-01
The stability condition of the cranked Hartree-Fock-Bogoliubov field is examined explicitly by solving the eigenvalue equation for the second order variation of the energy, which is reduced to an algebraic equation through a coupled dispersion formula. We confirm that the Hartree-Fock-Bogoliubov field is unstable in the backbending region of an irregular rotational band, even though the frequency of the softest random phase approximation mode always has a positive value. We investigate properties of the softest mode in detail. (author)
Density Functional Theory versus the Hartree-Fock Method: Comparative Assessment
International Nuclear Information System (INIS)
Amusia, M.Ya.; Shaginyan, V.R.; Msezane, A.Z.
2003-01-01
We compare two different approaches to investigations of many-electron systems. The first is the Hartree-Fock (HF) method and the second is the Density Functional Theory (DFT). Overview of the main features and peculiar properties of the HF method are presented. A way to realize the HF method within the Kohn-Sham (KS) approach of the DFT is discussed. We show that this is impossible without including a specific correlation energy, which is defined by the difference between the sum of the kinetic and exchange energies of a system considered within KS and HF, respectively. It is the nonlocal exchange potential entering the HF equations that generates this correlation energy. We show that the total correlation energy of a finite electron system, which has to include this correlation energy, cannot be obtained from considerations of uniform electron systems. The single-particle excitation spectrum of many-electron systems is related to the eigenvalues of the corresponding KS equations. We demonstrate that this spectrum does not coincide in general with the eigenvalues of KS or HF equations
Density Functional Theory versus the Hartree-Fock Method: Comparative Assessment
Energy Technology Data Exchange (ETDEWEB)
Amusia, M.Ya.; Shaginyan, V.R. [The Hebrew University, Jerusalem (Israel); Msezane, A.Z. [Clark Atlanta Univ., Atlanta, GA (United States). Center for Theoretical Studies of Physical Systems
2003-12-01
We compare two different approaches to investigations of many-electron systems. The first is the Hartree-Fock (HF) method and the second is the Density Functional Theory (DFT). Overview of the main features and peculiar properties of the HF method are presented. A way to realize the HF method within the Kohn-Sham (KS) approach of the DFT is discussed. We show that this is impossible without including a specific correlation energy, which is defined by the difference between the sum of the kinetic and exchange energies of a system considered within KS and HF, respectively. It is the nonlocal exchange potential entering the HF equations that generates this correlation energy. We show that the total correlation energy of a finite electron system, which has to include this correlation energy, cannot be obtained from considerations of uniform electron systems. The single-particle excitation spectrum of many-electron systems is related to the eigenvalues of the corresponding KS equations. We demonstrate that this spectrum does not coincide in general with the eigenvalues of KS or HF equations.
Madsen, Lars Bojer; Jensen, Frank; Dnestryan, Andrey I.; Tolstikhin, Oleg I.
2017-07-01
In the leading-order approximation of the weak-field asymptotic theory (WFAT), the dependence of the tunneling ionization rate of a molecule in an electric field on its orientation with respect to the field is determined by the structure factor of the ionizing molecular orbital. The WFAT yields an expression for the structure factor in terms of a local property of the orbital in the asymptotic region. However, in general quantum chemistry approaches molecular orbitals are expanded in a Gaussian basis which does not reproduce their asymptotic behavior correctly. This hinders the application of the WFAT to polyatomic molecules, which are attracting increasing interest in strong-field physics. Recently, an integral-equation approach to the WFAT for tunneling ionization of one electron from an arbitrary potential has been developed. The structure factor is expressed in an integral form as a matrix element involving the ionizing orbital. The integral is not sensitive to the asymptotic behavior of the orbital, which resolves the difficulty mentioned above. Here, we extend the integral representation for the structure factor to many-electron systems treated within the Hartree-Fock method and show how it can be implemented on the basis of standard quantum chemistry software packages. We validate the methodology by considering noble-gas atoms and the CO molecule, for which accurate structure factors exist in the literature. We also present benchmark results for CO2 and for NH3 in the pyramidal and planar geometries.
Ab Initio periodic Hartree-Fock study of group IA cations in ANA-type zeolites
International Nuclear Information System (INIS)
Anchell, J.L.; White, J.C.; Thompson, M.R.; Hess, A.C.
1994-01-01
This study investigates the electronic structure of Group IA cations intercalated into zeolites with the analcime (ANA) framework using ab initio periodic Hartree-Fock theory. The purpose of the study is to gain a better understanding of the role played by electron-donating species in zeolites in general, with specific applications to materials that have been suggested as storage matrices for radioactive materials. The effect of the intercalated species (Na, K, Rb, and Cs) on the electronic structure of the zeolite is presented on the basis of an analysis of the total and projected density of states, Mulliken charges, and charge density differences. The results of those analyses indicate that, relative to a charge neutral atomic state, the Group IA species donate an electron to the zeolite lattice and interact most strongly with the s and p atomic states of oxygen as the species are moved through the lattice. In addition, estimates of the self-diffusion constants of Na, K, Rb, and Cs based upon a one-dimensional diffusion model parameterized from the ab initio total energy data will be presented. 24 refs., 8 figs., 4 tabs
Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model
International Nuclear Information System (INIS)
Erler, Jochen
2011-01-01
Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for α, β-decay and spontaneous fission in a very wide range with proton numbers 86 ≤ Z ≤ 120 and neutron numbers up to N ∼ 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate β-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute β-transition matrix elements and so to provide an estimation of half-lives. (orig.)
Properties of nuclear and neutron matter in a relativistic Hartree-Fock theory
International Nuclear Information System (INIS)
Horowitz, C.J.; Serot, B.D.
1983-01-01
Relativistic-Hartree-Fock (HF) equations are derived for an infinite system of mesons and baryons in the framework of a renormalizable relativistic quantum field theory. The derivation is based on a diagrammatic approach and Dyson's equation for the baryon propagator. The result is a set of coupled, nonlinear integral equations for the baryon self-energy with a self-consistency condition on the single-particle spectrum. The HF equations are solved for nuclear and neutron matter in the Walecka model, which contains neutral scalar and vector mesons. After renormalizing model parameters to reproduce nuclear matter saturation properties, HF results at low to moderate densities are similar to those in the mean-field (Hartree) approximation. Self-consistent exchange corrections to the Hartree equation of state become negligible at high densities. Rho- and pi-meson exchanges are incorporated using a renormalizable gauge-theory model. A chiral transformation of the lagrangian is used to replace the pseudoscalar πN coupling with a pseudovector coupling, for which one-pion exchange is a reasonable first approximation. This transformation maintains the model's renormalizability so that corrections may be evaluated. Pion exchange has a small effect on the HF results of the Walecka model and brings HF results in closer in closer agreement with the mean-field theory. The diagrammatic techniques used here retain the mesonic degrees of freedom and are simple enough to be extended to more refined self-consistent approximations. (orig.)
Exploration of (super-)heavy elements using the Skyrme-Hartree-Fock model
Energy Technology Data Exchange (ETDEWEB)
Erler, Jochen
2011-01-31
Motivated by the steadily increasing number of known nuclei and nuclear properties, theories of nuclear structure are presently a field of intense research. This work concentrates on the self-consistent description of nuclei in terms of the Skyrme-Hartree-Fock (SHF) approach. The extrapolation of nuclear shell structure to the region of super-heavy elements (SHE) using the SHF model, the dependence on different parameterization and the influence of collective correlation will be studied. The general scope of this work are large scale calculation for a global survey of properties of SHE like binding energies, separation energies and decay characteristics and lifetimes. These calculations were done in a collaboration with the theory group of the GSI in Darmstadt and have the aim to develop a database of lifetimes and reaction rates for {alpha}, {beta}-decay and spontaneous fission in a very wide range with proton numbers 86 {<=} Z {<=} 120 and neutron numbers up to N {approx} 260 relevant for the astrophysical r-process. The results of this study for example predictions of a possible islands of very stable nuclei and information of favored decay mode for each nuclei are also applicable in the recent experimental synthesis of exotic SHE. For these calculation a framework to calculate {beta}-decay half-lives within the SHF model has been developed and the existing axial SHF code has been extended to compute {beta}-transition matrix elements and so to provide an estimation of half-lives. (orig.)
International Nuclear Information System (INIS)
Swope, W.C.; Schaefer, H.F. III; Yarkony, D.R.
1980-01-01
The use of Clebsch--Gordan-type coupling coefficients for finite point groups is applied to the problem of constructing symmetrized N-electron wave functions (configurations) for use by the Hartree--Fock SCF and CI methods of determining electronic wave functions for molecular systems. The configurations are eigenfunctions of electronic spin operators, and transform according to a particular irreducible representation of the relevant group of spatial operations which leave the Born--Oppenheimer Hamiltonian invariant. The method proposed for constructing the configurations involves a genealogical coupling procedure. It is particularly useful for studies of molecules which belong to a group which has multiply degenerate irreducible representations. The advantage of the method is that it results in configurations which are real linear combinations of determinants of real symmetry orbitals. This procedure for constructing configurations also allows for the identification of configurations which have no matrix element of the Hamiltonian with a reference configuration. It is therefore possible to construct a Hartree--Fock interacting space of configurations which can speed the convergence of a CI wave function. The coupling method is applied to a study of the ground and two excited electronic states of BH 3 in its D/sub 3h/ geometry. The theoretical approach involved Hartree--Fock SCF calculations followed by single and double substitution CI calculations, both of which employed double-zeta plus polarization quality basis sets
International Nuclear Information System (INIS)
Redon, N.; Meyer, J.; Meyer, M.
1989-01-01
An approximate restoration of the particle number symmetry, a la Lipkin-Nogami, is numerically investigated in the context of Constrained Hartree-Fock plus BCS calculations. Its effect is assessed in a variety of physical situations like potential energy landscapes in transitional nuclei, shape isomerism at low spin and fission barriers of actinide nuclei
Damping of monopole vibrations in time dependent Hartree-Fock theory
International Nuclear Information System (INIS)
Vautherin, D.; Stringari, S.
1979-01-01
Monopole vibrations in oxygen-16 and calcium-40 have been investigated in time-dependent Hartree-Fock theory. The characteristic damping time obtained is tau approximately 1.5x10 -22 sec. This value is in good agreement with the width of the monopole mode calculated in the random phase approximation
Orbital and total atomic momentum expectation values with Roothaan-Hartree-Fock wave functions
International Nuclear Information System (INIS)
De La Vega, J.M.G.; Miguel, B.
1993-01-01
Orbital and total momentum expectation values are computed using the Roothaan-Hartree-Fock wave functions of Clementi and Roetti. These values are calculated analytically and may be used to study the quality of basis sets. Tabulations for ground and excited states of atoms from Z = 2 to Z = 54 are presented. 23 refs., 1 tab
The time-dependent Hartree-Fock equations with Coulomb two-body interaction
International Nuclear Information System (INIS)
Chadam, J.M.; Glassey, R.T.
1975-06-01
The existence and uniqueness of global solutions to the Cauchy problem is proved in the space of ''smooth'' density matrices for the time-dependent Hartree-Fock equations describing the motion of finite Fermi systems interacting via a Coulomb two-body potential [fr
Extension of Hartree-Fock theory including tensor correlation in nuclear matter
Hu, Jinniu; Toki, Hiroshi; Ogawa, Yoko
2013-10-01
We study the properties of nuclear matter in the extension of Hartree-Fock theory including tensor correlation using a realistic nucleon-nucleon (NN) interaction. The nuclear wave function consists of the Hartree-Fock and two-particle-two-hole (2p-2h) states, following the concept of the tensor-optimized shell model (TOSM) for light nuclei. The short range repulsion and strong tensor force of realistic NN interaction provide high momentum components, which are taken into account in a many-body framework by introducing 2p-2h states. Single particle states are determined by the variational principle of the total energy with respect to 2p-2h amplitudes and Hartree-Fock (HF) single-particle states. The resulting differential equation is almost identical with that of Brueckner-Hartree-Fock (BHF) theory by taking two-body scattering terms only. We calculate the equation of state (EOS) of nuclear matter in this framework with the Bonn potential as a realistic NN interaction. We found similar results to BHF theory with slightly repulsive effects in the total energy. The relativistic effect is discussed for the EOSs of nuclear matter in both non-relativistic and relativistic frameworks. The momentum distribution has large components at high momenta due to 2p-2h excitations. We also obtain the EOSs of pure neutron matter, where the tensor effect is small in the iso-vector channel.
Method of renormalization potential for one model of Hartree-Fock-Slater type
Zasorin, Y V
2002-01-01
A new method of the potential renormalization for the quasiclassical model of the Hartree-Fock-Slater real potential is proposed. The method makes it possible to easily construct the wave functions and contrary to the majority od similar methods it does not require the knowledge of the real-type potential
Dirac-Hartree-Fock studies of X-ray transitions in meitnerium
International Nuclear Information System (INIS)
Thierfelder, C.; Schwerdtfeger, P.; Hessberger, F.P.; Hofmann, S.
2008-01-01
The K -shell and L -shell ionizations potentials for 268 109 Mt were calculated at the Dirac-Hartree-Fock level taking into account quantum electrodynamic and finite nuclear-size effects. The K α1 transition energies for different ionization states are accurately predicted and compared with recent experiments in the α -decay of 272 111 Rg. (orig.)
Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme
International Nuclear Information System (INIS)
Theophilou, Iris; Tassi, M.; Thanos, S.
2014-01-01
Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations
An adiabatic time-dependent Hartree-Fock theory of collective motion in finite systems
International Nuclear Information System (INIS)
Baranger, M.; Veneroni, M.
1977-11-01
It is shown how to derive the parameters of a phenomenological collective model from a microscopic theory. The microscopic theory is Hartree-Fock, and one starts from the time-dependent Hartree-Fock equation. To this, the adiabatic approximation is added, and the energy in powers of an adiabatic parameter is expanded, which results in a collective kinetic energy quadratic in the velocities, with coefficients depending on the coordinates, as in the phenomenological models. The adiabatic equations of motion are derived in different ways and their analogy with classical mechanics is stressed. The role of the adiabatic hypothesis and its range of validity, are analyzed in detail. It assumes slow motion, but not small amplitude, and is therefore suitable for large-amplitude collective motion. The RPA is obtained as the limiting case where the amplitude is also small. The translational mass is correctly given and the moment of inertia under rotation is that of Thouless and Valatin
Multiconfiguration hartree-fock theory for pseudorelativistic systems: The time-dependent case
Hajaiej, Hichem
2014-03-01
In [Setting and analysis of the multi-configuration time-dependent Hartree-Fock equations, Arch. Ration. Mech. Anal. 198 (2010) 273-330] the third author has studied in collaboration with Bardos, Catto and Mauser the nonrelativistic multiconfiguration time-dependent Hartree-Fock system of equations arising in the modeling of molecular dynamics. In this paper, we extend the previous work to the case of pseudorelativistic atoms. We show the existence and the uniqueness of global-in-time solution to the underlying system under technical assumptions on the energy of the initial data and the charge of the nucleus. Moreover, we prove that the result can be extended to the case of neutron stars when the number of electrons is less than a critical number N cr. © 2014 World Scientific Publishing Company.
International Nuclear Information System (INIS)
Almbladh, C.-O.; Ekenberg, U.; Pedroza, A.C.
1983-01-01
The authors compare the electron densities and Hartree potentials in the local density and the Hartree-Fock approximations to the corresponding quantities obtained from more accurate correlated wavefunctions. The comparison is made for a number of two-electron atoms, Li, and for Be. The Hartree-Fock approximation is more accurate than the local density approximation within the 1s shell and for the spin polarization in Li, while the local density approximation is slightly better than the Hartree-Fock approximation for charge densities in the 2s shell. The inaccuracy of the Hartree-Fock and local density approximations to the Hartree potential is substantially smaller than the inaccuracy of the local density approximation to the ground-state exchange-correlation potential. (Auth.)
Relativistic description of nuclear systems in the Hartree-Fock approximation
International Nuclear Information System (INIS)
Bouyssy, A.; Mathiot, J.F.; Nguyen Van Giai; Marcos, S.
1986-03-01
The structure of infinite nuclear matter and finite nuclei is studied in the framework of the relativistic Hartree-Fock approximation. A particular attention is paid to the contribution of isovector mesons. (π,p). A satisfactory description of binding energies and densities can be obtained for light as well as heavy nuclei. The spin-orbit splittings are well reproduced. Connections with non-relativistic formulations are also discussed
An introduction to the adiabatic time-dependent Hartree-Fock method
International Nuclear Information System (INIS)
Giannoni, M.J.
1984-05-01
The aim of the adiabatic time-dependent Hartree-Fock method is to investigate the microscopic foundations of the phenomenological collective models. We briefly review the general formulation, which consists in deriving a Bohr-like Hamiltonian from a mean field theory, and discuss the limiting case where only a few collective variables participate to the motion. Some applications to soft nuclei and heavy ion collisions are presented
Coupled Hartree-Fock calculation of {sup 13} C shielding tensors in acetylene clusters
Energy Technology Data Exchange (ETDEWEB)
Craw, John Simon; Nascimento, Marco Antonio Chaer [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica
1992-12-31
The coupled Hartree Fock method has been used to calculate ab-initio carbon magnetic shielding tensors for small clusters of acetylene molecules. The chemical shift increases from the monomer to the dimer and trimer. This is mainly due increased diamagnetism, which is imperfectly cancelled by increased paramagnetism due to loss of axial symmetry. Anisotropic effects are shown to be small in both the dimer the and trimer. (author) 21 refs., 2 tabs.
Positron and electron energy bands in several ionic crystals using restricted Hartree-Fock method
Kunz, A. B.; Waber, J. T.
1981-08-01
Using a restricted Hartree-Fock formalism and suitably localized and symmetrized wave functions, both the positron and electron energy bands were calculated for NaF, MgO and NiO. The lowest positron state at Γ 1 lies above the vacuum level and negative work functions are predicted. Positron annihilation rates were calculated and found to be in good agreement with measured lifetimes.
Hartree-Fock energies of the doubly excited states of the boron isoelectronic sequence
International Nuclear Information System (INIS)
El-Sherbini, T.M.; Mansour, H.M.; Farrag, A.A.; Rahman, A.A.
1985-08-01
Hartree-Fock energies of the 1s 2 2s 2p ns( 4 P), 1s 2 2s 2p np ( 4 P, 4 D) and 1s 2 2s 2p nd ( 4 P, 4 D); n=3-6 states in the boron isoelectronic sequence are reported. The results show a fairly good agreement with the experimental data of Bromander for O IV. (author)
On the solution of the Hartree-Fock-Bogoliubov equations by the conjugate gradient method
International Nuclear Information System (INIS)
Egido, J.L.; Robledo, L.M.
1995-01-01
The conjugate gradient method is formulated in the Hilbert space for density and non-density dependent Hamiltonians. We apply it to the solution of the Hartree-Fock-Bogoliubov equations with constraints. As a numerical application we show calculations with the finite range density dependent Gogny force. The number of iterations required to reach convergence is reduced by a factor of three to four as compared with the standard gradient method. (orig.)
Ground-state properties of axially deformed Sr isotopes in Skyrme-Hartree-Fock-Bogolyubov method
International Nuclear Information System (INIS)
Yilmaz, A.H.; Bayram, T.; Demirci, M.; Engin, B.; Bayram, T.
2010-01-01
Binding energies, the mean-square nuclear radii, neutron radii, quadrupole moments and deformation parameters to axially deformed Strontium isotopes were evaluated using Hartree-Fock-Bogolyubov method. Shape coexistence was also discussed. The results were compared with experimental data and some estimates obtained within some nuclear models. The calculations were performed for SIy4 set of Skyrme forces and for wide range of the neutron numbers of Sr isotopes
Constant resolution of time-dependent Hartree--Fock phase ambiguity
International Nuclear Information System (INIS)
Lichtner, P.C.; Griffin, J.J.; Schultheis, H.; Schultheis, R.; Volkov, A.B.
1978-01-01
The customary time-dependent Hartree--Fock problem is shown to be ambiguous up to an arbitrary function of time additive to H/sub HF/, and, consequently, up to an arbitrary time-dependent phase for the solution, PHI(t). The ''constant'' (H)'' phase is proposed as the best resolution of this ambiguity. It leads to the following attractive features: (a) the time-dependent Hartree--Fock (TDHF) Hamiltonian, H/sub HF/, becomes a quantity whose expectation value is equal to the average energy and, hence, constant in time; (b) eigenstates described exactly by determinants, have time-dependent Hartree--Fock solutions identical with the exact time-dependent solutions; (c) among all possible TDHF solutions this choice minimizes the norm of the quantity (H--i dirac constant delta/delta t) operating on the ket PHI, and guarantees optimal time evolution over an infinitesimal period; (d) this choice corresponds both to the stationary value of the absolute difference between (H) and (i dirac constant delta/delta t) and simultaneously to its absolute minimal value with respect to choice of the time-dependent phase. The source of the ambiguity is discussed. It lies in the time-dependent generalization of the freedom to transform unitarily among the single-particle states of a determinant at the (physically irrelevant for stationary states) cost of altering only a factor of unit magnitude
International Nuclear Information System (INIS)
Seddigi, Z.S.
2004-01-01
We found interesting results regarding some thermodynamical parameters (Delta H, Delta G and Delta S of the MTG Reaction and FTIR Spectra of methanol and dimethylether, using the Hartree-Fock method and Density Functional Theory (DFT) calculations at different computational levels. It is the aim of this paper to highlight these results. The GAUSSIAN 98 program was used to carry out the LCAO-MO-SCF calculations at the following levels: RHF/3-21g, RHF/6-31g and DFT/B3LYP/d95**. Calculations at the restricted Hartree-Fock levels (FHR/3-22 g and RHF/6-31g) were performed since they are expensive as other levels (DFT/B3LYP/d95**. In case of the HF method, working with larger basis set (6-31g) has improved the values slightly, which is as expected. We have noticed that performing calculations at higher levels (DFT/B3LY/D95**) than the Hartree-Fock method does not dramatically improve the situation. Indeed RHF is a reasonable approximation for many single gas phase molecular calculations. HF calculations at relatively small basis sets are adequate. The theoretical vibrational spectra of both methanol and dimethylether were compared with experimental results. (author)
International Nuclear Information System (INIS)
Amusa, A.
1983-03-01
Different Hamiltonians and their corresponding rotationally degenerate intrinsic counterparts are employed in the study of 18 O nucleus under the normal Hartree-Fock, as well as under six other Hartree-Fock type variational calculation schemes. The results are compared and then assessed in the light of their closeness or otherwise to the full 1s-0d basis shell model calculations for this nucleus. The use of these schemes for other shells is also considered. (author)
Energy Technology Data Exchange (ETDEWEB)
Libert, J. [Centre d`Etudes Nucleaires, Bordeaux-1 Univ., 33 Gradignan (France); Girod, M.; Delaroche, J-P.; Berger, J-F.; Romain, P.; Peru, S. [CEA Centre d`Etudes de Bruyeres-le-Chatel, 91 (France)
1997-06-01
The superdeformed bands of the nuclei in the region A = 190 were described by two microscopic approaches using Gogny D1 finite range interaction. The first one consists in building a Bohr Hamiltonian in the framework of Gauss overlap approximation (GOA) of the generator-coordinate method, starting from Hartree-Fock-Bogolyubov solutions under quadrupole constraints. This collective Hamiltonian microscopically determined for five quadrupolar variables is then diagonalized by a projection method on a collective based adapted to the large variety of the deformations to be considered. A special attention was given to the precise definition of the under-barrier collective wavefunctions (for which an original method of solving the collective Schroedinger equation was developed) in order to described correctly the lifetime of the shape isomeric states. The other approach, that of Routhian is based also on the Hartree-Fock-Bogolyubov approximation. The calculations are carried out with and without restoring the broken symmetry associated to the particle numbers (as given by Lipkin-Nogami). The results (excitation energies, moments of inertia, etc...) of the two calculation methods are compared with most recent experimental data. The existence of the superdeformed bands corresponding to vibrational excitations similar to those appearing in {beta} and {gamma} bands is proposed
Hartree-Fock calculation of nuclear binding energy of sodium isotopes
International Nuclear Information System (INIS)
Campi, X.; Flocard, H.
1975-01-01
Mass spectrometer measurements of the neutron rich sodium isotopes show a sudden increase at 31 Na in the values of the two neutron separation energies. The spherical shell model naturally predicts a sudden decrease at 32 Na after the N=20 shell closure. It is proposed that the explanation for this disagreement lies in the fact that sodium isotopes in this mass region are strongly deformed due to the filling of negative parity orbitals from the 1f(7/2) shell. Hartree-Fock calculations are presented in support of this conjecture [fr
Ab initio Hartree-Fock study on surface desorption process in tritium release
International Nuclear Information System (INIS)
Taniguchi, M.; Tanaka, S.
1998-01-01
Dissociative adsorption of hydrogen on Li 2 O (110) surface has been investigated with ab initio Hartree-Fock quantum chemical calculation technique. Heat of adsorption and surface potential energy for H 2 dissociative adsorption were evaluated by calculating the total energy of the system. The calculated results on adsorption heat indicated that H 2 adsorption is endothermic. However, when an oxygen vacancy exists adjacent to the adsorption site, the heat of adsorption became less endothermic and the activation energy required to dissociate the H-H bonding was smaller than that for the terrace site. This is considered to be caused by the excess charge localized near the defect. (orig.)
Hartree-Fock-Bogolubov approximation in the models with general four-fermion interaction
International Nuclear Information System (INIS)
Bogolubov, N.N. Jr.; Soldatov, A.V.
1995-12-01
The foundation of this work was established by the lectures of Prof. N.N. Bogolubov (senior) written in the beginning of 1990. We should like to develop some of his ideas connected with Hartree-Fock-Bogolubov method and to show how this approximation works in connection with general equations for Green's functions with source terms for sufficiently general model Hamiltonian of four-fermion interaction type and how, for example, to get some results of superconductivity theory by means of this method. (author). 5 refs
Time-dependent Hartree-Fock studies of the dynamical fusion threshold
Directory of Open Access Journals (Sweden)
Nakatsukasa Takashi
2012-12-01
Full Text Available A microscopic description of dynamical fusion threshold in heavy ion collisions is performed in the framework of time-dependent Hartree-Fock (TDHF theory using Skyrme energy density functional (EDF. TDHF fusion threshold is in a better agreement with experimental fusion barrier. We find that the onset of extra push lies at the effective fissility 33, which is consistent with the prediction of Swiateckis macroscopic model. The extra push energy in our TDHF simulation is systematically smaller than the prediction in macroscopic model. The important dynamical effects and the way to fit the parameter might be responsible for the different results.
Comparison of the surface friction model with the time-dependent Hartree-Fock method
International Nuclear Information System (INIS)
Froebrich, P.
1984-01-01
A comparison is made between the classical phenomenological surface friction model and a time-dependent Hartree-Fock study by Dhar for the system 208 Pb+ 74 Ge at E/sub lab/(Pb) = 1600 MeV. The general trends for energy loss, mean values for charge and mass, interaction times and energy-angle correlations turn out to be fairly similar in both methods. However, contrary to Dhar, the events close to capture are interpreted as normal deep-inelastic, i.e., not as fast fission processes
Multiconfiguration Dirac-Hartree-Fock calculations of energy levels and radiative rates of Fe VII
Li, Yang; Xu, Xiaokai; Li, Bowen; Jönsson, Per; Chen, Ximeng
2018-06-01
Detailed calculations are performed for 134 fine-structure levels of the 3p63d2, 3p63d4s, 3p53d3 and 3p63d4p configurations in Fe VII using the multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic configuration interaction (RCI) methods. Important electron correlation effects are systematically accounted for through active space (AS) expansions. Our results compare well with experimental measurements, emphasizing the importance of a careful treatment of electron correlation, and provide some missing data in the NIST atomic database. The data obtained are expected to be useful in astrophysical applications, particularly for the research of the solar coronal plasma.
Second-Order Moller-Plesset Perturbation Theory for Molecular Dirac-Hartree-Fock Wave Functions
Dyall, Kenneth G.; Arnold, James O. (Technical Monitor)
1994-01-01
Moller-Plesset perturbation theory is developed to second order for a selection of Kramers restricted Dirac-Hartree-Fock closed and open-shell reference wave functions. The open-shell wave functions considered are limited to those with no more than two electrons in open shells, but include the case of a two-configuration SCF reference. Denominator shifts are included in the style of Davidson's OPT2 method. An implementation which uses unordered integrals with labels is presented, and results are given for a few test cases.
Miranda, R P; Fisher, A J; Stella, L; Horsfield, A P
2011-06-28
The solution of the time-dependent Schrödinger equation for systems of interacting electrons is generally a prohibitive task, for which approximate methods are necessary. Popular approaches, such as the time-dependent Hartree-Fock (TDHF) approximation and time-dependent density functional theory (TDDFT), are essentially single-configurational schemes. TDHF is by construction incapable of fully accounting for the excited character of the electronic states involved in many physical processes of interest; TDDFT, although exact in principle, is limited by the currently available exchange-correlation functionals. On the other hand, multiconfigurational methods, such as the multiconfigurational time-dependent Hartree-Fock (MCTDHF) approach, provide an accurate description of the excited states and can be systematically improved. However, the computational cost becomes prohibitive as the number of degrees of freedom increases, and thus, at present, the MCTDHF method is only practical for few-electron systems. In this work, we propose an alternative approach which effectively establishes a compromise between efficiency and accuracy, by retaining the smallest possible number of configurations that catches the essential features of the electronic wavefunction. Based on a time-dependent variational principle, we derive the MCTDHF working equation for a multiconfigurational expansion with fixed coefficients and specialise to the case of general open-shell states, which are relevant for many physical processes of interest.
Application of the resonating Hartree-Fock random phase approximation to the Lipkin model
International Nuclear Information System (INIS)
Nishiyama, S.; Ishida, K.; Ido, M.
1996-01-01
We have applied the resonating Hartree-Fock (Res-HF) approximation to the exactly solvable Lipkin model by utilizing a newly developed orbital-optimization algorithm. The Res-HF wave function was superposed by two Slater determinants (S-dets) which give two corresponding local energy minima of monopole ''deformations''. The self-consistent Res-HF calculation gives an excellent ground-state correlation energy. There exist excitations due to small vibrational fluctuations of the orbitals and mixing coefficients around their stationary values. They are described by a new approximation called the resonating Hartree-Fock random phase approximation (Res-HF RPA). Matrices of the second-order variation of the Res-HF energy have the same structures as those of the Res-HF RPA's matrices. The quadratic steepest descent of the Res-HF energy in the orbital optimization is considered to include certainly both effects of RPA-type fluctuations up to higher orders and their mode-mode couplings. It is a very important and interesting task to apply the Res-HF RPA to the Lipkin model with the use of the stationary values and to prove the above argument. It turns out that the Res-HF RPA works far better than the usual HF RPA and the renormalized one. We also show some important features of the Res-HF RPA. (orig.)
Kobus, Jacek
2015-02-01
Recently it has been demonstrated that the finite difference Hartree-Fock method can be used to deliver highly accurate values of electric multipole moments together with polarizabilities αz z,Az ,z z , and hyperpolarizabilities βz z z, γz z z,Bz z ,z z , for the ground states of various atomic and diatomic systems. Since these results can be regarded as de facto Hartree-Fock limit values their quality is of the utmost importance. This paper reexamines the use of the finite field method to calculate these electric properties, discusses its accuracy, and presents an updated list of the properties for the following atoms and diatomic molecules: H-, He, Li, Li+,Li2 +,Li-,Be2 + , Be, B+,C2 + , Ne, Mg2 +, Mg, Al+,Si2 + , Ar, K+,Ca2 +,Rb+,Sr2 +,Zr4 +,He2 , Be2,N2,F2,O2 , HeNe, LiH2 +, LiCl, LiBr, BH, CO, FH, NaCl, and KF. The potential energy curves and the dependence of the electric properties on the internuclear distance is also studied for He2,LiH+,Be2 , and HeNe systems.
A correction for the Hartree-Fock density of states for jellium without screening
International Nuclear Information System (INIS)
Blair, Alexander I.; Kroukis, Aristeidis; Gidopoulos, Nikitas I.
2015-01-01
We revisit the Hartree-Fock (HF) calculation for the uniform electron gas, or jellium model, whose predictions—divergent derivative of the energy dispersion relation and vanishing density of states (DOS) at the Fermi level—are in qualitative disagreement with experimental evidence for simple metals. Currently, this qualitative failure is attributed to the lack of screening in the HF equations. Employing Slater’s hyper-Hartree-Fock (HHF) equations, derived variationally, to study the ground state and the excited states of jellium, we find that the divergent derivative of the energy dispersion relation and the zero in the DOS are still present, but shifted from the Fermi wavevector and energy of jellium to the boundary between the set of variationally optimised and unoptimised HHF orbitals. The location of this boundary is not fixed, but it can be chosen to lie at arbitrarily high values of wavevector and energy, well clear from the Fermi level of jellium. We conclude that, rather than the lack of screening in the HF equations, the well-known qualitative failure of the ground-state HF approximation is an artifact of its nonlocal exchange operator. Other similar artifacts of the HF nonlocal exchange operator, not associated with the lack of electronic correlation, are known in the literature
International Nuclear Information System (INIS)
Jiang Minhao; Meng Xujun
2005-01-01
The effect of the free electron background in plasmas is introduced in Hartree-Fock-Slater self-consistent field atomic model to correct the single electron energies for each electron configuration, and to provide accurate atomic data for Boltzmann-Saha equation. In the iteration process chemical potential is adjusted to change the free electron background to satisfy simultaneously the conservation of the free electrons in Saha equation as well as in Hartree-Fock-Slater self-consistent field atomic model. As examples the equations of state of the carbon and aluminum plasmas are calculated to show the applicability of this method. (authors)
Energy Technology Data Exchange (ETDEWEB)
Kato, Tsuyoshi; Ide, Yoshihiro; Yamanouchi, Kaoru [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1, Hongo Bunkyo-ku, Tokyo, 113-0033 (Japan)
2015-12-31
We first calculate the ground-state molecular wave function of 1D model H{sub 2} molecule by solving the coupled equations of motion formulated in the extended multi-configuration time-dependent Hartree-Fock (MCTDHF) method by the imaginary time propagation. From the comparisons with the results obtained by the Born-Huang (BH) expansion method as well as with the exact wave function, we observe that the memory size required in the extended MCTDHF method is about two orders of magnitude smaller than in the BH expansion method to achieve the same accuracy for the total energy. Second, in order to provide a theoretical means to understand dynamical behavior of the wave function, we propose to define effective adiabatic potential functions and compare them with the conventional adiabatic electronic potentials, although the notion of the adiabatic potentials is not used in the extended MCTDHF approach. From the comparison, we conclude that by calculating the effective potentials we may be able to predict the energy differences among electronic states even for a time-dependent system, e.g., time-dependent excitation energies, which would be difficult to be estimated within the BH expansion approach.
Bučinský , Luká š; Malček, Michal; Biskupič, Stanislav; Jayatilaka, Dylan; Bü chel, Gabriel E.; Arion, Vladimir B.
2015-01-01
"Kramers pairs symmetry breaking" is evaluated at the 2-component (2c) Kramers unrestricted and/or general complex Hartree-Fock (GCHF) level of theory, and its analogy with "spin contamination" at the 1-component (1c) unrestricted Hartree-Fock (UHF
Amour, Laurent; Khodja, Mohamed; Nourrigat, Jean
2011-01-01
We study the Wick symbol of a solution of the time dependent Hartree Fock equation, under weaker hypotheses than those needed for the Weyl symbol in the first paper with thesame title. With similar, we prove some kind of Ehrenfest theorem for observables that are not pseudo-differential operators.
Anguiano, M.; Lallena, A. M.; Co', G.; De Donno, V.
2014-02-01
In this work we test the validity of a Hartree-Fock plus Bardeen-Cooper-Schrieffer model in which a finite-range interaction is used in the two steps of the calculation by comparing the results obtained to those found in fully self-consistent Hartree-Fock-Bogoliubov calculations using the same interaction. Specifically, we consider the Gogny-type D1S and D1M forces. We study a wide range of spherical nuclei, far from the stability line, in various regions of the nuclear chart, from oxygen to tin isotopes. We calculate various quantities related to the ground state properties of these nuclei, such as binding energies, radii, charge and density distributions, and elastic electron scattering cross sections. The pairing effects are studied by direct comparison with the Hartree-Fock results. Despite its relative simplicity, in most cases, our model provides results very close to those of the Hartree-Fock-Bogoliubov calculations, and it reproduces the empirical evidence of pairing effects rather well in the nuclei investigated.
Extension of the multiconfiguration Hartree-Fock program for continuum functions
International Nuclear Information System (INIS)
Fischer, C.F.; Saha, H.P.
1984-01-01
The wave function of an outer electron coupled to a core, possibly with correlation included in the core, is similar to a multiconfiguration Hartree-Fock (MCHF) wavefunction, except that the radial function of the electron is a continuum function, and different numerical procedures are required for determining it. Only a single continuum function is allowed, and the orbitals defining the wave function of the core and bound channels are assumed to be fixed. The coefficients in the expansion of the wave function of the core are also fixed and are the result of a bound state calculation for the core. Under these assumptions, the equation for the radial wave function of the electron is solved iteratively. The asymptotic phase shift is evaluated. In order to test the accuracy of the procedure, calculations were performed for the scattering of electrons by neutral hydrogen. Some results of a photo-ionization calculation are compared, and for an electron transition in nitrogen
The contribution of Skyrme Hartree-Fock calculations to the understanding of the shell model
International Nuclear Information System (INIS)
Zamick, L.
1984-01-01
The authors present a detailed comparison of Skyrme Hartree-Fock and the shell model. The H-F calculations are sensitive to the parameters that are chosen. The H-F results justify the use of effective charges in restricted model space calculations by showing that the core contribution can be large. Further, the H-F results roughly justify the use of a constant E2 effective charge, but seem to yield nucleus dependent E4 effective charges. The H-F can yield results for E6 and higher multipoles, which would be zero in s-d model space calculations. On the other side of the coin in H-F the authors can easily consider only the lowest rotational band, whereas in the shell model one can calculate the energies and properties of many more states. In the comparison some apparent problems remain, in particular E4 transitions in the upper half of the s-d shell
Application of the gradient method to Hartree-Fock-Bogoliubov theory
International Nuclear Information System (INIS)
Robledo, L. M.; Bertsch, G. F.
2011-01-01
A computer code is presented for solving the equations of the Hartree-Fock-Bogoliubov (HFB) theory by the gradient method, motivated by the need for efficient and robust codes to calculate the configurations required by extensions of the HFB theory, such as the generator coordinate method. The code is organized with a separation between the parts that are specific to the details of the Hamiltonian and the parts that are generic to the gradient method. This permits total flexibility in choosing the symmetries to be imposed on the HFB solutions. The code solves for both even and odd particle-number ground states, with the choice determined by the input data stream. Application is made to the nuclei in the sd shell using the universal sd-shell interaction B (USDB) shell-model Hamiltonian.
The time dependent Hartree-Fock-theory for collective nuclear motions
International Nuclear Information System (INIS)
Goeke, K.
1976-11-01
The time-dependent Hartree-Fock theory (TDHF) approximately solves the Schroedinger equation by a variational method in the space of the time-dependent Slater determinants. As the TDHF wave function, similar to the exact solution has the property of being determined completely for all times by the nucleon-nucleon interaction and by assuming initial conditions. TDHF is expected to describe collective motion of nuclei with large amplitudes, too. The subject of this paper is to formulate the TDHF theory and its adiabatic limiting case (ATDHF) suited for setting up a collective Schroedinger equation, to investigate the relations with other theories, and to show the applicability for solving practical problems. (orig./WL) [de
Skyrme-Hartree-Fock in the realm of nuclear mean field models
International Nuclear Information System (INIS)
Reinhard, P.G.; Reiss, C.; Maruhn, J.; Bender, M.; Buervenich, T.; Greiner, W.
2000-01-01
We discuss and compare two brands of nuclear mean field models, the Skyrme-Hartree-Fock scheme (SHF) and the relativistic mean field model (RMF). Similarities and differences are worked out on a formal basis and with respect to the models performance in describing nuclear data. The bulk observables of stable nuclei are all described very well. Differences come up when extrapolating to exotic nuclei. The typically larger asymmetry energy in RMF leads to a larger neutron skin. Superheavy nuclei are found to be very sensitive on the single particle levels particularly on the spin orbit splitting. Ground state correlations from collective surface vibrations can have a significant effect on difference observables, as two-nucleon separation energy and two-nucleon shell gap. (author)
International Nuclear Information System (INIS)
Starodubskij, V.E.; Shaginyan, V.R.
1979-01-01
Friar-Negele method is applied to determine the static densities of neutrons and nuclear matter from the fast proton-nuclei elastic scattering data. This model-independent analysis (MIA) has been carried out for 28 Si, sup(32,34)S, sup(40,42,44,48)Ca, 48 Ti, sup(58,60)Ni, 90 Zr, 208 Pb nuclei. The binding energies, rms radii, densities and scattering cross sections of 1 GeV-proton are calculated in the framework of the Hartree-Fock theory (HF) with Skyrme's interaction. The HF and MIA densities and cross sections have been compared to draw a conclusion on the quality of the HF densities. Calculation of the cross sections has included the spin-orbit interaction with parameters taken from the polarization data
Ab-initio Hartree-Fock study of tritium desorption from Li{sub 2}O
Energy Technology Data Exchange (ETDEWEB)
Taniguchi, Masaki; Tanaka, Satoru [Tokyo Univ. (Japan). Faculty of Engineering
1998-03-01
Dissociative adsorption of hydrogen on Li{sub 2}O (110) surface has been investigated with ab-initio Hartree-Fock quantum chemical calculation technique. Heat of adsorption and potential energy surface for H{sub 2} dissociative adsorption was evaluated by calculating the total energy of the system. Calculation results on adsorption heat indicated that H{sub 2} adsorption is endothermic. However, when oxygen vacancy exists adjacent to the adsorption sites, heat of adsorption energy became less endothermic and the activation energy required to dissociate the H-H bonding was smaller than that for the terrace site. This is considered to be caused by the excess charge localized near the defect. (author)
Guidez, Emilie B; Gordon, Mark S
2015-03-12
The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Hartree-Fock (HF-D(EFP)) energies. Overall, DFT-D(EFP) performs similarly to the semiempirical DFT-D corrections for the test cases investigated in this work. HF-D(EFP) tends to underestimate binding energies and overestimate intermolecular equilibrium distances, relative to coupled cluster theory, most likely due to incomplete accounting for electron correlation. Overall, this first-principles dispersion correction yields results that are in good agreement with coupled-cluster calculations at a low computational cost.
On particle emission in the time-dependent Hartree-Fock approximation
International Nuclear Information System (INIS)
Maedler, P.
1984-01-01
Investigations of fast particle emission in the time-dependent Hartree-Fock mean-field approximation (TDHF) have been performed for one-dimensional slab collisions. For a fixed target mass number and incident velocity the total yields of PEP exhibit pronounced srtructures as a function of the pro ectile mass number, which strongly correcate with the binding energy of the last nucleon in the projectnle. This is in explicit disagreement with experiment. The conclusion has been drawn that the Fermi-jet mechanism cannot be responsible for most of the fast particles observed in experiment, even if quantum diffraction is taken into account (as in TDHF). After PEP emission large amplitude density oscillations, which are the only possible modes in the slab geometry, are found to be damped by further particle emission
Adiabatic time-dependent Hartree-Fock theory of collective motion in finite systems
International Nuclear Information System (INIS)
Baranger, M.; Veneroni, M.
1978-01-01
We show how to derive the parameters of a phenomenological collective model from a microscopic theory. The microscopic theory is Hartree-Fock, and we start from the time-dependent Hartree-Fock equation. To this we add the adiabatic approximation, which results in a collective kinetic energy quadratic in the velocities, with coefficients depending on the coordinates, as in the phenomenological models. The crucial step is the decomposition of the single-particle density matrix p in the form exp(i/sub chi/) rho/sub omicron/exp(-i/sub chi/), where rho/sub omicron/ represents a time-even Slater determinant and plays the role of coordinate. Then chi plays the role of momentum, and the adiabatic assumption is that chi is small. The energy is expanded in powers of chi, the zeroth-order being the collective potential energy. The analogy with classical mechanics is stressed and studied. The same adiabatic equations of motion are derived in three different ways (directly, from the Lagrangian, from the Hamiltonian), thus proving the consistency of the theory. The dynamical equation is not necessary for writing the energy or for the subsequent quantization which leads to a Schroedinger equation, but it must be used to check the validity of various approximation schemes, particularly to reduce the problem to a few degrees of freedom. The role of the adiabatic hypothesis, its definition, and range of validity, are analyzed in great detail. It assumes slow motion, but not small amplitude, and is therefore suitable for large-amplitude collective motion. The RPA is obtained as the limiting case where the amplitude is also small. The translational mass is correctly given, and the moment of inertia under rotation is that of Thouless and Valatin. For a quadrupole two-body force, the Baranger-Kumar formalism is recovered. The self-consistency brings additional terms to the Inglis cranking formula. Comparison is also made with generator coordinate methods
A finite difference Hartree-Fock program for atoms and diatomic molecules
Kobus, Jacek
2013-03-01
The newest version of the two-dimensional finite difference Hartree-Fock program for atoms and diatomic molecules is presented. This is an updated and extended version of the program published in this journal in 1996. It can be used to obtain reference, Hartree-Fock limit values of total energies and multipole moments for a wide range of diatomic molecules and their ions in order to calibrate existing and develop new basis sets, calculate (hyper)polarizabilities (αzz, βzzz, γzzzz, Az,zz, Bzz,zz) of atoms, homonuclear and heteronuclear diatomic molecules and their ions via the finite field method, perform DFT-type calculations using LDA or B88 exchange functionals and LYP or VWN correlations ones or the self-consistent multiplicative constant method, perform one-particle calculations with (smooth) Coulomb and Krammers-Henneberger potentials and take account of finite nucleus models. The program is easy to install and compile (tarball+configure+make) and can be used to perform calculations within double- or quadruple-precision arithmetic. Catalogue identifier: ADEB_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADEB_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 2 No. of lines in distributed program, including test data, etc.: 171196 No. of bytes in distributed program, including test data, etc.: 9481802 Distribution format: tar.gz Programming language: Fortran 77, C. Computer: any 32- or 64-bit platform. Operating system: Unix/Linux. RAM: Case dependent, from few MB to many GB Classification: 16.1. Catalogue identifier of previous version: ADEB_v1_0 Journal reference of previous version: Comput. Phys. Comm. 98(1996)346 Does the new version supersede the previous version?: Yes Nature of problem: The program finds virtually exact solutions of the Hartree-Fock and density functional theory type equations for atoms, diatomic molecules and their ions
Bučinský, Lukáš
2015-05-11
"Kramers pairs symmetry breaking" is evaluated at the 2-component (2c) Kramers unrestricted and/or general complex Hartree-Fock (GCHF) level of theory, and its analogy with "spin contamination" at the 1-component (1c) unrestricted Hartree-Fock (UHF) level of theory is emphasized. The GCHF "Kramers pairs symmetry breaking" evaluation is using the square of overlaps between the set of occupied spinorbitals with the projected set of Kramers pairs. In the same fashion, overlaps between α and β orbitals are used in the evaluation of "spin contamination" at the UHF level of theory. In this manner, UHF Š2 expectation value is made formally extended to the GCHF case. The directly evaluated GCHF expectation value of the Š2 operator is considered for completeness. It is found that the 2c GCHF Kramers pairs symmetry breaking has a very similar extent in comparison to the 1c UHF spin contamination. Thus higher excited states contributions to the 1c and 2c unrestricted wave functions of open shell systems have almost the same extent and physical consequences. Moreover, it is formally shown that a single determinant wave function in the restricted open shell Kramers case has the expectation value of K2 operator equal to the negative number of open shell electrons, while the eigenvalue of K2 for the series of simple systems (H, He, He*-triplet, Li and Li*-quartet) are found to be equal to minus the square of the number of open shell electrons. The concept of unpaired electron density is extended to the GCHF regime and compared to UHF and restricted open shell Hartree-Fock spin density. The "collinear" and "noncollinear" analogs of spin density at the GCHF level of theory are considered as well. Spin contamination and/or Kramers pairs symmetry breaking, spin populations and spin densities are considered for H2O+, Cl, HCl+, phenoxyl radical (C6H5O) as well as for Cu, Cu2+, Fe and the [OsCl5(1H-pyrazole)]- anion. The 1c and 2c unpaired electron density representation is found
Variational approach to magnetic moments
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E; Stringari, S; Traini, M [Dipartimento di Matematica e Fisica, Libera Universita di Trento, Italy
1977-11-07
Magnetic moments in nuclei with a spin unsaturated core plus or minus an extra nucleon have been studied using a restricted Hartree-Fock approach. The method yields simple explicit expressions for the deformed ground state and for magnetic moments. Different projection techniques of the HF scheme have been discussed and compared with perturbation theory.
Huntington, Lee M J; Krupička, Martin; Neese, Frank; Izsák, Róbert
2017-11-07
The similarity transformed equation of motion coupled-cluster approach is extended for applications to high-spin open-shell systems, within the unrestricted Hartree-Fock (UHF) formalism. An automatic active space selection scheme has also been implemented such that calculations can be performed in a black-box fashion. It is observed that both the canonical and automatic active space selecting similarity transformed equation of motion (STEOM) approaches perform about as well as the more expensive equation of motion coupled-cluster singles doubles (EOM-CCSD) method for the calculation of the excitation energies of doublet radicals. The automatic active space selecting UHF STEOM approach can therefore be employed as a viable, lower scaling alternative to UHF EOM-CCSD for the calculation of excited states in high-spin open-shell systems.
Huntington, Lee M. J.; Krupička, Martin; Neese, Frank; Izsák, Róbert
2017-11-01
The similarity transformed equation of motion coupled-cluster approach is extended for applications to high-spin open-shell systems, within the unrestricted Hartree-Fock (UHF) formalism. An automatic active space selection scheme has also been implemented such that calculations can be performed in a black-box fashion. It is observed that both the canonical and automatic active space selecting similarity transformed equation of motion (STEOM) approaches perform about as well as the more expensive equation of motion coupled-cluster singles doubles (EOM-CCSD) method for the calculation of the excitation energies of doublet radicals. The automatic active space selecting UHF STEOM approach can therefore be employed as a viable, lower scaling alternative to UHF EOM-CCSD for the calculation of excited states in high-spin open-shell systems.
Adaptive multi-resolution 3D Hartree-Fock-Bogoliubov solver for nuclear structure
Pei, J. C.; Fann, G. I.; Harrison, R. J.; Nazarewicz, W.; Shi, Yue; Thornton, S.
2014-08-01
Background: Complex many-body systems, such as triaxial and reflection-asymmetric nuclei, weakly bound halo states, cluster configurations, nuclear fragments produced in heavy-ion fusion reactions, cold Fermi gases, and pasta phases in neutron star crust, are all characterized by large sizes and complex topologies in which many geometrical symmetries characteristic of ground-state configurations are broken. A tool of choice to study such complex forms of matter is an adaptive multi-resolution wavelet analysis. This method has generated much excitement since it provides a common framework linking many diversified methodologies across different fields, including signal processing, data compression, harmonic analysis and operator theory, fractals, and quantum field theory. Purpose: To describe complex superfluid many-fermion systems, we introduce an adaptive pseudospectral method for solving self-consistent equations of nuclear density functional theory in three dimensions, without symmetry restrictions. Methods: The numerical method is based on the multi-resolution and computational harmonic analysis techniques with a multi-wavelet basis. The application of state-of-the-art parallel programming techniques include sophisticated object-oriented templates which parse the high-level code into distributed parallel tasks with a multi-thread task queue scheduler for each multi-core node. The internode communications are asynchronous. The algorithm is variational and is capable of solving coupled complex-geometric systems of equations adaptively, with functional and boundary constraints, in a finite spatial domain of very large size, limited by existing parallel computer memory. For smooth functions, user-defined finite precision is guaranteed. Results: The new adaptive multi-resolution Hartree-Fock-Bogoliubov (HFB) solver madness-hfb is benchmarked against a two-dimensional coordinate-space solver hfb-ax that is based on the B-spline technique and a three-dimensional solver
Microscopic optical model potential based on Brueckner-Hartree-Fock theory
International Nuclear Information System (INIS)
Li Lulu; Zhao Enguang; Zhou Shangui; Li Zenghua; Zuo Wei; Bonaccorso, Angela; Lonbardo, Umberto
2010-01-01
The optical model is one of the most important models in the study of nuclear reactions. In the optical model, the elastic channel is considered to be dominant and the contributions of all other absorption channels are described by introducing an imaginary potential, Koning and Delaroche obtained empirically the so-called KDR optical potentials based on a best-fitting of massive experimental data on nucleon-nucleus scattering reactions. The volume part is found to be dominant in the real component of the OMP at low energies. Using the Bruckner-Hartree-Fock theory with Bonn B potential plus self consistent three body force, the nucleon-nucleus optical potential is studied in this thesis. In the Bruckner theory, the on-shell self energy, is corresponding to the depth of the volume part of the optical model potential (OMP) for nucleon-nucleus scattering. Using Bruckner-Hartree-Fock theory, the nucleon on-shell self energy is calculated based on Hughenoltz-Van Hove (HVH) theorem. The microscopic optical potentials thus obtained agree well with the volume part of the KDR potentials. Furthermore, the isospin splitting in the volume part of the OMP is also reproduced satisfactorily. The isospin effect in the volume part of the OMP is directly related to the isospin splitting of the effective mass of the nucleon. According to our results, the isospin splitting of neutron to proton effective mass is such that the neutron effective mass increases with isospin, whereas the proton effective mass decreases. The isovector potential U n (E) - U p (E) vanishes at energy E ≈ 200 MeV and then changes sign indicating a possible inversion in the effective mass isospin spitting. We also calculated from the Bruckner theory the imaginary part of the OMP, and the microscopic calculations predict that the isospin splitting exists also in the imaginary OMP whereas the empirical KDR potentials do not show this feature. The shape of the real component of the nucleon-nucleus OMP is
Energy Technology Data Exchange (ETDEWEB)
Lötstedt, Erik, E-mail: lotstedt@chem.s.u-tokyo.ac.jp; Kato, Tsuyoshi; Yamanouchi, Kaoru [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
2016-04-21
An approximate implementation of the multiconfiguration time-dependent Hartree-Fock method is proposed, in which the matrix of configuration-interaction coefficients is decomposed into a product of matrices of smaller dimension. The applicability of this method in which all the configurations are kept in the expansion of the wave function, while the configuration-interaction coefficients are approximately calculated, is discussed by showing the results on three model systems: a one-dimensional model of a beryllium atom, a one-dimensional model of a carbon atom, and a one-dimensional model of a chain of four hydrogen atoms. The time-dependent electronic dynamics induced by a few-cycle, long-wavelength laser pulse is found to be well described at a lower computational cost compared to the standard multiconfiguration time-dependent Hartree-Fock treatment. Drawbacks of the method are also discussed.
Systematic study of even-even nuclei with Hartree-Fock+BCS method using Skyrme SIII force
Energy Technology Data Exchange (ETDEWEB)
Tajima, Naoki; Takahara, Satoshi; Onishi, Naoki [Tokyo Univ. (Japan). Coll. of Arts and Sciences
1997-03-01
We have applied the Hartree-Fock+BCS method with Skyrme SIII force formulated in a three-dimensional Cartesian-mesh representation to even-even nuclei with 2 {<=} Z {<=} 114. We discuss the results concerning the atomic masses, the quadrupole (m=0, 2) and hexadecapole (m=0, 2, 4) deformations, the skin thicknesses, and the halo radii. We also discuss the energy difference between oblate and prolate solutions and the shape difference between protons and neutrons. (author)
Time-dependent Hartree-Fock calculation of the escape width of the giant monopole resonance in 16O
International Nuclear Information System (INIS)
Pacheco, J.M.; Maglione, E.; Broglia, R.A.
1988-01-01
The damping of the giant monopole resonance in 16 O is calculated within the framework of the time-dependent Hartree-Fock approximation. The strength function contains two peaks, centered at around 25 and 33 MeV, with escape widths of ∼11 and ∼2 MeV, associated with the 1p(0p) -1 and 1s(0s) -1 configurations, respectively
Cho, Daeheum; Ko, Kyoung Chul; Ikabata, Yasuhiro; Wakayama, Kazufumi; Yoshikawa, Takeshi; Nakai, Hiromi; Lee, Jin Yong
2015-01-01
The intramolecular magnetic coupling constant (J) of diradical systems linked with five- or six-membered aromatic rings was calculated to obtain the scaling factor (experimental J/calculated J ratio) for various density functional theory (DFT) functionals. Scaling factors of group A (PBE, TPSSh, B3LYP, B97-1, X3LYP, PBE0, and BH&HLYP) and B (M06-L, M06, M06-2X, and M06-HF) were shown to decrease as the amount of Hartree-Fock exact exchange (HFx) increases, in other words, overestimation of calculated J becomes more severe as the HFx increases. We further investigated the effect of HFx fraction of DFT functional on J value, spin contamination, and spin density distributions by comparing the B3LYP analogues containing different amount of HFx. It was revealed that spin contamination and spin densities at each atom increases as the HFx increases. Above all, newly developed BLYP-5 functional, which has 5% of HFx, was found to have the scaling factor of 1.029, indicating that calculated J values are very close to that of experimental values without scaling. BLYP-5 has potential to be utilized for accurate evaluation of intramolecular magnetic coupling constant (J) of diradicals linked by five- or six-membered aromatic ring couplers.
Oscillator strength of partially ionized high-Z atom on Hartree-Fock Slater model
International Nuclear Information System (INIS)
Nakamura, S.; Nishikawa, T.; Takabe, H.; Mima, K.
1991-01-01
The Hartree-Fock Slater (HFS) model has been solved for the partially ionized gold ions generated when an intense laser light is irradiated on a gold foil target. The resultant energy levels are compared with those obtained by a simple screened hydrogenic model with l-splitting effect (SHML). It is shown that the energy levels are poorly model by SHML as the ionization level becomes higher. The resultant wave functions are used to evaluate oscillator strength of important line radiations and compared with those obtained by a simple model using hydrogenic wave functions. Its demonstrated that oscillator strength of the 4p-4d and 4d-4f lines are well modeled by the simple method, while the 4-5 transitions such as 4f-5g, 4d-5f, 4p-5d, and 4f-5p forming the so-called N-band emission are poorly modeled and HFS results less strong line emissions. (author)
Energy Technology Data Exchange (ETDEWEB)
Cho, Daeheum; Ko, Kyoung Chul; Lee, Jin Yong, E-mail: jinylee@skku.edu [Department of Chemistry, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Ikabata, Yasuhiro; Wakayama, Kazufumi; Yoshikawa, Takeshi [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Nakai, Hiromi, E-mail: nakai@waseda.jp [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0075 (Japan); Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520 (Japan)
2015-01-14
The intramolecular magnetic coupling constant (J) of diradical systems linked with five- or six-membered aromatic rings was calculated to obtain the scaling factor (experimental J/calculated J ratio) for various density functional theory (DFT) functionals. Scaling factors of group A (PBE, TPSSh, B3LYP, B97-1, X3LYP, PBE0, and BH and HLYP) and B (M06-L, M06, M06-2X, and M06-HF) were shown to decrease as the amount of Hartree-Fock exact exchange (HFx) increases, in other words, overestimation of calculated J becomes more severe as the HFx increases. We further investigated the effect of HFx fraction of DFT functional on J value, spin contamination, and spin density distributions by comparing the B3LYP analogues containing different amount of HFx. It was revealed that spin contamination and spin densities at each atom increases as the HFx increases. Above all, newly developed BLYP-5 functional, which has 5% of HFx, was found to have the scaling factor of 1.029, indicating that calculated J values are very close to that of experimental values without scaling. BLYP-5 has potential to be utilized for accurate evaluation of intramolecular magnetic coupling constant (J) of diradicals linked by five- or six-membered aromatic ring couplers.
Automatic Differentiation in Quantum Chemistry with Applications to Fully Variational Hartree-Fock.
Tamayo-Mendoza, Teresa; Kreisbeck, Christoph; Lindh, Roland; Aspuru-Guzik, Alán
2018-05-23
Automatic differentiation (AD) is a powerful tool that allows calculating derivatives of implemented algorithms with respect to all of their parameters up to machine precision, without the need to explicitly add any additional functions. Thus, AD has great potential in quantum chemistry, where gradients are omnipresent but also difficult to obtain, and researchers typically spend a considerable amount of time finding suitable analytical forms when implementing derivatives. Here, we demonstrate that AD can be used to compute gradients with respect to any parameter throughout a complete quantum chemistry method. We present DiffiQult , a Hartree-Fock implementation, entirely differentiated with the use of AD tools. DiffiQult is a software package written in plain Python with minimal deviation from standard code which illustrates the capability of AD to save human effort and time in implementations of exact gradients in quantum chemistry. We leverage the obtained gradients to optimize the parameters of one-particle basis sets in the context of the floating Gaussian framework.
On minimal energy Hartree-Fock states for the 2DEG at fractional fillings
International Nuclear Information System (INIS)
Cabo Montes Oca, A. de.
1995-08-01
Approximate minimal energy solutions of the previously discussed general class of Hartree-Fock (HF) states of the 2DEG at 1/3 and 2/3 filling factors are determined. Their selfenergy spectrum is evaluated. Wannier states associated to the filled Bloch states are introduced in a lattice having three flux quanta per cell. They allow to rewrite approximately the ν = 1/3 HF Hamiltonian as sum of three independent tight-binding model Hamiltonians, one describing the dynamics in the band of occupied states and the other ones in the tow bands of excited states. The magnitude of the hopping integral indicates the enhanced role which should have the correlation energy in the present situation with respect to the case of the Yoshioka and Lee second order energy calculation for the lowest energy HF state. Finally, the discussion also suggests the Wannier function, which spreads an electron into a three quanta area, as a physical model for the composite fermion mean field one particle state. (author). 11 refs, 5 figs
Multi-configuration Dirac-Hartree-Fock (MCDHF) calculations for Ni XXV
Singh, Narendra; Aggarwal, Sunny
2018-03-01
We present accurate 165 fine-structure energy levels related to the configurations 1s22s2, 1s22p2, 1s2nƖn‧l‧ (n = 2, n‧ = 2, 3, 4, 5, Ɩ = s,p Ɩ‧ = s, p, d, f, g) of Ni XXV which may be useful ion for astrophysical and fusion plasma. For the calculations of energy levels and radiative rates, we have used the multiconfiguration Dirac-Hartree-Fock (MCDHF) method employed in GRASP2K code. The calculations are carried out in the active space approximation with the inclusion of the Breit interaction, the finite nuclear size effect, and quantum electrodynamic corrections. The transition wavelengths, transition probabilities, line strengths, and absorption oscillator strengths are reported for electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), magnetic quadrupole (M2) transitions from the ground state. We have compared our calculated results with available theoretical and experimental data and good agreement is achieved. We predict new energy levels, oscillator strengths, line strengths and transition probabilities, where no other experimental or theoretical results are available. The present complete set of results should be of great help in line identification and the interpretation of spectra, as well as in the modelling and diagnostics of astrophysical and fusion plasmas.
Study of superdeformation at zero spin with Skyrme-Hartree-Fock method
Energy Technology Data Exchange (ETDEWEB)
Takahara, S; Tajima, N; Onishi, N [Tokyo Univ. (Japan)
1998-03-01
Superdeformed (SD) bands have been studied extensively both experimentally and theoretically in the last decade. Since the first observation in {sup 152}Dy in 1986, SD bands have been found in four mass regions, i.e., A {approx} 80, 130, 150 and 190. While these SD bands have been observed only at high spins so far, they may also be present at zero spin like fission isomers in actinide nuclei: The familiar generic argument on the strong shell effect at axis ratio 2:1 does not assume rotations. If non-fissile SD isomers exist at zero spin, they may be utilized to develop new experimental methods to study exotic states, in a similar manner as short-lived high-spin isomers are planned to be utilized as projectiles of fusion reactions in order to populate very high-spin near-yrast states. They will also be useful to test theoretical models whether the models can describe correctly the large deformations of rare-earth nuclei without further complications due to rotations. In this report, we employ the Skyrme-Hartree-Fock method to study the SD states at zero spin. First, we compare various Skyrme force parameter sets to test whether they can reproduce the extrapolated excitation energy of the SD band head of {sup 194}Hg. Second, we systematically search large-deformation solutions with the SkM{sup *} force. The feature of our calculations is that the single-particle wavefunctions are expressed in a three-dimensional-Cartesian-mesh representation. This representation enables one to obtain solutions of various shapes (including SD) without preparing a basis specific to each shape. Solving the mean-field equations in this representation requires, however, a large amount of computation which can be accomplished only with present supercomputers. (author)
Brandenburg, Jan Gerit; Grimme, Stefan
2014-01-01
We present and evaluate dispersion corrected Hartree-Fock (HF) and Density Functional Theory (DFT) based quantum chemical methods for organic crystal structure prediction. The necessity of correcting for missing long-range electron correlation, also known as van der Waals (vdW) interaction, is pointed out and some methodological issues such as inclusion of three-body dispersion terms are discussed. One of the most efficient and widely used methods is the semi-classical dispersion correction D3. Its applicability for the calculation of sublimation energies is investigated for the benchmark set X23 consisting of 23 small organic crystals. For PBE-D3 the mean absolute deviation (MAD) is below the estimated experimental uncertainty of 1.3 kcal/mol. For two larger π-systems, the equilibrium crystal geometry is investigated and very good agreement with experimental data is found. Since these calculations are carried out with huge plane-wave basis sets they are rather time consuming and routinely applicable only to systems with less than about 200 atoms in the unit cell. Aiming at crystal structure prediction, which involves screening of many structures, a pre-sorting with faster methods is mandatory. Small, atom-centered basis sets can speed up the computation significantly but they suffer greatly from basis set errors. We present the recently developed geometrical counterpoise correction gCP. It is a fast semi-empirical method which corrects for most of the inter- and intramolecular basis set superposition error. For HF calculations with nearly minimal basis sets, we additionally correct for short-range basis incompleteness. We combine all three terms in the HF-3c denoted scheme which performs very well for the X23 sublimation energies with an MAD of only 1.5 kcal/mol, which is close to the huge basis set DFT-D3 result.
Symbolic computation of the Hartree-Fock energy from a chiral EFT three-nucleon interaction at N2LO
International Nuclear Information System (INIS)
Gebremariam, B.; Bogner, S.K.; Duguet, T.
2010-01-01
We present the first of a two-part Mathematica notebook collection that implements a symbolic approach for the application of the density matrix expansion (DME) to the Hartree-Fock (HF) energy from a chiral effective field theory (EFT) three-nucleon interaction at N 2 LO. The final output from the notebooks is a Skyrme-like energy density functional that provides a quasi-local approximation to the non-local HF energy. In this paper, we discuss the derivation of the HF energy and its simplification in terms of the scalar/vector-isoscalar/isovector parts of the one-body density matrix. Furthermore, a set of steps is described and illustrated on how to extend the approach to other three-nucleon interactions. Program summary: Program title: SymbHFNNN; Catalogue identifier: AEGC v 1 0 ; Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEGC_v1_0.html; Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland; Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html; No. of lines in distributed program, including test data, etc.: 96 666; No. of bytes in distributed program, including test data, etc.: 378 083; Distribution format: tar.gz; Programming language: Mathematica 7.1; Computer: Any computer running Mathematica 6.0 and later versions; Operating system: Windows Xp, Linux/Unix; RAM: 256 Mb; Classification: 5, 17.16, 17.22; Nature of problem: The calculation of the HF energy from the chiral EFT three-nucleon interaction at N 2 LO involves tremendous spin-isospin algebra. The problem is compounded by the need to eventually obtain a quasi-local approximation to the HF energy, which requires the HF energy to be expressed in terms of scalar/vector-isoscalar/isovector parts of the one-body density matrix. The Mathematica notebooks discussed in this paper solve the latter issue. Solution method: The HF energy from the chiral EFT three-nucleon interaction at N 2 LO is cast into a form suitable for an automatic
International Nuclear Information System (INIS)
Ayikoglu, A.
2008-01-01
The molecular structure, vibrational frequencies and corresponding vibrational assignments of tetrafluoro isophthalonitrile (TFPN) in the ground state have been calculated using the Hartree-Fock (HF) and density functional methods (B3LYP) with 6-311++G (d, p) basis set. The calculations were utilized in the CS symmetry of TFPN. The obtained vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) were seen to be in good agreement with the experimental data. The comparison of the observed and calculated results showed that the B3LYP method is superior to the HF method for both the vibrational frequencies and geometric parameters
Energy Technology Data Exchange (ETDEWEB)
Goodman, A L [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)
1976-07-12
The Hartree-Fock-Bogolyubov cranking equations are solved for /sup 168/ /sup 170/Yb and /sup 174/Hf. Deformation and pairing properties are both obtained with a G-matrix derived from the Reid soft-core potential. The high spin anomalies are attributed to the disappearance of the neutron pair gap in /sup 168/Yb, the realignment of an isub(13/2) neutron pair in /sup 170/Yb, and a combination of these two mechanisms in /sup 174/Hf. Two bands intersecting at high spin are found for /sup 174/Hf.
Physically asymptotic Hartree-Fock stationary-phase approximant to the many-body S-matrix
International Nuclear Information System (INIS)
Griffin, J.J.; Dworzecka, M.
1982-01-01
The Asymptotic Hartree-Fock Approximant replaces the physically non-asymptotic (and dynamically nontrivial) external translation of the FISP result with the asymptotic and dynamically trivial translational evolution of Dirac-TDHF by adding an explicit restriction upon the acceptable channel states. It is therefore preferable under the principle of commensurability, which judges the expected output of physical descriptions in terms of the physical assumptions they incorporate. Further insight into the relationship between the TDSHF and FISP methods will reward careful comparison of the respective expressions, in specific cases
International Nuclear Information System (INIS)
Schunck, Nicolas F.; McDonnell, J.; Sheikh, J.A.; Staszczak, A.; Stoitsov, Mario; Dobaczewski, J.; Toivanen, P.
2012-01-01
We describe the new version (v2.49t) of the code HFODD which solves the nuclear Skyrme Hartree-Fock (HF) or Skyrme Hartree-Fock-Bogolyubov (HFB) problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we have implemented the following physics features: (i) the isospin mixing and projection, (ii) the finite temperature formalism for the HFB and HF+BCS methods, (iii) the Lipkin translational energy correction method, (iv) the calculation of the shell correction. A number of specific numerical methods have also been implemented in order to deal with large-scale multi-constraint calculations and hardware limitations: (i) the two-basis method for the HFB method, (ii) the Augmented Lagrangian Method (ALM) for multi-constraint calculations, (iii) the linear constraint method based on the approximation of the RPA matrix for multi-constraint calculations, (iv) an interface with the axial and parity-conserving Skyrme-HFB code HFBTHO, (v) the mixing of the HF or HFB matrix elements instead of the HF fields. Special care has been paid to using the code on massively parallel leadership class computers. For this purpose, the following features are now available with this version: (i) the Message Passing Interface (MPI) framework, (ii) scalable input data routines, (iii) multi-threading via OpenMP pragmas, (iv) parallel diagonalization of the HFB matrix in the simplex breaking case using the ScaLAPACK library. Finally, several little significant errors of the previous published version were corrected.
Lee, Hyun-Jung; Kim, Ki-Seok
2018-04-01
We investigate the role of Coulomb interaction in the multifractality of Anderson metal-insulator transition, where the Coulomb interaction is treated within the Hartree-Fock approximation, but disorder effects are taken into account exactly. An innovative technical aspect in our simulation is to utilize the Ewald-sum technique, which allows us to introduce the long-range nature of the Coulomb interaction into Hartree-Fock self-consistent equations of order parameters more accurately. This numerical simulation reproduces the Altshuler-Aronov correction in a metallic state and the Efros-Shklovskii pseudogap in an insulating phase, where the density of states ρ (ω ) is evaluated in three dimensions. Approaching the quantum critical point of a metal-insulator transition from either the metallic or insulting phase, we find that the density of states is given by ρ (ω ) ˜|ω| 1 /2 , which determines one critical exponent of the McMillan-Shklovskii scaling theory. Our main result is to evaluate the eigenfunction multifractal scaling exponent αq, given by the Legendre transformation of the fractal dimension τq, which characterizes the scaling behavior of the inverse participation ratio with respect to the system size L . Our multifractal analysis leads us to identify two kinds of mobility edges, one of which occurs near the Fermi energy and the other of which appears at a high energy, where the density of states at the Fermi energy shows the Coulomb-gap feature. We observe that the multifractal exponent at the high-energy mobility edge remains to be almost identical to that of the Anderson localization transition in the absence of Coulomb interactions. On the other hand, we find that the multifractal exponent near the Fermi energy is more enhanced than that at the high-energy mobility edge, suspected to result from interaction effects. However, both the multifractal exponents do not change even if the strength of the Coulomb interaction varies. We also show that the
International Nuclear Information System (INIS)
Lindner, J.
1992-09-01
In this thesis in the framework of our model of the field-strength dependent coupling the properties of infinitely extended, homogeneous, static, spin- and isospin-saturated nuclear matter are studied. Thereby we use the Hartree-Mean-Field and the Hartree-Fock approximation, whereby the influence of the antiparticle states in the Fermi sea is neglected. In chapter 2 the Lagrangian density basing to our model is fixed. Starting from the Walecka model we modify in the Lagrangian density the Linear coupling of the scalar field to the scalar density as follows g S φanti ψψ→g S f(φ) anti ψψ. In chapter 3 we fix three different functions f(φ). For these three cases and for the Walecka model with f(φ)=φ nuclear-matter calculations are performed. In chapter 4 for the Hartree-Fock calculations, but also very especially regarding the molecular-dynamics calculations, the properties of the Dirac spinors in the plane-wave representation are intensively studied. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Small, David W.; Sundstrom, Eric J.; Head-Gordon, Martin [Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2015-01-14
Restricted Hartree Fock using complex-valued orbitals (cRHF) is studied. We introduce an orbital pairing theorem, with which we obtain a concise connection between cRHF and real-valued RHF, and use it to uncover the close relationship between cRHF, unrestricted Hartree Fock, and generalized valence bond perfect pairing. This enables an intuition for cRHF, contrasting with the generally unintuitive nature of complex orbitals. We also describe an efficient computer implementation of cRHF and its corresponding stability analysis. By applying cRHF to the Be + H{sub 2} insertion reaction, a Woodward-Hoffmann violating reaction, and a symmetry-driven conical intersection, we demonstrate in genuine molecular systems that cRHF is capable of removing certain potential energy surface singularities that plague real-valued RHF and related methods. This complements earlier work that showed this capability in a model system. We also describe how cRHF is the preferred RHF method for certain radicaloid systems like singlet oxygen and antiaromatic molecules. For singlet O{sub 2}, we show that standard methods fail even at the equilibrium geometry. An implication of this work is that, regardless of their individual efficacies, cRHF solutions to the HF equations are fairly commonplace.
Perger, W. F.; Das, B. P.
1987-01-01
The parity-nonconserving electric-dipole-transition amplitudes for the 6s1/2-7s1/2 transition in cesium and the 6p1/2-7p1/2 transition in thallium have been calculated by the Dirac-Hartree-Fock method. The effects of using different Dirac-Hartree-Fock atomic core potentials are examined and the transition amplitudes for both the length and velocity gauges are given. It is found that the parity-nonconserving transition amplitudes exhibit a greater dependence on the starting potential for thallium than for cesium.
Rodríguez-Sánchez, Jose Luis; David, Jean-Christophe; Mancusi, Davide; Boudard, Alain; Cugnon, Joseph; Leray, Sylvie
2017-11-01
The prediction of one-nucleon-removal cross sections by the Liège intranuclear-cascade model has been improved using a refined description of the matter and energy densities in the nuclear surface. Hartree-Fock-Bogoliubov calculations with the Skyrme interaction are used to obtain a more realistic description of the radial-density distributions of protons and neutrons, as well as the excitation-energy uncorrelation at the nuclear surface due to quantum effects and short-range correlations. The results are compared with experimental data covering a large range of nuclei, from carbon to uranium, and projectile kinetic energies. We find that the new approach is in good agreement with experimental data of one-nucleon-removal cross sections covering a broad range in nuclei and energies. The new ingredients also improve the description of total reaction cross sections induced by protons at low energies, the production cross sections of heaviest residues close to the projectile, and the triple-differential cross sections for one-proton removal. However, other observables such as quadruple-differential cross sections of coincident protons do not present any sizable sensitivity to the new approach. Finally, the model is also tested for light-ion-induced reactions. It is shown that the new parameters can give a reasonable description of the nucleus-nucleus total reaction cross sections at high energies.
International Nuclear Information System (INIS)
Villars, F.
1975-01-01
The objective of the work is to draw attention to the essential equivalence of the two apparently quite distinct ways of describing nuclear collective dyanmics, the adiabatic time-dependent Hartree-Fock method (ADTHF) on the one hand, and the Generator Coordinate (GC) method on the other hand. To demonstrate this relation, an analysis of the simplest case, in which collective motion is described by a single collective para- meter q(t) is presented. In the ATDHF approach, two self-consistency conditions are obtained; the resultant expressions for the collective potential and kinetic energies represent a special case of the more general results of Baranger and Veneroni. In the G.C. approach to the same system (with the same collective parameter q), the narrow overlap approximation must be made, as the counterpart of the adiabatic approximation in the TDHF method. In its conventional form, the G.C. method leads to a different expression for the collective kinetic energy. It is shown however, that a simple generalization of the G.C.-wave function leads to corrections determined by a variational principle. In leading order, the corrected expression for the collective kinetic energy is identical with the TDHF result In both cases, the collective inertia is determined by a self-consistent cranking formula
Energy Technology Data Exchange (ETDEWEB)
Kilin, V.A. [Tomsk Polytechnic University, Tomsk (Russian Federation); Lazarev, D.V.; Lazarev, Dm.A.; Zelichenko, V.M. [Tomsk Pedagogic University, Tomsk (Russian Federation); Amusia, M. Ya. [A.F. Ioffe Physico-Technical Institute, St. Petersburg (Russian Federation); Schartner, K.-H. [I Physikalisches Institut, Justus-Liebig-Universitaet, Giessen (Germany); Ehresmann, A.; Schmoranzer, H. [Fachbereich Physik, Universitaet Kaiserslautern, Kaiserslautern (Germany)
2001-10-28
The approach of a parametric V{sup (N-q)} Hartree-Fock potential with fractional q is developed and applied for the first time for the calculation of the double photoionization cross sections of Ne. A minimum of the squared difference between the length-form and velocity-form cross sections is used as a criterion for calculating the values of q. It is found that the minimization procedure leads to a practically exact equality of the length-form and velocity-form cross sections for the Ne III 2s{sup 2}2p{sup 4}[{sup 3}P,{sup 1}D,{sup 1}S], 2s{sup 1}2p{sup 5}[{sup 3}P,{sup 1}P] and 2s{sup 0}2p{sup 6}[{sup 1}S] states in the exciting-photon energy region from the double-ionization threshold up to 325 eV, if q is considered as a function of the exciting-photon energy. The calculated V{sup (N-q)} cross sections are in better agreement with the experimental data than those for the V{sup (N-1)} and V{sup (N-2)} potentials. (author)
King, Andrew W; Baskerville, Adam L; Cox, Hazel
2018-03-13
An implementation of the Hartree-Fock (HF) method using a Laguerre-based wave function is described and used to accurately study the ground state of two-electron atoms in the fixed nucleus approximation, and by comparison with fully correlated (FC) energies, used to determine accurate electron correlation energies. A variational parameter A is included in the wave function and is shown to rapidly increase the convergence of the energy. The one-electron integrals are solved by series solution and an analytical form is found for the two-electron integrals. This methodology is used to produce accurate wave functions, energies and expectation values for the helium isoelectronic sequence, including at low nuclear charge just prior to electron detachment. Additionally, the critical nuclear charge for binding two electrons within the HF approach is calculated and determined to be Z HF C =1.031 177 528.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).
International Nuclear Information System (INIS)
Sadlej, A.J.
1980-01-01
The problem of the most efficient perturbation calculation of the correlation contributions to atomic and molecular properties is discussed. The method which is based on the coupled Hartree-Fock (CHF) perturbation theory appears to be the most promising one. The CHF-based perturbation theory of correlation effects is applied to the calculation of the second-order correlation contributions to the electric dipole polarizabilities of He, Be and Ne. The numerical approach employed in this paper consists in computing first the electric-field-dependent SCF functions. Then, the field dependent second-order correlation energy is calculated. The electric dipole polarizabilities, accurate through the second-order in correlation, are obtained via the numerical differentiation of the field-dependent energies with respect to the external electric field strength. In order to avoid the use of very large basis sets the so-called electric-field-variant (EFV) orbitals are employed in the present study. The CHF results obtained in this paper are of the same accuracy as the best literature data. In addition of the second-order correlation correction the final values of the electric dipole polarizability differ from the accurate or experimental results by less than a few per cent. (author)
Application of the RPA method based on the cranked Hartree-Fock-Bogolyubov model in 168Er and 158Dy
International Nuclear Information System (INIS)
Kvasil, J.; Khariev, M.M.; Cwiok, S.; Mikhajlov, I.N.; Khoriev, B.
1984-01-01
The Random Phase Approximation (RPA) based on the Cranked Hartree-Fock-Bogolyubov (CHFB) model is used for the study of low-lying nuclear states near the yrast line in 158 Dy and 168 Er. The relation of the spurious unphysical states connected with the nucleus centre of mass rotational motion to the solutions of RPA equations of motion is cleared up. The calculated level energies and reduced probabilities B(E2) are compared with experimental ones. The dependence of the residual interaction strength constants and the nucleus moment of inertia on the angular momentum is discussed. The experimental characteristics of low-lying states up to approx. 2 MeV are reproduced by the CHFB+RPA model. (author)
International Nuclear Information System (INIS)
West, Aaron C.; Schmidt, Michael W.; Gordon, Mark S.; Ruedenberg, Klaus
2013-01-01
Through a basis-set-independent web of localizing orbital-transformations, the electronic wave function of a molecule is expressed in terms of a set of orbitals that reveal the atomic structure and the bonding pattern of a molecule. The analysis is based on resolving the valence orbital space in terms of an internal space, which has minimal basis set dimensions, and an external space. In the internal space, oriented quasi-atomic orbitals and split-localized molecular orbitals are determined by new, fast localization methods. The density matrix between the oriented quasi-atomic orbitals as well as the locations of the split-localized orbitals exhibit atomic populations and inter-atomic bonding patterns. A correlation-adapted quasi-atomic basis is determined in the external orbital space. The general formulations are specified in detail for Hartree-Fock wave functions. Applications to specific molecules exemplify the general scheme
Sert, Y.; Ucun, F.
2013-08-01
In the present work, the theoretical vibrational spectra of p-, m- and o-nitrobenzonitrile molecules have been analyzed. The harmonic vibrational frequencies and geometric parameters (bond lengths and bond angles) of these molecules have been calculated using ab initio Hartree-Fock and density functional theory methods with 6-311++G(d,p) basis set by Gaussian 03 W, for the first time. Assignments of the vibrational frequencies have been performed by potential energy distribution by using VEDA 4 program. The optimized geometric parameters and harmonic vibrational frequencies have been compared with the corresponding experimental data and seen to be in a good agreement with each other. Also, the highest occupied molecular orbital and lowest unoccupied molecular orbital energies have been obtained.
Energy Technology Data Exchange (ETDEWEB)
Lata, K. Ramani [State University of New York at Albany, Department of Physics (United States); Sahoo, N. [University of Texas M.D. Anderson Cancer Center, Department of Radiation Physics (United States); Dubey, Archana [University of Central Florida, Department of Physics (United States); Scheicher, R. H. [Uppsala University, Condensed Matter Theory Group, Department of Physics and Materials Science (Sweden); Badu, S. R.; Pink, R. H.; Mahato, Dip N. [State University of New York at Albany, Department of Physics (United States); Schulte, A. F.; Saha, H. P. [University of Central Florida, Department of Physics (United States); Maharjan, N. B. [State University of New York at Albany, Department of Physics (United States); Chow, Lee [University of Central Florida, Department of Physics (United States); Das, T. P., E-mail: tpd56@albany.edu [State University of New York at Albany, Department of Physics (United States)
2008-01-15
The electronic structure of the heme unit of deoxyhemoglobin including the proximal imidazole has been studied using the first-principles Hartree-Fock procedure. Our results for the {sup 57m}Fe isomer shift and asymmetry parameter are in very good agreement with the values obtained from Moessbauer spectroscopy measurements. The {sup 57m}Fe nuclear quadrupole coupling constant is smaller than the experimental result and possible ways to improve the agreement in the future are discussed. Improved analysis of the Moessbauer data, removing some approximations made for deriving the magnetic hyperfine tensor for the {sup 57m}Fe nucleus, is suggested to allow quantitative comparison with our results in the future.
Rayka, Milad; Goli, Mohammad; Shahbazian, Shant
2018-02-07
An effective set of Hartree-Fock (HF) equations are derived for electrons of muonic systems, i.e., molecules containing a positively charged muon, conceiving the muon as a quantum oscillator, which are completely equivalent to the usual two-component HF equations used to derive stationary states of the muonic molecules. In these effective equations, a non-Coulombic potential is added to the orthodox coulomb and exchange potential energy terms, which describes the interaction of the muon and the electrons effectively and is optimized during the self-consistent field cycles. While in the two-component HF equations a muon is treated as a quantum particle, in the effective HF equations it is absorbed into the effective potential and practically transformed into an effective potential field experienced by electrons. The explicit form of the effective potential depends on the nature of muon's vibrations and is derivable from the basis set used to expand the muonic spatial orbital. The resulting effective Hartree-Fock equations are implemented computationally and used successfully, as a proof of concept, in a series of muonic molecules containing all atoms from the second and third rows of the Periodic Table. To solve the algebraic version of the equations muon-specific Gaussian basis sets are designed for both muon and surrounding electrons and it is demonstrated that the optimized exponents are quite distinct from those derived for the hydrogen isotopes. The developed effective HF theory is quite general and in principle can be used for any muonic system while it is the starting point for a general effective electronic structure theory that incorporates various types of quantum correlations into the muonic systems beyond the HF equations.
International Nuclear Information System (INIS)
Kohno, M.
1983-01-01
We report fully consistent calculations of the longitudinal and transverse response functions of the inclusive quasi-elastic electron scattering on 12 C in the Hartree-Fock approximation. The distorted wave for the outgoing nucleon is constructed from the same non-local Hartree-Fock field as in the ground-state description. Thus the orthogonality and Pauli principle requirements are naturally satisfied. The theoretical prediction, based on the standard density-dependent effective interaction (GO force), shows a good correspondence to the experimental data. Since the calculated response functions automatically satisfy the relevant sum rule, this work illuminates the well-known puzzle concerning the longitudinal part, which remains to be solved. We study the energy-weighted sum rules and discuss effects beyond the mean-field approximation. Meson-exchange-current contributions to the transverse response function are also estimated and found to be small due to cancellations among them. (orig.)
International Nuclear Information System (INIS)
Cabo Monte Oca, A. de.
1994-07-01
Analytic expressions for order parameters are given for the previously introduced general class of Hartree Fock states at arbitrary filling factors ν=p/q for odd q values. The order parameters are expressed as sums of magnetic translations eigenvalues over the filled single electron states. Simple summation formulae for the band spectra in terms of the same eigenvalues are also presented. The energy per particle at ν=1/3 is calculated for various states differing in the way of filling of the 1/3 of the orbitals. The calculated energies are not competing with the usual CDW results. However the high degree of electron overlapping allows for the next corrections to modify this situation. The discussion suggests these Hartree-Fock Slater determinants as interesting alternatives for the Tao-Thouless parent states which may correct their anomalous symmetry and correlation functions properties. (author). 28 refs
Chong, Jacky Jia Wei
2018-04-01
We prove the global well-posedness of the time-dependent Hartree-Fock-Bogoliubov (TDHFB) equations in R^{1+1} with two-body interaction potential of the form N^{-1}v_N(x) = N^{β -1} v(N^β x) where v≥0 is a sufficiently regular radial function, i.e., v \\in L^1(R)\\cap C^∞ (R) . In particular, using methods of dispersive PDEs similar to the ones used in Grillakis and Machedon (Commun Partial Differ Equ 42:24-67, 2017), we are able to show for any scaling parameter β >0 the TDHFB equations are globally well-posed in some Strichartz-type spaces independent of N, cf. (Bach et al. in The time-dependent Hartree-Fock-Bogoliubov equations for Bosons, 2016. arXiv:1602.05171).
International Nuclear Information System (INIS)
Hu, J.; Toki, H.; Wen, W.; Shen, H.
2010-01-01
The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size (Λ∝1.0 -2.0 GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ-meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ-meson energies in the relativistic Hartree-Fock approximation for nuclear matter. (orig.)
Hu, J.; Toki, H.; Wen, W.; Shen, H.
2010-03-01
The role of the form factor and short-range correlation in nuclear matter is studied within the relativistic Hartree-Fock approximation. We take, first, the mean-field approximation for meson fields and obtain the fluctuation terms of mesons to be used for the Fock energies. We introduce form factors in the meson-nucleon coupling vertices to take into account the finite-size effect of the nucleon. We use further the unitary correlation operator method for the treatment of the short-range correlation. The form factors of the size ( Λ ˜ 1.0 -2.0GeV) of the nucleon-nucleon interaction cut down largely the contribution of the ρ -meson in the Fock term. The short-range correlation effect is not large but has a significant effect on the pion and ρ -meson energies in the relativistic Hartree-Fock approximation for nuclear matter.
Liang, Wenkel; Isborn, Christine M.; Li, Xiaosong
2009-11-01
The calculation of doubly excited states is one of the major problems plaguing the modern day excited state workhorse methodology of linear response time dependent Hartree-Fock (TDHF) and density function theory (TDDFT). We have previously shown that the use of a resonantly tuned field within real-time TDHF and TDDFT is able to simultaneously excite both the α and β electrons to achieve the two-electron excited states of minimal basis H2 and HeH+ [C. M. Isborn and X. Li, J. Chem. Phys. 129, 204107 (2008)]. We now extend this method to many electron systems with the use of our Car-Parrinello density matrix search (CP-DMS) with a first-principles fictitious mass method for wave function optimization [X. Li, C. L. Moss, W. Liang, and Y. Feng, J. Chem. Phys. 130, 234115 (2009)]. Real-time TDHF/TDDFT is used during the application of the laser field perturbation, driving the electron density toward the doubly excited state. The CP-DMS method then converges the density to the nearest stationary state. We present these stationary state doubly excited state energies and properties at the HF and DFT levels for H2, HeH+, lithium hydride, ethylene, and butadiene.
Wang, Hao
2014-07-01
The metal-insulator transition of VO2 so far has evaded an accurate description by density functional theory. The screened hybrid functional of Heyd, Scuseria and Ernzerhof leads to reasonable solutions for both the low-temperature monoclinic and high-temperature rutile phases only if spin polarization is excluded from the calculations. We explore whether a satisfactory agreement with experiment can be achieved by tuning the fraction of Hartree Fock exchange (α) in the density functional. It is found that two branches of locally stable solutions exist for the rutile phase for 12.5%≤α≤20%. One is metallic and has the correct stability as compared to the monoclinic phase, the other is insulating with lower energy than the metallic branch. We discuss these observations based on the V 3d orbital occupations and conclude that α=10% is the best possible choice for spin-polarized VO2 calculations. © 2014 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Cinakli, S.; Sert, Y.; Boeyuekata, M.; Ucun, F.
2010-01-01
The vibrational spectra of benzaldehyde and its derivatives have been studied earlier. The substitution of a functional group changes the spectra markedly. Recent spectroscopic studies of the benzaldehyde and their derivatives have been motivated because the vibrational spectra are very useful for understanding of specific biological process and in the analysis of relatively complex systems. The optimized molecular structure, vibrational frequencies and corresponding vibrational assignments, the total energy calculations, relative energies, the mean vibrational deviations of the two planar O-cis and O-trans roomers of 5-Hydroxy 2-nitrobenzaldehydes have been calculated using ab initio Hartree Fock (HF) and Density Functional Theory (B3LYP) with 6-311++G(d,p) basis set. All computations have been performed on personal computer using the Gaussian 03 program package. The calculations were adapted to Cs symmetries of all the molecules. The O-trans rotomers with lower energy of all the molecules have been found as preferential rotomers in the ground state.
Energy Technology Data Exchange (ETDEWEB)
Lara-Castells, María Pilar de, E-mail: Pilar.deLara.Castells@csic.es; Bartolomei, Massimiliano [Instituto de Física Fundamental (C.S.I.C.), Serrano 123, E-28006 Madrid (Spain); Mitrushchenkov, Alexander O. [Laboratoire Modélisation et Simulation Multi Echelle, Université Paris-Est, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée (France); Stoll, Hermann [Institut für Theoretische Chemie, Universität Stuttgart, D-70550 Stuttgart (Germany)
2015-11-21
The accuracy and transferability of the electronic structure approach combining dispersionless density functional theory (DFT) [K. Pernal et al., Phys. Rev. Lett. 103, 263201 (2009)] with the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)], are validated for the interaction between the noble-gas Ne, Ar, Kr, and Xe atoms and coronene/graphene/graphite surfaces. This approach uses the method of increments for surface cluster models to extract intermonomer dispersion-like (2- and 3-body) correlation terms at coupled cluster singles and doubles and perturbative triples level, while periodic dispersionless density functionals calculations are performed to estimate the sum of Hartree-Fock and intramonomer correlation contributions. Dispersion energy contributions are also obtained using DFT-based symmetry-adapted perturbation theory [SAPT(DFT)]. An analysis of the structure of the X/surface (X = Ne, Ar, Kr, and Xe) interaction energies shows the excellent transferability properties of the leading intermonomer correlation contributions across the sequence of noble-gas atoms, which are also discussed using the Drude oscillator model. We further compare these results with van der Waals-(vdW)-corrected DFT-based approaches. As a test of accuracy, the energies of the low-lying nuclear bound states supported by the laterally averaged X/graphite potentials (X = {sup 3}He, {sup 4}He, Ne, Ar, Kr, and Xe) are calculated and compared with the best estimations from experimental measurements and an atom-bond potential model using the ab initio-assisted fine-tuning of semiempirical parameters. The bound-state energies determined differ by less than 6–7 meV (6%) from the atom-bond potential model. The crucial importance of including incremental 3-body dispersion-type terms is clearly demonstrated, showing that the SAPT(DFT) approach effectively account for these terms. With the deviations from the best experimental-based estimations smaller than 2.3 meV (1.9%), the
Collective gyromagnetic ratio and moment of inertia from density-dependent Hartree-Fock calculations
International Nuclear Information System (INIS)
Sprung, D.W.L.; Lie, S.G.; Vallieres, M.; Quentin, P.
1979-01-01
The collective gyromagnetic ratio and moment of inertia of deformed even-even axially symmetric nuclei are calculated in the cranking approximation using wave functions obtained with the Skyrme force S-III. Good agreement is found for gsub(R), while the moment of inertia is about 20% too small. The cranking formula leads to better agreement than the projection method. (Auth.)
International Nuclear Information System (INIS)
Delta, E.; Ucun, F.; Saglam, A.
2010-01-01
The ground state hydrogen conformations of 1,2-dihydroxyanthraquinone (alizarin) molecule have been investigated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-31G(d,p) basis set. The calculations indicate that the compound in the ground state exist with the doubly bonded O atom linked intra molecularly by the two hydrogen bonds. The vibrational analyses of the ground state conformation of the compound were also made and its optimized geometry parameters were given.
International Nuclear Information System (INIS)
Sert, Y.
2008-01-01
The optimised molecular structure, vibrational frequencies and corresponding vibrational assignments of 2-, 3- and 4- nitro anilines have been calculated using the Hartree-Fock (HF) and density functional methods (B3LYP) with 6-311++G (d, p) basis set. The calculations were adapted to the C S symmetries of all the molecules. The calculated vibrational frequencies and geometric parameters (bond lengths and bond angles) were seen to be in good agreement with the experimental data. The comparison of the experimental and theoretical results showed that the HF method is superior to the B3LYP method for both the vibrational frequencies and geometric parameters
International Nuclear Information System (INIS)
Cowan, R.D.; Grant, I.P.; Fawcett, B.C.; Rose, S.J.
1985-11-01
A Multi-Configuration-Dirac-Fock (MCDF) computer program is adapted to interface with the Hartree-Fock-Relativistic (HFR) program for the RAL IBM mainframe computer. The two codes are integrated into a package which includes the Zeeman Laboratory Slater parameter optimisation routines as well as new RAL routines to further process the HFR and MCDF output. A description of the adaptions to MCDF and new output extensions is included in this report, and details are given regarding HFR FORTRAN subroutines, and lists of Job Control Language (JCL) files for the complete package. (author)
International Nuclear Information System (INIS)
Dey, J.; Dey, M.; Mukhopadhyay, G.; Samanta, B.C.
1989-01-01
Mean field models of the nucleon and the delta are established with the two-quark vector Richardson potential along with various prescriptions for a running quark mass. This is taken to be a one-particle operator in the Dirac-Hartree Fock formalism. An effective density dependent one body potential U(ρ) for quarks at a given density ρ inside the nucleon is derived. It shows an interesting structure. Asymptotic freedom and confinement properties are built-in at high and low densities in U (ρ) and the model dependence is restricted to the intermediate desnsities. (author) [pt
Roothaan approach in the thermodynamic limit
Gutierrez, G.; Plastino, A.
1982-02-01
A systematic method for the solution of the Hartree-Fock equations in the thermodynamic limit is presented. The approach is seen to be a natural extension of the one usually employed in the finite-fermion case, i.e., that developed by Roothaan. The new techniques developed here are applied, as an example, to neutron matter, employing the so-called V1 Bethe "homework" potential. The results obtained are, by far, superior to those that the ordinary plane-wave Hartree-Fock theory yields. NUCLEAR STRUCTURE Hartree-Fock approach; nuclear and neutron matter.
Symmetry-projected variational approach to the one-dimensional Hubbard model
International Nuclear Information System (INIS)
Schmid, K.W.; Dahm, T.; Margueron, J.; Muether, H.
2005-01-01
We apply a variational method devised for the nuclear many-body problem to the one-dimensional Hubbard model with nearest neighbor hopping and periodic boundary conditions. The test wave function consist for each state out of a single Hartree-Fock determinant mixing all the sites (or momenta) as well as the spin projections of the electrons. Total spin and linear momentum are restored by projection methods before the variation. It is demonstrated that this approach reproduces the results of exact diagonalizations for half-filled N=12 and N=14 lattices not only for the energies and occupation numbers of the ground but also of the lowest excited states rather well. Furthermore, a system of ten electrons in an N=12 lattice is investigated and, finally, an N=30 lattice is studied. In addition to energies and occupation numbers we present the spectral functions computed with the help of the symmetry-projected wave functions as well
Directory of Open Access Journals (Sweden)
Kedziora David J.
2011-10-01
Full Text Available Collisions of actinide nuclei form, during very short times of few zs (10−21 s, the heaviest ensembles of interacting nucleons available on Earth. Such collisions are used to produce super-strong electric ﬁelds by the huge number of interacting protons to test spontaneous positron-electron pair emission (vacuum decay predicted by the quantum electrodynamics (QED theory. Multi-nucleon transfer in actinide collisions could also be used as an alternative way to fusion in order to produce neutron-rich heavy and superheavy elements thanks to inverse quasiﬁssion mechanisms. Actinide collisions are studied in a dynamical quantum microscopic approach. The three-dimensional time-dependent Hartree-Fock (TDHF code tdhf3d is used with a full Skyrme energy density functional to investigate the time evolution of expectation values of one-body operators, such as fragment position and particle number. This code is also used to compute the dispersion of the particle numbers (e.g., widths of fragment mass and charge distributions from TDHF transfer probabilities, on the one hand, and using the BalianVeneroni variational principle, on the other hand. A ﬁrst application to test QED is discussed. Collision times in 238U+238U are computed to determine the optimum energy for the observation of the vacuum decay. It is shown that the initial orientation strongly affects the collision times and reaction mechanism. The highest collision times predicted by TDHF in this reaction are of the order of ~ 4 zs at a center of mass energy of 1200 MeV. According to modern calculations based on the Dirac equation, the collision times at Ecm > 1 GeV are suﬃcient to allow spontaneous electron-positron pair emission from QED vacuum decay, in case of bare uranium ion collision. A second application of actinide collisions to produce neutron-rich transfermiums is discussed. A new inverse quasiﬁssion mechanism associated to a speciﬁc orientation of the nuclei is proposed to
Kruse, Holger; Grimme, Stefan
2012-04-21
A semi-empirical counterpoise-type correction for basis set superposition error (BSSE) in molecular systems is presented. An atom pair-wise potential corrects for the inter- and intra-molecular BSSE in supermolecular Hartree-Fock (HF) or density functional theory (DFT) calculations. This geometrical counterpoise (gCP) denoted scheme depends only on the molecular geometry, i.e., no input from the electronic wave-function is required and hence is applicable to molecules with ten thousands of atoms. The four necessary parameters have been determined by a fit to standard Boys and Bernadi counterpoise corrections for Hobza's S66×8 set of non-covalently bound complexes (528 data points). The method's target are small basis sets (e.g., minimal, split-valence, 6-31G*), but reliable results are also obtained for larger triple-ζ sets. The intermolecular BSSE is calculated by gCP within a typical error of 10%-30% that proves sufficient in many practical applications. The approach is suggested as a quantitative correction in production work and can also be routinely applied to estimate the magnitude of the BSSE beforehand. The applicability for biomolecules as the primary target is tested for the crambin protein, where gCP removes intramolecular BSSE effectively and yields conformational energies comparable to def2-TZVP basis results. Good mutual agreement is also found with Jensen's ACP(4) scheme, estimating the intramolecular BSSE in the phenylalanine-glycine-phenylalanine tripeptide, for which also a relaxed rotational energy profile is presented. A variety of minimal and double-ζ basis sets combined with gCP and the dispersion corrections DFT-D3 and DFT-NL are successfully benchmarked on the S22 and S66 sets of non-covalent interactions. Outstanding performance with a mean absolute deviation (MAD) of 0.51 kcal/mol (0.38 kcal/mol after D3-refit) is obtained at the gCP-corrected HF-D3/(minimal basis) level for the S66 benchmark. The gCP-corrected B3LYP-D3/6-31G* model
Kruse, Holger; Grimme, Stefan
2012-04-01
A semi-empirical counterpoise-type correction for basis set superposition error (BSSE) in molecular systems is presented. An atom pair-wise potential corrects for the inter- and intra-molecular BSSE in supermolecular Hartree-Fock (HF) or density functional theory (DFT) calculations. This geometrical counterpoise (gCP) denoted scheme depends only on the molecular geometry, i.e., no input from the electronic wave-function is required and hence is applicable to molecules with ten thousands of atoms. The four necessary parameters have been determined by a fit to standard Boys and Bernadi counterpoise corrections for Hobza's S66×8 set of non-covalently bound complexes (528 data points). The method's target are small basis sets (e.g., minimal, split-valence, 6-31G*), but reliable results are also obtained for larger triple-ζ sets. The intermolecular BSSE is calculated by gCP within a typical error of 10%-30% that proves sufficient in many practical applications. The approach is suggested as a quantitative correction in production work and can also be routinely applied to estimate the magnitude of the BSSE beforehand. The applicability for biomolecules as the primary target is tested for the crambin protein, where gCP removes intramolecular BSSE effectively and yields conformational energies comparable to def2-TZVP basis results. Good mutual agreement is also found with Jensen's ACP(4) scheme, estimating the intramolecular BSSE in the phenylalanine-glycine-phenylalanine tripeptide, for which also a relaxed rotational energy profile is presented. A variety of minimal and double-ζ basis sets combined with gCP and the dispersion corrections DFT-D3 and DFT-NL are successfully benchmarked on the S22 and S66 sets of non-covalent interactions. Outstanding performance with a mean absolute deviation (MAD) of 0.51 kcal/mol (0.38 kcal/mol after D3-refit) is obtained at the gCP-corrected HF-D3/(minimal basis) level for the S66 benchmark. The gCP-corrected B3LYP-D3/6-31G* model
Perez, R. Navarro; Schunck, N.; Lasseri, R.-D.; Zhang, C.; Sarich, J.
2017-11-01
We describe the new version 3.00 of the code HFBTHO that solves the nuclear Hartree-Fock (HF) or Hartree-Fock-Bogolyubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the full Gogny force in both particle-hole and particle-particle channels, (ii) the calculation of the nuclear collective inertia at the perturbative cranking approximation, (iii) the calculation of fission fragment charge, mass and deformations based on the determination of the neck, (iv) the regularization of zero-range pairing forces, (v) the calculation of localization functions, (vi) a MPI interface for large-scale mass table calculations. Program Files doi:http://dx.doi.org/10.17632/c5g2f92by3.1 Licensing provisions: GPL v3 Programming language: FORTRAN-95 Journal reference of previous version: M.V. Stoitsov, N. Schunck, M. Kortelainen, N. Michel, H. Nam, E. Olsen, J. Sarich, and S. Wild, Comput. Phys. Commun. 184 (2013). Does the new version supersede the previous one: Yes Summary of revisions: 1. the Gogny force in both particle-hole and particle-particle channels was implemented; 2. the nuclear collective inertia at the perturbative cranking approximation was implemented; 3. fission fragment charge, mass and deformations were implemented based on the determination of the position of the neck between nascent fragments; 4. the regularization method of zero-range pairing forces was implemented; 5. the localization functions of the HFB solution were implemented; 6. a MPI interface for large-scale mass table calculations was implemented. Nature of problem:HFBTHO is a physics computer code that is used to model the structure of the nucleus. It is an implementation of the energy density functional (EDF) approach to atomic nuclei, where the energy of the nucleus is obtained by integration over space of some phenomenological energy density, which is itself a functional of the neutron and proton
Vikramaditya, Talapunur; Lin, Shiang-Tai
2017-06-05
Accurate determination of ionization potentials (IPs), electron affinities (EAs), fundamental gaps (FGs), and HOMO, LUMO energy levels of organic molecules play an important role in modeling and predicting the efficiencies of organic photovoltaics, OLEDs etc. In this work, we investigate the effects of Hartree Fock (HF) Exchange, correlation energy, and long range corrections in predicting IP and EA in Hybrid Functionals. We observe increase in percentage of HF exchange results in increase of IPs and decrease in EAs. Contrary to the general expectations inclusion of both HF exchange and correlation energy (from the second order perturbation theory MP2) leads to poor prediction. Range separated Hybrid Functionals are found to be more reliable among various DFT Functionals investigated. DFT Functionals predict accurate IPs whereas post HF methods predict accurate EAs. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.
Ucun, Fatih; Sağlam, Adnan; Güçlü, Vesile
2007-06-01
The molecular structures, vibrational frequencies and corresponding vibrational assignments of xanthine and its methyl derivatives (caffeine and theobromine) have been calculated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-31G(d, p) basis set level. The calculations were utilized to the CS symmetries of the molecules. The obtained vibrational frequencies and optimised geometric parameters (bond lengths and bond angles) were seen to be well agreement with the experimental data. The used scale factors which have been obtained the ratio of the frequency values of the strongest peaks in the calculated and experimental spectra seem to cause the gained vibrations well corresponding to the experimental ones. Theoretical infrared intensities and Raman activities are also reported.
Yoshida, Tatsusada; Hayashi, Takahisa; Mashima, Akira; Chuman, Hiroshi
2015-10-01
One of the most challenging problems in computer-aided drug discovery is the accurate prediction of the binding energy between a ligand and a protein. For accurate estimation of net binding energy ΔEbind in the framework of the Hartree-Fock (HF) theory, it is necessary to estimate two additional energy terms; the dispersion interaction energy (Edisp) and the basis set superposition error (BSSE). We previously reported a simple and efficient dispersion correction, Edisp, to the Hartree-Fock theory (HF-Dtq). In the present study, an approximation procedure for estimating BSSE proposed by Kruse and Grimme, a geometrical counterpoise correction (gCP), was incorporated into HF-Dtq (HF-Dtq-gCP). The relative weights of the Edisp (Dtq) and BSSE (gCP) terms were determined to reproduce ΔEbind calculated with CCSD(T)/CBS or /aug-cc-pVTZ (HF-Dtq-gCP (scaled)). The performance of HF-Dtq-gCP (scaled) was compared with that of B3LYP-D3(BJ)-bCP (dispersion corrected B3LYP with the Boys and Bernadi counterpoise correction (bCP)), by taking ΔEbind (CCSD(T)-bCP) of small non-covalent complexes as 'a golden standard'. As a critical test, HF-Dtq-gCP (scaled)/6-31G(d) and B3LYP-D3(BJ)-bCP/6-31G(d) were applied to the complex model for HIV-1 protease and its potent inhibitor, KNI-10033. The present results demonstrate that HF-Dtq-gCP (scaled) is a useful and powerful remedy for accurately and promptly predicting ΔEbind between a ligand and a protein, albeit it is a simple correction procedure. Copyright © 2015 Elsevier Ltd. All rights reserved.
Caffarel, Michel; Giner, Emmanuel; Scemama, Anthony; Ramírez-Solís, Alejandro
2014-12-09
We present a comparative study of the spatial distribution of the spin density of the ground state of CuCl2 using Density Functional Theory (DFT), quantum Monte Carlo (QMC), and post-Hartree-Fock wave function theory (WFT). A number of studies have shown that an accurate description of the electronic structure of the lowest-lying states of this molecule is particularly challenging due to the interplay between the strong dynamical correlation effects in the 3d shell and the delocalization of the 3d hole over the chlorine atoms. More generally, this problem is representative of the difficulties encountered when studying open-shell metal-containing molecular systems. Here, it is shown that qualitatively different results for the spin density distribution are obtained from the various quantum-mechanical approaches. At the DFT level, the spin density distribution is found to be very dependent on the functional employed. At the QMC level, Fixed-Node Diffusion Monte Carlo (FN-DMC) results are strongly dependent on the nodal structure of the trial wave function. Regarding wave function methods, most approaches not including a very high amount of dynamic correlation effects lead to a much too high localization of the spin density on the copper atom, in sharp contrast with DFT. To shed some light on these conflicting results Full CI-type (FCI) calculations using the 6-31G basis set and based on a selection process of the most important determinants, the so-called CIPSI approach (Configuration Interaction with Perturbative Selection done Iteratively) are performed. Quite remarkably, it is found that for this 63-electron molecule and a full CI space including about 10(18) determinants, the FCI limit can almost be reached. Putting all results together, a natural and coherent picture for the spin distribution is proposed.
Schunck, N.; Dobaczewski, J.; McDonnell, J.; Satuła, W.; Sheikh, J. A.; Staszczak, A.; Stoitsov, M.; Toivanen, P.
2012-01-01
We describe the new version (v2.49t) of the code HFODD which solves the nuclear Skyrme-Hartree-Fock (HF) or Skyrme-Hartree-Fock-Bogolyubov (HFB) problem by using the Cartesian deformed harmonic-oscillator basis. In the new version, we have implemented the following physics features: (i) the isospin mixing and projection, (ii) the finite-temperature formalism for the HFB and HF + BCS methods, (iii) the Lipkin translational energy correction method, (iv) the calculation of the shell correction. A number of specific numerical methods have also been implemented in order to deal with large-scale multi-constraint calculations and hardware limitations: (i) the two-basis method for the HFB method, (ii) the Augmented Lagrangian Method (ALM) for multi-constraint calculations, (iii) the linear constraint method based on the approximation of the RPA matrix for multi-constraint calculations, (iv) an interface with the axial and parity-conserving Skyrme-HFB code HFBTHO, (v) the mixing of the HF or HFB matrix elements instead of the HF fields. Special care has been paid to using the code on massively parallel leadership class computers. For this purpose, the following features are now available with this version: (i) the Message Passing Interface (MPI) framework, (ii) scalable input data routines, (iii) multi-threading via OpenMP pragmas, (iv) parallel diagonalization of the HFB matrix in the simplex-breaking case using the ScaLAPACK library. Finally, several little significant errors of the previous published version were corrected. New version program summaryProgram title:HFODD (v2.49t) Catalogue identifier: ADFL_v3_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADFL_v3_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence v3 No. of lines in distributed program, including test data, etc.: 190 614 No. of bytes in distributed program, including test data, etc.: 985 898 Distribution
Directory of Open Access Journals (Sweden)
H. Mariji
2016-01-01
Full Text Available The nucleon single-particle energies (SPEs of the selected nuclei, that is, O16, Ca40, and Ni56, are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest-order constrained variational (LOCV calculations for the symmetric nuclear matter with the Aυ18 phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing a Hartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-body momentum distribution functions of nucleons, n(k,ρ, with the Heaviside functions, the role of n(k,ρ in the nucleon SPEs at the major levels of the selected closed shell nuclei is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterized Wood-Saxon potential and the Aυ18 density-dependent mean field potential which is constructed by the LOCV method. Considering the point-like protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including n(k,ρ, instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.
Hesselmann, Andreas; Görling, Andreas
2011-01-21
A recently introduced time-dependent exact-exchange (TDEXX) method, i.e., a response method based on time-dependent density-functional theory that treats the frequency-dependent exchange kernel exactly, is reformulated. In the reformulated version of the TDEXX method electronic excitation energies can be calculated by solving a linear generalized eigenvalue problem while in the original version of the TDEXX method a laborious frequency iteration is required in the calculation of each excitation energy. The lowest eigenvalues of the new TDEXX eigenvalue equation corresponding to the lowest excitation energies can be efficiently obtained by, e.g., a version of the Davidson algorithm appropriate for generalized eigenvalue problems. Alternatively, with the help of a series expansion of the new TDEXX eigenvalue equation, standard eigensolvers for large regular eigenvalue problems, e.g., the standard Davidson algorithm, can be used to efficiently calculate the lowest excitation energies. With the help of the series expansion as well, the relation between the TDEXX method and time-dependent Hartree-Fock is analyzed. Several ways to take into account correlation in addition to the exact treatment of exchange in the TDEXX method are discussed, e.g., a scaling of the Kohn-Sham eigenvalues, the inclusion of (semi)local approximate correlation potentials, or hybrids of the exact-exchange kernel with kernels within the adiabatic local density approximation. The lowest lying excitations of the molecules ethylene, acetaldehyde, and pyridine are considered as examples.
Song, Jong-Won; Hirao, Kimihiko
2015-10-14
Since the advent of hybrid functional in 1993, it has become a main quantum chemical tool for the calculation of energies and properties of molecular systems. Following the introduction of long-range corrected hybrid scheme for density functional theory a decade later, the applicability of the hybrid functional has been further amplified due to the resulting increased performance on orbital energy, excitation energy, non-linear optical property, barrier height, and so on. Nevertheless, the high cost associated with the evaluation of Hartree-Fock (HF) exchange integrals remains a bottleneck for the broader and more active applications of hybrid functionals to large molecular and periodic systems. Here, we propose a very simple yet efficient method for the computation of long-range corrected hybrid scheme. It uses a modified two-Gaussian attenuating operator instead of the error function for the long-range HF exchange integral. As a result, the two-Gaussian HF operator, which mimics the shape of the error function operator, reduces computational time dramatically (e.g., about 14 times acceleration in C diamond calculation using periodic boundary condition) and enables lower scaling with system size, while maintaining the improved features of the long-range corrected density functional theory.
López-Quelle, M.; Marcos, S.; Niembro, R.; Savushkin, L. N.
2018-03-01
Within a nonlinear relativistic Hartree-Fock approximation combined with the BCS method, we study the effect of the nucleon-nucleon tensor force of the π-exchange potential on the spin- and pseudospin-orbit doublets along the Ca and Sn isotopic chains. We show how the self-consistent tensor force effect modifies the splitting of both kinds of doublets in an interdependent form, leading, quite generally, to opposite effects in the accomplishment of the spin and pseudospin symmetries (the one is restored, the other one deteriorates and vice versa). The ordering of the single-particle energy levels is crucial to this respect. Also, we observe a mutual dependence on the evolution of the shell closure gap Z = 50 and the energy band outside the core, along the Sn chain, as due to the tensor force. In fact, when the shell gap is quenched the outside energy band is enlarged, and vice versa. A reduction of the strength of the pion tensor force with respect to its experimental value from the nucleon-nucleon scattering is needed to get results closer to the experiment. Pairing correlations act to some extent in the opposite direction of the tensor term of the one-pion-exchange force.
Arslan, Hakan; Mansuroglu, Demet Sezgin; VanDerveer, Don; Binzet, Gun
2009-04-01
N-(2,2-Diphenylacetyl)- N'-(naphthalen-1yl)-thiourea (PANT) has been synthesized and characterized by elemental analysis, IR spectroscopy and 1H NMR spectroscopy. The crystal and molecular structure of the title compound has been determined from single crystal X-ray diffraction data. It crystallizes in the triclinic space group P-1, Z = 2 with a = 10.284(2) Å, b = 10.790(2) Å, c = 11.305(2) Å, α = 64.92(3)°, β = 89.88(3)°, γ = 62.99(3)°, V = 983.7(3) Å 3 and Dcalc = 1.339 Mg/m 3. The molecular structure, vibrational frequencies and infrared intensities of PANT were calculated by the Hartree-Fock and density functional theory methods (BLYP and B3LYP) using the 6-31G* basis set. The calculated geometric parameters were compared to the corresponding X-ray structure of the title compound. We obtained 22 stable conformers for the title compound; however Conformer 1 is approximately 9.53 kcal/mol more stable than Conformer 22. The comparison of the theoretical and experimental geometry of the title compound shows that the X-ray parameters fairly well reproduce the geometry of Conformer 17. The harmonic vibrations computed for this compound by the B3LYP/6-31G* method are in good agreement with the observed IR spectral data. Theoretical vibrational spectra of the title compound were interpreted by means of PEDs using the VEDA 4 program. A general better performance of the investigated methods was calculated by PAVF 1.0 program.
International Nuclear Information System (INIS)
Dagens, L.
1975-01-01
The neutral atom method is generalized in order to deal with a Hartree-Fock nonlocal ionic potential. It is used to test the following metal potential, based upon a theoretical analysis due to Hedin and Lundquist. The true HF potential is used to describe the ionic part and a simple local density scheme (the Gaspar-Kohn-Sham approximation) is used for the valence part. The method is first applied to the calculation of the rigid neutral atom valence density of a few simple metals and the corresponding form factor n(q). The choice of the ionic potential (HF or GKS) is found to have a small but significant effect as far as n(q) is concerned. A comparison with experiment is made for Al and Be, using the available X-rays structure factor measurements. Good agreement is obtained for Al with the recent results of Raccah and Heinrich. No agreement is obtained with the Be results of Brown, although the general behavior of the observed and theoretical n(g) as function of g (reciprocal vector length) are found to be quite similar. The binding energy is calculated for Li, Be, Na, Mg and Al, using the Nozieres-Pines formula for the valence-valence correlation energy. The agreement with observed values is improved considerably when the present (HF+GKS) scheme is used, instead of the HFS completely local density scheme used in a previous work. The remaining discrepancies may be ascribed to the inaccuracy of the NP formula and to the neglect of the whole valence-core correlation energy [fr
Czech Academy of Sciences Publication Activity Database
Řezáč, Jan; Riley, Kevin Eugene; Hobza, Pavel
2012-01-01
Roč. 33, č. 6 (2012), s. 691-694 ISSN 0192-8651 R&D Projects: GA MŠk LC512 Grant - others:European Social Fund(XE) CZ.1.05/2.1.00/03.0058 Institutional research plan: CEZ:AV0Z40550506 Keywords : post-HF methods * molecular geometry * benchmark calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.835, year: 2012
Energy Technology Data Exchange (ETDEWEB)
Lara-Castells, María Pilar de, E-mail: Pilar.deLara.Castells@csic.es [Instituto de Física Fundamental (CSIC), Serrano 123, E-28006 Madrid (Spain); Fernández-Perea, Ricardo [Instituto de Estructura de la Materia (CSIC), Serrano 123, E-28006 Madrid (Spain); Madzharova, Fani; Voloshina, Elena, E-mail: elena.voloshina@hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Chemie, Unter den Linden 6, 10099 Berlin (Germany)
2016-06-28
The adsorption of noble gases on metallic surfaces represents a paradigmatic case of van-der-Waals (vdW) interaction due to the role of screening effects on the corrugation of the interaction potential [J. L. F. Da Silva et al., Phys. Rev. Lett. 90, 066104 (2003)]. The extremely small adsorption energy of He atoms on the Mg(0001) surface (below 3 meV) and the delocalized nature and mobility of the surface electrons make the He/Mg(0001) system particularly challenging, even for state-of-the-art vdW-corrected density functional-based (vdW-DFT) approaches [M. P. de Lara-Castells et al., J. Chem. Phys. 143, 194701 (2015)]. In this work, we meet this challenge by applying two different procedures. First, the dispersion-corrected second-order Möller-Plesset perturbation theory (MP2C) approach is adopted, using bare metal clusters of increasing size. Second, the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)] is applied at coupled cluster singles and doubles and perturbative triples level, using embedded cluster models of the metal surface. Both approaches provide clear evidences of the anti-corrugation of the interaction potential: the He atom prefers on-top sites, instead of the expected hollow sites. This is interpreted as a signature of the screening of the He atom by the metal for the on-top configuration. The strong screening in the metal is clearly reflected in the relative contribution of successively deeper surface layers to the main dispersion contribution. Aimed to assist future dynamical simulations, a pairwise potential model for the He/surface interaction as a sum of effective He–Mg pair potentials is also presented, as an improvement of the approximation using isolated He–Mg pairs.
International Nuclear Information System (INIS)
Schmidt, M.W.; Ruedenberg, K.
1979-01-01
Optimal starting points for expanding molecular orbitals in terms of atomic orbitals are the self-consistent-field orbitals of the free atoms and accurate information about the latter is essential for the construction of effective AO bases for molecular calculations. For expansions of atomic SCF orbitals in terms of Gaussian primitives, which are of particular interest for applications in polyatomic quantum chemistry, previous information has been limited in accuracy. In the present investigation a simple procedure is given for finding expansions of atomic self-consistent-field orbitals in terms of Gaussian primitives to arbitrarily high accuracy. The method furthermore opens the first avenue so far for approaching complete basis sets through systematic sequences of atomic orbitals
Hermes, Matthew R; Hirata, So
2015-09-14
One-dimensional (1D) solids exhibit a number of striking electronic structures including charge-density wave (CDW) and spin-density wave (SDW). Also, the Peierls theorem states that at zero temperature, a 1D system predicted by simple band theory to be a metal will spontaneously dimerize and open a finite fundamental bandgap, while at higher temperatures, it will assume the equidistant geometry with zero bandgap (a Peierls transition). We computationally study these unique electronic structures and transition in polyyne and all-trans polyacetylene using finite-temperature generalizations of ab initio spin-unrestricted Hartree-Fock (UHF) and spin-restricted coupled-cluster doubles (CCD) theories, extending upon previous work [He et al., J. Chem. Phys. 140, 024702 (2014)] that is based on spin-restricted Hartree-Fock (RHF) and second-order many-body perturbation (MP2) theories. Unlike RHF, UHF can predict SDW as well as CDW and metallic states, and unlike MP2, CCD does not diverge even if the underlying RHF reference wave function is metallic. UHF predicts a gapped SDW state with no dimerization at low temperatures, which gradually becomes metallic as the temperature is raised. CCD, meanwhile, confirms that electron correlation lowers the Peierls transition temperature. Furthermore, we show that the results from all theories for both polymers are subject to a unified interpretation in terms of the UHF solutions to the Hubbard-Peierls model using different values of the electron-electron interaction strength, U/t, in its Hamiltonian. The CCD wave function is shown to encompass the form of the exact solution of the Tomonaga-Luttinger model and is thus expected to describe accurately the electronic structure of Luttinger liquids.
Rolke, J.; Brion, C. E.
1996-06-01
The spherically averaged momentum profiles for the highest occupied molecular orbitals of PF 3 and P(CH 3) 3 have been obtained by electron momentum spectroscopy. The measurements provide a stringent test of basis set effects and the quality of ab-initio methods in the description of these larger molecular systems. As in previous work on the methyl-substituted amines, intuitive arguments fail to predict the correct amount of s- and p-type contributions to the momentum profile while delocalized molecular orbital concepts provide a more adequate description of the HOMOs. The experimental momentum profiles have been compared with theoretical momentum profiles calculated at the level of the target Hartree-Fock approximation with a range of basis sets. New Hartree-Fock calculations are also presented for the HOMO of PH 3 and compared to previously published experimental and theoretical momentum profiles. The experimental momentum profiles have further been compared to calculations at the level of the target Kohn-Sham approximation using density functional theory with the local density approximation and also with gradient corrected (non-local) exchange correlation potentials. In addition, total energies and dipole moments have been calculated for all three molecules by the various theoretical methods and compared to experimental values. Calculated 'density difference maps' show the regions where the HOMO momentum and position electron densities of PF 3 and P(CH 3) 3 change relative to the corresponding HOMO density of PH 3. The results suggest that methyl groups have an electron-attracting effect (relative to H) on the HOMO charge density in trimethyl phosphines. These conclusions are supported by a consideration of dipole moments and the 31P NMR chemical shifts for PH 3, PF 3 and P(CH 3) 3.
Roothaan approach in the thermodynamic limit
International Nuclear Information System (INIS)
Gutierrez, G.; Plastino, A.
1982-01-01
A systematic method for the solution of the Hartree-Fock equations in the thermodynamic limit is presented. The approach is seen to be a natural extension of the one usually employed in the finite-fermion case, i.e., that developed by Roothaan. The new techniques developed here are applied, as an example, to neutron matter, employing the so-called V 1 Bethe homework potential. The results obtained are, by far, superior to those that the ordinary plane-wave Hartree-Fock theory yields
Projected quasiparticle theory for molecular electronic structure
Scuseria, Gustavo E.; Jiménez-Hoyos, Carlos A.; Henderson, Thomas M.; Samanta, Kousik; Ellis, Jason K.
2011-09-01
We derive and implement symmetry-projected Hartree-Fock-Bogoliubov (HFB) equations and apply them to the molecular electronic structure problem. All symmetries (particle number, spin, spatial, and complex conjugation) are deliberately broken and restored in a self-consistent variation-after-projection approach. We show that the resulting method yields a comprehensive black-box treatment of static correlations with effective one-electron (mean-field) computational cost. The ensuing wave function is of multireference character and permeates the entire Hilbert space of the problem. The energy expression is different from regular HFB theory but remains a functional of an independent quasiparticle density matrix. All reduced density matrices are expressible as an integration of transition density matrices over a gauge grid. We present several proof-of-principle examples demonstrating the compelling power of projected quasiparticle theory for quantum chemistry.
Rabilloud, Franck
2014-10-14
Absorption spectra of Ag20 and Ag55(q) (q = +1, -3) nanoclusters are investigated in the framework of the time-dependent density functional theory in order to analyse the role of the d electrons in plasmon-like band of silver clusters. The description of the plasmon-like band from calculations using density functionals containing an amount of Hartree-Fock exchange at long range, namely, hybrid and range-separated hybrid (RSH) density functionals, is in good agreement with the classical interpretation of the plasmon-like structure as a collective excitation of valence s-electrons. In contrast, using local or semi-local exchange functionals (generalized gradient approximations (GGAs) or meta-GGAs) leads to a strong overestimation of the role of d electrons in the plasmon-like band. The semi-local asymptotically corrected model potentials also describe the plasmon as mainly associated to d electrons, though calculated spectra are in fairly good agreement with those calculated using the RSH scheme. Our analysis shows that a portion of non-local exchange modifies the description of the plasmon-like band.
Microscopic optical potential for 208Pb in the nuclear structure approach
International Nuclear Information System (INIS)
Bernard, V.; Nguyen Van Gai.
1979-04-01
The optical potential for nucleon- 208 Pb scattering below 30 MeV is calculated microscopically as the sum of a real Hartree-Fock term and a complex correction term arising from the coupling to excited states of the target. The Skyrme effective interaction is used to generate the Hartree-Fock field, the RPA excited states and the coupling. A complex local equivalent potential is defined and used to calculate scattering and absorption cross-sections. The real part of the optical potential is reasonably well described in this approach while the imaginary part is too weak. Inclusion of rearrangement processes could improve the agreement with experiment
Ohmura, S.; Kato, T.; Oyamada, T.; Koseki, S.; Ohmura, H.; Kono, H.
2018-02-01
The mechanisms of anisotropic near-IR tunnel ionization and high-order harmonic generation (HHG) in a CO molecule are theoretically investigated by using the multiconfiguration time-dependent Hartree-Fock (MCTDHF) method developed for the simulation of multielectron dynamics of molecules. The multielectron dynamics obtained by numerically solving the equations of motion (EOMs) in the MCTDHF method is converted to a single orbital picture in the natural orbital representation where the first-order reduced density matrix is diagonalized. The ionization through each natural orbital is examined and the process of HHG is classified into different optical paths designated by a combinations of initial, intermediate and final natural orbitals. The EOMs for natural spin-orbitals are also derived within the framework of the MCTDHF, which maintains the first-order reduced density matrix to be a diagonal one throughout the time propagation of a many-electron wave function. The orbital dependent, time-dependent effective potentials that govern the dynamics of respective time-dependent natural orbitals are deduced from the derived EOMs, of which the temporal variation can be used to interpret the motion of the electron density associated with each natural spin-orbital. The roles of the orbital shape, multiorbital ionization, linear Stark effect and multielectron interaction in the ionization and HHG of a CO molecule are revealed by the effective potentials obtained. When the laser electric field points to the nucleus O from C, tunnel ionization from the C atom side is enhanced; a hump structure originating from multielectron interaction is then formed on the top of the field-induced distorted barrier of the HOMO effective potential. This hump formation, responsible for the directional anisotropy of tunnel ionization, restrains the influence of the linear Stark effect on the energy shifts of bound states.
Stoitsov, M. V.; Schunck, N.; Kortelainen, M.; Michel, N.; Nam, H.; Olsen, E.; Sarich, J.; Wild, S.
2013-06-01
We describe the new version 2.00d of the code HFBTHO that solves the nuclear Skyrme-Hartree-Fock (HF) or Skyrme-Hartree-Fock-Bogoliubov (HFB) problem by using the cylindrical transformed deformed harmonic oscillator basis. In the new version, we have implemented the following features: (i) the modified Broyden method for non-linear problems, (ii) optional breaking of reflection symmetry, (iii) calculation of axial multipole moments, (iv) finite temperature formalism for the HFB method, (v) linear constraint method based on the approximation of the Random Phase Approximation (RPA) matrix for multi-constraint calculations, (vi) blocking of quasi-particles in the Equal Filling Approximation (EFA), (vii) framework for generalized energy density with arbitrary density-dependences, and (viii) shared memory parallelism via OpenMP pragmas. Program summaryProgram title: HFBTHO v2.00d Catalog identifier: ADUI_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADUI_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 167228 No. of bytes in distributed program, including test data, etc.: 2672156 Distribution format: tar.gz Programming language: FORTRAN-95. Computer: Intel Pentium-III, Intel Xeon, AMD-Athlon, AMD-Opteron, Cray XT5, Cray XE6. Operating system: UNIX, LINUX, WindowsXP. RAM: 200 Mwords Word size: 8 bits Classification: 17.22. Does the new version supercede the previous version?: Yes Catalog identifier of previous version: ADUI_v1_0 Journal reference of previous version: Comput. Phys. Comm. 167 (2005) 43 Nature of problem: The solution of self-consistent mean-field equations for weakly-bound paired nuclei requires a correct description of the asymptotic properties of nuclear quasi-particle wave functions. In the present implementation, this is achieved by using the single-particle wave functions
DEFF Research Database (Denmark)
Kjærgaard, Thomas; Jørgensen, Poul; Thorvaldsen, Andreas
2009-01-01
A Lagrangian approach has been used to derive gauge-origin independent expressions for two properties that rationalize magneto-optical activity, namely the Verdet constant V(ω) of the Faraday effect and the B term of magnetic circular dichroism. The approach is expressed in terms of an atomic-orb...
Halo nuclei studied by relativistic mean-field approach
International Nuclear Information System (INIS)
Gmuca, S.
1997-01-01
Density distributions of light neutron-rich nuclei are studied by using the relativistic mean-field approach. The effective interaction which parameterizes the recent Dirac-Brueckner-Hartree-Fock calculations of nuclear matter is used. The results are discussed and compared with the experimental observations with special reference to the neutron halo in the drip-line nuclei. (author)
Energy Technology Data Exchange (ETDEWEB)
Lantri, T. [Laboratory of Technology and Solid’s Properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227, Mostaganem 27000 (Algeria); Bentata, S., E-mail: sam_bentata@yahoo.com [Laboratory of Technology and Solid’s Properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227, Mostaganem 27000 (Algeria); Bouadjemi, B.; Benstaali, W. [Laboratory of Technology and Solid’s Properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227, Mostaganem 27000 (Algeria); Bouhafs, B. [Modelling and Simulation in Materials Science Laboratory, Djillali Liabès University of Sidi Bel-Abbès, 22000 Sidi Bel-Abbes (Algeria); Abbad, A. [Laboratory of Technology and Solid’s Properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227, Mostaganem 27000 (Algeria); Modelling and Simulation in Materials Science Laboratory, Djillali Liabès University of Sidi Bel-Abbès, 22000 Sidi Bel-Abbes (Algeria); Zitouni, A. [Laboratory of Technology and Solid’s Properties, Faculty of Sciences and Technology, Abdelhamid Ibn Badis University, BP 227, Mostaganem 27000 (Algeria)
2016-12-01
Using the first-principle calculations, we have investigated the structural, elastic, optoelectronic and magnetic properties of Co{sub 2}MnSi Heusler alloy. Based on the density functional theory (DFT) and hiring the full-potential linearized augmented plane wave (FP-LAPW) method, we have used five approaches: the Hybrid on-site exact exchange, the Local Spin Density Approximation (LSDA), the LSDA+U, the Generalized Gradient Approximation GGA and GGA+U; where the Hubbard on-site Coulomb interaction correction U is calculated by constraint local density approximation for Co and Mn atoms. Our results show that the highly-ordered Co{sub 2}MnSi alloy is a ductile, stiff and anisotropic material. It has a half-metallic ferromagnetic character with an integer magnetic moment of 5 µB which is in good agreement with the Slater-Pauling rule. - Highlights: • Each approach gives a half magnetic compound. • EECE gives the largest gap. • Elastic properties show a stiff, ductile and anisotropic material. • Electronic properties are similar for the five approaches. • Total magnetic moment is the same for the five approaches (5 µB).
Plötner, Jürgen; Tozer, David J; Dreuw, Andreas
2010-08-10
Time-dependent density functional theory (TDDFT) with standard GGA or hybrid exchange-correlation functionals is not capable of describing the potential energy surface of the S1 state of Pigment Yellow 101 correctly; an additional local minimum is observed at a twisted geometry with substantial charge transfer (CT) character. To investigate the influence of nonlocal exact orbital (Hartree-Fock) exchange on the shape of the potential energy surface of the S1 state in detail, it has been computed along the twisting coordinate employing the standard BP86, B3LYP, and BHLYP xc-functionals as well as the long-range separated (LRS) exchange-correlation (xc)-functionals LC-BOP, ωB97X, ωPBE, and CAM-B3LYP and compared to RI-CC2 benchmark results. Additionally, a recently suggested Λ-parameter has been employed that measures the amount of CT in an excited state by calculating the spatial overlap of the occupied and virtual molecular orbitals involved in the transition. Here, the error in the calculated S1 potential energy curves at BP86, B3LYP, and BHLYP can be clearly related to the Λ-parameter, i.e., to the extent of charge transfer. Additionally, it is demonstrated that the CT problem is largely alleviated when the BHLYP xc-functional is employed, although it still exhibits a weak tendency to underestimate the energy of CT states. The situation improves drastically when LRS-functionals are employed within TDDFT excited state calculations. All tested LRS-functionals give qualitatively the correct potential energy curves of the energetically lowest excited states of P. Y. 101 along the twisting coordinate. While LC-BOP and ωB97X overcorrect the CT problem and now tend to give too large excitation energies compared to other non-CT states, ωPBE and CAM-B3LYP are in excellent agreement with the RI-CC2 results, with respect to both the correct shape of the potential energy curve as well as the absolute values of the calculated excitation energies.
Functional approach to a time-dependent self-consistent field theory
International Nuclear Information System (INIS)
Reinhardt, H.
1979-01-01
The time-dependent Hartree-Fock approximation is formulated within the path integral approach. It is shown that by a suitable choice of the collective field the classical equation of motion of the collective field coincides with the time-dependent Hartree (TDH) equation. The consideration is restricted to the TDH equation, since the exchange terms do not appear in the functional approach on the same footing as the direct terms
A microscopic study of the S band in the generator co-ordinate approach
International Nuclear Information System (INIS)
Wuest, E.; Ansari, A.
1985-04-01
Using particle number and spin projected cranked Hartree-Fock-Bogolubov (CHFB) wave functions in the generator co-ordinate method (GCM) with the cranking frequency as a GC the shortcomings of the usual CHFB theory are removed and the ground as well as the s band are studied simultaneously. In particular, low-spin properties of the s band are discussed for a backbending nucleus 158 Dy. (author)
Taşal, Erol; Kumalar, Mustafa
2012-09-01
In this work, the experimental and theoretical spectra of 5-chloro-3-(2-(4-methylpiperazin-1-yl)-2-oxoethyl)benzo[d]thiazol-2(3H)-one molecule (abbreviated as 5CMOT) are studied. The molecular geometry and vibrational frequencies are calculated in the ground state of molecule using ab initio Hartree-Fock (HF) and Density Function Theory (DFT) methods with 6-311++G(d,p), 6-31G++(d,p), 6-31G(d,p), 6-31G(d) and 6-31G basis sets. Three staggered stable conformers were observed on the torsional potential energy surfaces. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes calculated. The comparison of the theoretical and experimental geometries of the title compound indicated that the X-ray parameters fairly well agree with the theoretically obtained values for the most stable conformer. The theoretical results showed an excellent agreement with the experimental values. The calculated HOMO and LUMO energies show that the charge transfer occurs within the molecule. Copyright © 2012 Elsevier B.V. All rights reserved.
Microscopic approach to subthreshold pion production in heavy-ion collisions
International Nuclear Information System (INIS)
Tohyama, M.; Kaps, R.; Masak, D.; Mosel, U.
1985-01-01
A microscopic approach to subthreshold pion production in heavy-ion collisions is proposed, in which the wave function of the nucleon system is approximated in the time-dependent Hartree-Fock theory and an effective interaction for the pion-production process is taken from (p,π) reaction theories. The model is applied to pion production in 16 O + 16 O collisions. (orig.)
Big Data Meets Quantum Chemistry Approximations: The Δ-Machine Learning Approach.
Ramakrishnan, Raghunathan; Dral, Pavlo O; Rupp, Matthias; von Lilienfeld, O Anatole
2015-05-12
Chemically accurate and comprehensive studies of the virtual space of all possible molecules are severely limited by the computational cost of quantum chemistry. We introduce a composite strategy that adds machine learning corrections to computationally inexpensive approximate legacy quantum methods. After training, highly accurate predictions of enthalpies, free energies, entropies, and electron correlation energies are possible, for significantly larger molecular sets than used for training. For thermochemical properties of up to 16k isomers of C7H10O2 we present numerical evidence that chemical accuracy can be reached. We also predict electron correlation energy in post Hartree-Fock methods, at the computational cost of Hartree-Fock, and we establish a qualitative relationship between molecular entropy and electron correlation. The transferability of our approach is demonstrated, using semiempirical quantum chemistry and machine learning models trained on 1 and 10% of 134k organic molecules, to reproduce enthalpies of all remaining molecules at density functional theory level of accuracy.
Correlations and fluctuations in static and dynamic mean-field approaches
International Nuclear Information System (INIS)
Balian, R.; Veneroni, M.
1991-01-01
Let the state of a many-body system at an initial time be specified, completely or partly; find the expectation values, correlations and fluctuations of single-particle observables at a later time. The characteristic function of these observables is optimized within a general variational scheme. The expansion of the optimal characteristic function provides the same results as the conventional mean-field approaches for the thermodynamic potentials and the expectation values: for fermions the best initial state is then the Hartree-Fock (HF) solution and the evolution is described by the time-dependent Hartree-Fock (TDHF) equation. Two special cases are investigated as preliminary steps. The first case deals with the evaluation of correlations for static problems, where the initial and final times coincide. In the second special case, the exact initial state is assumed to be an independent-particle one. (K.A.) 23 refs.; 1 fig
Projected coupled cluster theory.
Qiu, Yiheng; Henderson, Thomas M; Zhao, Jinmo; Scuseria, Gustavo E
2017-08-14
Coupled cluster theory is the method of choice for weakly correlated systems. But in the strongly correlated regime, it faces a symmetry dilemma, where it either completely fails to describe the system or has to artificially break certain symmetries. On the other hand, projected Hartree-Fock theory captures the essential physics of many kinds of strong correlations via symmetry breaking and restoration. In this work, we combine and try to retain the merits of these two methods by applying symmetry projection to broken symmetry coupled cluster wave functions. The non-orthogonal nature of states resulting from the application of symmetry projection operators furnishes particle-hole excitations to all orders, thus creating an obstacle for the exact evaluation of overlaps. Here we provide a solution via a disentanglement framework theory that can be approximated rigorously and systematically. Results of projected coupled cluster theory are presented for molecules and the Hubbard model, showing that spin projection significantly improves unrestricted coupled cluster theory while restoring good quantum numbers. The energy of projected coupled cluster theory reduces to the unprojected one in the thermodynamic limit, albeit at a much slower rate than projected Hartree-Fock.
International Nuclear Information System (INIS)
Ehvarestov, R.A.; Panin, A.I.
2000-01-01
The problem on the possibility of partial accounting for the electron correlation effects within the frames of the Hartree-Fock unlimited method (HF). The local characteristic of the electron structure of the molecular systems for the case of the multi-determinant wave functions, configurational interaction methods and multiconfigurational self-consistent field (MCSCF) are determined. The molecular-crystalline approach is applied to studies on the electron correlation effects in the Ti 2 O 3 crystal. It is shown on the basis of the [Ti 2 O 9 ] 12- cluster electron structure calculation, that the Hartree-Fock unlimited method accounts in a number of cases for an essential part of statistical correlation effects. The energy values and local characteristics of the [Ti 2 O 9 ] 12- cluster, calculated through the HF and MCSCF methods, are presented [ru
Approximate angular momentum projection from cranked intrinsic states
International Nuclear Information System (INIS)
Goodman, A.L.
1979-01-01
High-spin spectra are determined by approximately projecting states of good angular momentum from cranked Hartree-Fock-Bogoliubov (CHFB) wave functions. For each J the projected energy is E/sub PROJ/ approx. = E/sub CHFB/ - (ΔJ) 2 /2 J/sub CHFB/, where the moment of inertia J and the fluctuation ΔJ are spin dependent. For /sup 168,170/Yb and 174 Hf the projected J is less than the CHFB value for all J. Consequently approximate projection increases all yrast excitation energies for these nuclei
Energy Technology Data Exchange (ETDEWEB)
Bozkaya, Uğur, E-mail: ugur.bozkaya@atauni.edu.tr [Department of Chemistry, Atatürk University, Erzurum 25240, Turkey and Department of Chemistry, Middle East Technical University, Ankara 06800 (Turkey)
2014-09-28
General analytic gradient expressions (with the frozen-core approximation) are presented for density-fitted post-HF methods. An efficient implementation of frozen-core analytic gradients for the second-order Møller–Plesset perturbation theory (MP2) with the density-fitting (DF) approximation (applying to both reference and correlation energies), which is denoted as DF-MP2, is reported. The DF-MP2 method is applied to a set of alkanes, conjugated dienes, and noncovalent interaction complexes to compare the computational cost of single point analytic gradients with MP2 with the resolution of the identity approach (RI-MP2) [F. Weigend and M. Häser, Theor. Chem. Acc. 97, 331 (1997); R. A. Distasio, R. P. Steele, Y. M. Rhee, Y. Shao, and M. Head-Gordon, J. Comput. Chem. 28, 839 (2007)]. In the RI-MP2 method, the DF approach is used only for the correlation energy. Our results demonstrate that the DF-MP2 method substantially accelerate the RI-MP2 method for analytic gradient computations due to the reduced input/output (I/O) time. Because in the DF-MP2 method the DF approach is used for both reference and correlation energies, the storage of 4-index electron repulsion integrals (ERIs) are avoided, 3-index ERI tensors are employed instead. Further, as in case of integrals, our gradient equation is completely avoid construction or storage of the 4-index two-particle density matrix (TPDM), instead we use 2- and 3-index TPDMs. Hence, the I/O bottleneck of a gradient computation is significantly overcome. Therefore, the cost of the generalized-Fock matrix (GFM), TPDM, solution of Z-vector equations, the back transformation of TPDM, and integral derivatives are substantially reduced when the DF approach is used for the entire energy expression. Further application results show that the DF approach introduce negligible errors for closed-shell reaction energies and equilibrium bond lengths.
Angular-momentum-projected cranked HFB approach to the study of nuclear rotations
International Nuclear Information System (INIS)
Wuest, E.; Ansari, A.; Mosel, U.
1985-01-01
Employing a pairing-plus-quadrupole interaction hamiltonian and projecting out good angular momentum states from the cranked Hartree-Fock-Bogoliubov (CHFB) intrinsic wave functions the yrast spectra of 158 Dy and 168 Yb are calculated up to moderately high spins (Isub(max)=16) as to include the backbending region. Then the variation of pairing correlation, g-factor and rotational alignment of neutron spin as a function of total angular momentum is studied. The effect of particle number projection on the spin-projected CHFB wave functions is also investigated and is found to be unimportant for the calculation of g-factors. On the other hand, corrections of the excitation energies for number fluctuations in the CHFB wave functions are essential. Furthermore, looking at the distribution of the total projection quantum number K in various cranking wave functions we are able to throw some light on the Knot=0 nature of the aligned s-band. A variation-after-spin projection calculation strictly for the axial shape, without cranking, is also carried out for both the nuclei considered here. In the low-spin region this numerically 'cheaper' scheme produces energy spectra similar to that of the CHFB method, and may thus be used to readjust the interaction parameters. (orig.)
Microscopic analysis of angular momentum projected HFB-states in terms of interacting bosons
International Nuclear Information System (INIS)
Ring, P.; Pannert, W.
1984-12-01
Angular momentum- and number-projected Hartree-Fock-Bogoliubov (HFB) wavefunctions for transitional and deformed Rare Earth nuclei are analyzed in terms of Fermion pairs coupled to angular momenta L = 0(S), 2(D), 4(G), ... The Fermion space is truncated to contain only S-D or S-D-G pairs. The variation is carried out before and after angular momentum projection and with different truncations. The influence of the truncation on physical quantities such as moments of inertia, quadrupole moments or pair transfer matrix elements is discussed. 21 references
Spontaneous spin-polarization and phase transition in the relativistic approach
International Nuclear Information System (INIS)
Maruyama, Tomoyuki; Tatsumi, Toshitaka
2001-01-01
We study the spin-polarization mechanism in the highly dense nuclear matter with the relativistic mean-field approach. In the relativistic Hartree-Fock framework we find that there are two kinds of spin-spin interaction channels, which are the axial-vector and tensor exchange ones. If each interaction is strong and different sign, the system loses the spherical symmetry and holds the spin-polarization in the high-density region. When the axial-vector interaction is negative enough, the system holds ferromagnetism. (author)
Low-energy coupling of individual and collective degrees of freedom: a general microscopic approach
International Nuclear Information System (INIS)
Quentin, P.; Meyer, M.
1988-01-01
A general microscopic approach of low energy coupling of individual and collective degrees of freedom is presented. The ingredients of a Bohr-Mottelson unified model description are determined consistently from the Skyrme SIII effective interaction, through the adiabatic limit of the time-dependent Hartree-Fock-Bogoliubov approximation. Three specific aspects will be mostly developed: i) the effect of pairing correlations on adiabatic mass parameters and collective dynamics; ii) a consistent coupling of collective and individual degrees of freedom to describe odd nuclei; iii) a study of spectroscopic data in odd-odd nuclei as a test of effective nucleon-nucleon interactions. (author)
Energy Technology Data Exchange (ETDEWEB)
Granovsky, Alexander A., E-mail: alex.granovsky@gmail.com [Firefly project, Moscow, 117593 Moscow (Russian Federation)
2015-12-21
We present a new, very efficient semi-numerical approach for the computation of state-specific nuclear gradients of a generic state-averaged multi-configuration self consistent field wavefunction. Our approach eliminates the costly coupled-perturbed multi-configuration Hartree-Fock step as well as the associated integral transformation stage. The details of the implementation within the Firefly quantum chemistry package are discussed and several sample applications are given. The new approach is routinely applicable to geometry optimization of molecular systems with 1000+ basis functions using a standalone multi-core workstation.
International Nuclear Information System (INIS)
Granovsky, Alexander A.
2015-01-01
We present a new, very efficient semi-numerical approach for the computation of state-specific nuclear gradients of a generic state-averaged multi-configuration self consistent field wavefunction. Our approach eliminates the costly coupled-perturbed multi-configuration Hartree-Fock step as well as the associated integral transformation stage. The details of the implementation within the Firefly quantum chemistry package are discussed and several sample applications are given. The new approach is routinely applicable to geometry optimization of molecular systems with 1000+ basis functions using a standalone multi-core workstation
Granovsky, Alexander A
2015-12-21
We present a new, very efficient semi-numerical approach for the computation of state-specific nuclear gradients of a generic state-averaged multi-configuration self consistent field wavefunction. Our approach eliminates the costly coupled-perturbed multi-configuration Hartree-Fock step as well as the associated integral transformation stage. The details of the implementation within the Firefly quantum chemistry package are discussed and several sample applications are given. The new approach is routinely applicable to geometry optimization of molecular systems with 1000+ basis functions using a standalone multi-core workstation.
Relativistic approach to nuclear structure
International Nuclear Information System (INIS)
Nguyen Van Giai; Bouyssy, A.
1987-03-01
Some recent works related with relativistic models of nuclear structure are briefly reviewed. The Dirac-Hartree-Fock and Dirac-Brueckner-Hartree-Fock are recalled and illustrated by some examples. The problem of isoscalar current and magnetic moments of odd nuclei is discussed. The application of the relativistic model to the nuclear response function is examined
Managing projects using a project management approach
Directory of Open Access Journals (Sweden)
Marko D. Andrejić
2011-04-01
Full Text Available Modern management theory treats all complex tasks and duties like projects and make these projects possible to be managed by a particular organizational-management concept in order to achieve a goal effectively. A large number of jobs and tasks performed in the system of defense or for defense purposes have the characteristics of projects. Project management is both a skill and a science of monitoring human, material, financial, energy and other resources to achieve required objectives within the given limits: deadlines, time, budget, possibility of realization and the satisfaction of the interests of all project participants. Project management is a traditional area of applied (or functional management focused on managing complex and uncertain situations with defined goals. Introduction In conditions of rapid change and high uncertainty, only adaptive organizations survive, i. e. those that are able not only to react quickly to changes but also to proactively take advantage of changes. Development of project management The biggest influence on the development of the area had complex jobs within the engineering profession. In parallel with the traditional approach new approaches began to develop, while the traditional one still remained in use. Contrary to the traditional engineering approach, a dynamic model first developed in order to respond to demands for greater control of costs. Project management Project management is a skill and knowledge of human and material resources to achieve set objectives within prescribed limits: deadlines, time, budget, possibility of realization, and the satisfaction of all participants in the project. In order to realize a project effectively, it is necessary to manage it rationally. Planning and project management A project plan is a document that allows all team members insight on where to go, when to start and when to arrive, what is necessary to be done in order to achieve the project objectives and what
Green's functions in quantum chemistry II - Improving the Σ perturbation approach
International Nuclear Information System (INIS)
Sebastian, K.L.; Narayanan, P.; Rama Varma, K.T.
1978-01-01
Two methods, which are expected to lead to results better than those of the Σ perturbation approach given earlier are investigated. Within the algebraic approximation, the methods are applied to the hydrogen molecule and to ethylene in the Pariser-Parr-Pople (PPP) approximation. Both the methods are seen to suffer from the defect of not conserving the number of particles in the system. The methods are (a) the use of a partitioning other than Hartree-Fock. Due to the non-conservation of particle number, the method does not seem to be suited for the calculation of the ground state energy, but it gives good results for ionisation potentials. The investigation reveals that the only partitioning which conserves the number of particles is the Hartree-Fock partitioning (b) the renormalised Σ perturbation method, suggested by Csnak and others. For ethylene in the PPP approximation, the method does conserve the number of particles (but not in general). However, the energy obtained is not as good as that in the Σ perturbation method. This method therefore seems to be of limited applicability in molecular calculations. (author)
Four Approaches to Project Evaluation
DEFF Research Database (Denmark)
Laursen, Markus; Svejvig, Per; Rode, Anna Le Gerstrøm
. Each of the framework’s four approaches provides a distinct evaluation that sheds light on some issues while leaving others unattended. Following these lines, the paper calls for more multi-faceted project evaluations. Introducing a framework that can help analyze existing evaluations and structure......There are many theoretical and practical reasons for evaluating projects – including explorative arguments focusing on expanding descriptive knowledge on project work as well as normative arguments focusing on improving prescriptive models of project performance. Despite the need for project...... management methodologies that work and combat project failure, and research methods that can assess effective project management and methodologies, as well as empirical research on the actuality of projects as practice, evaluation research on projects including project management and methodologies is scarce...
PROJECT APPROACH TO ENERGY MANAGEMENT
Directory of Open Access Journals (Sweden)
Інга Борисівна СЕМКО
2016-02-01
Full Text Available Project management is widely used around the world as a tool to improve business performance. Correct implementation of the program of implementation of energy efficiency is accompanied by the adoption of an appropriate legislative framework, support programs, the approval of market-based instruments. Currently, it is paying enough attention to the effective application of market-based instruments, although most of the activities in the field of energy efficiency from the economic side are quite profitable. The authors suggested the use of the methodology of project management to the management of energy-saving measures, new approaches to the place and role of project management in the hierarchy of guidance. As a result, this innovation can improve the competitiveness of enterprises. The conclusions that the energy-saving project management allows you to get the best results for their implementation by reducing the time, resources, risk reduction.
Nuclear structure for the crust of neutron stars and exotic nuclei
International Nuclear Information System (INIS)
Goegelein, Peter
2007-01-01
In this work the Skyrme Hartree-Fock and Relativistic Hartree--Fock approaches have been considered to describe the structure of nuclear systems ranging from finite nuclei, structures in the crust of neutron stars to homogeneous matter. Effects of pairing correlations and finite temperature are also taken into account. The numerical procedure in the cubic box is described for the Skyrme Hartree-Fock as well as the relativistic Hartree-Fock approach. And finally, results for the crust of neutron stars and exotic nuclei are presented and discussed. (orig.)
Nuclear structure for the crust of neutron stars and exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Goegelein, Peter
2007-07-01
In this work the Skyrme Hartree-Fock and Relativistic Hartree--Fock approaches have been considered to describe the structure of nuclear systems ranging from finite nuclei, structures in the crust of neutron stars to homogeneous matter. Effects of pairing correlations and finite temperature are also taken into account. The numerical procedure in the cubic box is described for the Skyrme Hartree-Fock as well as the relativistic Hartree-Fock approach. And finally, results for the crust of neutron stars and exotic nuclei are presented and discussed. (orig.)
Nuclear Fermi Dynamics: physical content versus theoretical approach
International Nuclear Information System (INIS)
Griffin, J.J.
1977-01-01
Those qualitative properties of nuclei, and of their energetic collisions, which seem of most importance for the flow of nuclear matter are listed and briefly discussed. It is suggested that nuclear matter flow is novel among fluid dynamical problems. The name, Nuclear Fermi Dynamics, is proposed as an appropriate unambiguous label. The Principle of Commensurability, which suggests the measurement of the theoretical content of an approach against its expected predictive range is set forth and discussed. Several of the current approaches to the nuclear matter flow problem are listed and subjected to such a test. It is found that the Time-Dependent Hartree-Fock (TDHF) description, alone of all the major theoretical approaches currently in vogue, incorporates each of the major qualitative features within its very concise single mathematical assumption. Some limitations of the conventional TDHF method are noted, and one particular defect is discussed in detail: the Spurious Cross Channel Correlations which arise whenever several asymptotic reaction channels must be simultaneously described by a single determinant. A reformulated Time-Dependent-S-Matrix Hartree-Fock Theory is proposed, which obviates this difficulty. It is noted that the structure of TD-S-HF can be applied to a more general class of non-linear wave mechanical problems than simple TDHF. Physical requirements minimal to assure that TD-S-HF represents a sensible reaction theory are utilized to prescribe the definition of acceptable asymptotic channels. That definition, in turn, defines the physical range of the TD-S-HF theory as the description of collisions of certain mathematically well-defined objects of mixed quantal and classical character, the ''TDHF droplets.''
Further explorations of Skyrme-Hartree-Fock-Bogoliubov mass formulas. VIII. Role of Coulomb exchange
International Nuclear Information System (INIS)
Goriely, S.; Pearson, J. M.
2008-01-01
Following suggestions that the energy associated with Coulomb correlations and a possible charge-symmetry breaking of nuclear forces might largely cancel the Coulomb-exchange term, we refit the HFB-14 mass model without the Coulomb-exchange term to essentially all the mass data. The resulting mass model, HFB-15, gives a better fit to the 2149 mass data, σ rms falling from 0.729 to 0.678 MeV. The improvement in the energy differences between mirror nuclei is particularly striking: the Nolen-Schiffer anomaly, which is strong for HFB-14, is essentially eliminated. As for the extrapolation to highly neutron-rich nuclei, the HFB-15 model differs significantly from HFB-14, with up to 15 MeV less binding being predicted. However, the differences in the predicted values of differential quantities such as the neutron-separation energies, β-decay energies and fission barriers are very much smaller
Multiconfiguration Hartree--Fock method for atomic energy levels and transition probabilities
International Nuclear Information System (INIS)
Fischer, C.F.
1978-01-01
The effect of correlation in the motion of electrons in a many-electron system is considered in the theoretical determination of atomic properties. The correlation effects are computed using the configuration interaction. Restriction is made to the discussion of outer processes of neutral atoms or ions of low degree of ionization in which the relativistic effects are small. The first-order theory, the 3p,3d state of Al II, correlation in the 3d/sup n/ shell, and f-values in the presence of cross-overs are discussed. 29 references
Instability of the cranked Hartree-Fock-Bogoliubov field in backbending region
International Nuclear Information System (INIS)
Horibata, Takatoshi; Onishi, Naoki.
1981-07-01
The stability condition of the cranked HFB field is examined explicitly by solving the eigen value equation for the second order variation of the energy, which is reduced to an algebraic equation through a coupled dispersion formula. We confirm that the HFB field is unstable in the backbending region of irregular rotational band, even though the frequency of the softest RPA mode stays in positive value. We investigate properties of the softest mode in detail. (author)
Multiconfiguration hartree-fock theory for pseudorelativistic systems: The time-dependent case
Hajaiej, Hichem; Markowich, Peter A.; Trabelsi, Saber
2014-01-01
to the underlying system under technical assumptions on the energy of the initial data and the charge of the nucleus. Moreover, we prove that the result can be extended to the case of neutron stars when the number of electrons is less than a critical number N cr
The positronium and the dipositronium in a Hartree-Fock approximation of quantum electrodynamics
Sok, Jérémy
2016-02-01
The Bogoliubov-Dirac-Fock (BDF) model is a no-photon approximation of quantum electrodynamics. It allows to study relativistic electrons in interaction with the Dirac sea. A state is fully characterized by its one-body density matrix, an infinite rank non-negative projector. We prove the existence of the para-positronium, the bound state of an electron and a positron with antiparallel spins, in the BDF model represented by a critical point of the energy functional in the absence of an external field. We also prove the existence of the dipositronium, a molecule made of two electrons and two positrons that also appears as a critical point. More generally, for any half integer j ∈ 1/2 + Z + , we prove the existence of a critical point of the energy functional made of 2j + 1 electrons and 2j + 1 positrons.
Elastic and inelastic form factors of the Ne20 in the Hartree-Fock approximation
International Nuclear Information System (INIS)
Oliveira, S.A.C. de.
1977-01-01
Properties of Ne 20 fundamental band are studied such as particle densities and elastic and inelastic form factors. A two body interaction is used and its matrix elements involve only the independent particle states of the 1s-0d shell [pt
The positronium and the dipositronium in a Hartree-Fock approximation of quantum electrodynamics
DEFF Research Database (Denmark)
Sok, Jérémy Vithya
2016-01-01
The Bogoliubov-Dirac-Fock (BDF) model is a no-photon approximation of quantum electrodynamics. It allows to study relativistic electrons in interaction with the Dirac sea. A state is fully characterized by its one-body density matrix, an infinite rank non-negative projector. We prove the existence...
Energy Technology Data Exchange (ETDEWEB)
Dupuis, M. (ed.)
1981-02-01
Twenty-seven papers are included in four sessions titled: generalized Fock operator methods, annihilation of single excitations methods, second-order MCSCF methods, and applications of MCHF methods. Separate abstracts were prepared for eight papers; one of the remaining had been previously abstracted. (DLC)
Exact norm-conserving stochastic time-dependent Hartree-Fock
International Nuclear Information System (INIS)
Tessieri, Luca; Wilkie, Joshua; Cetinbas, Murat
2005-01-01
We derive an exact single-body decomposition of the time-dependent Schroedinger equation for N pairwise interacting fermions. Each fermion obeys a stochastic time-dependent norm-preserving wave equation. As a first test of the method, we calculate the low energy spectrum of helium. An extension of the method to bosons is outlined
Etude hartree-fock de la tautomerisation du 1azirene sous pression ...
African Journals Online (AJOL)
The lazirene molecule is a heterocyclic compound containing two carbon atoms, one nitrogen atom and three hydrogen atoms which one is on the nitrogen atom. The hydrogen pressure being represented by one molecule of dihydrogen, the reaction of the dihydrogen with the azirene in the presence of the palladium ...
Hartree-Fock and density functional theory study of alpha-cyclodextrin conformers.
Jiménez, Verónica; Alderete, Joel B
2008-01-31
Herein, we report the geometry optimization of four conformers of alpha-cyclodextrin (alpha-CD) by means of PM3, HF/STO-3G, HF/3-21G, HF/6-31G(d), B3LYP/6-31G(d), and X3LYP/6-31G(d) calculations. The analysis of several geometrical parameters indicates that all conformers possess bond lengths, angles, and dihedrals that agree fairly well with the crystalline structure of alpha-CD. However, only three of them (1-3) resemble the polar character of CDs and show intramolecular hydrogen-bonding patterns that agree with experimental NMR data. Among them, conformer 3 appears to be the most stable species both in the gas phase and in solution; therefore, it is expected to be the most suitable representative structure for alpha-CD conformation. The purpose of selecting such a species is to identify an appropriate structure to be employed as a starting point for reliable computational studies on complexation phenomena. Our results indicate that the choice of a particular alpha-CD conformer should affect the results of ab initio computational studies on the inclusion complexation with this cyclodextrin since both the direction and the magnitude of the dipole moment depend strongly on the conformation of alpha-CD.
Hartree Fock-type equations in relativistic quantum electrodynamics with non-linear gauge fixing
International Nuclear Information System (INIS)
Dietz, K.; Hess, B.A.
1990-08-01
Relativistic mean-field equations are obtained by minimizing the effective energy obtained from the gauge-invariant energy density by eliminating electro-magnetic degrees of freedom in certain characteristic non-linear gauges. It is shown that by an appropriate choice of gauge many-body correlations, e.g. screening, three-body 'forces' etc. can be included already at the mean-field level. The many-body perturbation theory built on the latter is then expected to show improved 'convergence'. (orig.)
The calculation of collective energies from periodic time-dependent Hartree-Fock solutions
International Nuclear Information System (INIS)
Zahed, I.; Baranger, M.
1983-06-01
A periodic TDHF solution is used as the reference state for a diagrammatic expansion of the propagator. A discrete Fourier transform leads to a function of energy, whose poles are the corresponding energy levels. Limiting the expansion to first-order diagrams leads to a new derivation of the Bohr-Sommerfeld-like quantization rule for collective states
Hartree-Fock calculations for strongly deformed and highly excited nuclei using the Skyrme force
International Nuclear Information System (INIS)
Zint, P.G.
1975-01-01
It has been shown that in CHF-calculations the Skyrme-force is usefull to describe strongly deformed nuclei with even proton and neutron number till separation. Thereby the eigenfunctions of the two-centre Hamiltonian form an adequate basis. With this procedure, we obtain the correct deformation of the 32 S-system. Induding the spurious energy of relative motion between the 16 O-fragments, the energy curve is a good approximation for the real potential, extracted form scattering experiments. (orig./WL) [de
International Nuclear Information System (INIS)
Dupuis, M.
1981-02-01
Twenty-seven papers are included in four sessions titled: generalized Fock operator methods, annihilation of single excitations methods, second-order MCSCF methods, and applications of MCHF methods. Separate abstracts were prepared for eight papers; one of the remaining had been previously abstracted
Λ hypernuclei in the Skyrme-Hartree-Fock treatment with G-matrix motivated interactions
International Nuclear Information System (INIS)
Lanskoy, D.E.; Yamamoto, Y.
1997-01-01
Skyrme-like hyperon-nucleon potentials are derived from G-matrix calculations and shown to reproduce well the Λ single-particle spectra of hypernuclei measured in BNL and KEK. Fit of the spectra can restrict p-wave ΛN interaction, radii of Λ orbits in hypernuclear ground states, Λ well depth and effective mass in nuclear matter rather tightly. Implications of ΛN spin-orbit force to the spectra are considered. (author)
QCD-based relativistic Hartree-Fock calculations for identical quarks
International Nuclear Information System (INIS)
Dey, J.; Dey, M.; Le Tourneux, J.
1985-12-01
As was first pointed out by Witten, large number of colours (Nsub(c)) leads to a simplification in the theory of baryon masses in that the quarks may be assumed to move in a mean field which can be found self-consistently. The interquark potential in such a description can be borrowed from the meson sector phenomenology in the absence of an accurate evaluation of it from large Nsub(c) quantum chromodynamics (QCD). We have carried out this program with such a potential due to Richardson, used often by workers in the meson sector. This potential has the advantage of incorporating the two main features of QCD, namely confinement and asymptotic freedom. In view of the small number of parameters involved, the results agree surprisingly well with experiment for the case of three identical quarks. (author)
Meson dynamics and the nuclear many-body problem. II. Finite density Hartree-Fock
International Nuclear Information System (INIS)
Wilets, L.; Puff, R.D.; Chiang, D.; Nutt, W.T.
1976-01-01
The field-theoretic many-nucleon problem is formulated, and an analysis which sums all ''uncrossed meson line'' diagrams is investigated in detail. The calculation of energy per nucleon, after proper identification of infinite mass renormalization terms, exhibits effects of nuclear recoil, relativistic kinematics, and retardation. Numerical results are presented for π and ω mesons, and the nucleon interaction energies obtained are compared with the traditional static limit of infinite nucleon mass
Zeroth order regular approximation approach to electric dipole moment interactions of the electron
Gaul, Konstantin; Berger, Robert
2017-07-01
A quasi-relativistic two-component approach for an efficient calculation of P ,T -odd interactions caused by a permanent electric dipole moment of the electron (eEDM) is presented. The approach uses a (two-component) complex generalized Hartree-Fock and a complex generalized Kohn-Sham scheme within the zeroth order regular approximation. In applications to select heavy-elemental polar diatomic molecular radicals, which are promising candidates for an eEDM experiment, the method is compared to relativistic four-component electron-correlation calculations and confirms values for the effective electric field acting on the unpaired electron for RaF, BaF, YbF, and HgF. The calculations show that purely relativistic effects, involving only the lower component of the Dirac bi-spinor, are well described by treating only the upper component explicitly.
Managing projects a team-based approach
Brown, Karen A
2010-01-01
Students today are likely to be assigned to project teams or to be project managers almost immediately in their first job. Managing Projects: A Team-Based Approach was written for a wide range of stakeholders, including project managers, project team members, support personnel, functional mangers who provide resources for projects, project customers (and customer representatives), project sponsors, project subcontractors, and anyone who plays a role in the project delivery process. The need for project management is on the rise as product life cycles compress, demand for IT systems increases, and business takes on an increasingly global character. This book adds to the project management knowledge base in a way that fills an unmet need—it shows how teams can apply many of the standard project management tools, as well as several tools that are relatively new to the field. Managing Projects: A Team-Based Approach offers the academic rigor found in most textbooks along with the practical attributes often foun...
Self-consistent RPA and the time-dependent density matrix approach
Energy Technology Data Exchange (ETDEWEB)
Schuck, P. [Institut de Physique Nucleaire, Orsay (France); CNRS et Universite Joseph Fourier, Laboratoire de Physique et Modelisation des Milieux Condenses, Grenoble (France); Tohyama, M. [Kyorin University School of Medicine, Mitaka, Tokyo (Japan)
2016-10-15
The time-dependent density matrix (TDDM) or BBGKY (Bogoliubov, Born, Green, Kirkwood, Yvon) approach is decoupled and closed at the three-body level in finding a natural representation of the latter in terms of a quadratic form of two-body correlation functions. In the small amplitude limit an extended RPA coupled to an also extended second RPA is obtained. Since including two-body correlations means that the ground state cannot be a Hartree-Fock state, naturally the corresponding RPA is upgraded to Self-Consistent RPA (SCRPA) which was introduced independently earlier and which is built on a correlated ground state. SCRPA conserves all the properties of standard RPA. Applications to the exactly solvable Lipkin and the 1D Hubbard models show good performances of SCRPA and TDDM. (orig.)
International Nuclear Information System (INIS)
Yonemitsu, K.; Bishop, A.R.
1992-01-01
As a convenient qualitative approach to strongly correlated electronic systems, an inhomogeneous Hartree-Fock plus random-phase approximation is applied to response functions for the two-dimensional multiband Hubbard model for cuprate superconductors. A comparison of the results with those obtained by exact diagonalization by Wagner, Hanke, and Scalapino [Phys. Rev. B 43, 10 517 (1991)] shows that overall structures in optical and magnetic particle-hole excitation spectra are well reproduced by this method. This approach is computationally simple, retains conceptual clarity, and can be calibrated by comparison with exact results on small systems. Most importantly, it is easily extended to larger systems and straightforward to incorporate additional terms in the Hamiltonian, such as electron-phonon interactions, which may play a crucial role in high-temperature superconductivity
Mechanism of equalization of proton and neutron radii and the Coulomb anomaly
International Nuclear Information System (INIS)
Caurier, E.; Poves, A.; Zuker, A.
1980-01-01
It is shown that a one parameter modification of the effective forces allows to resolve the Coulomb energy anomalies in the Ca region within the framework of Hartree Fock (HF) and isospin projected Hartree Fock (IPHF) theories. A simple microscopic mechanism of equalization of neutron and proton radii is invoked to produce results consistent with available data
Equations-of-motion approach to a quantum theory of large-amplitude collective motion
International Nuclear Information System (INIS)
Klein, A.
1984-01-01
The equations-of-motion approach to large-amplitude collective motion is implemented both for systems of coupled bosons, also studied in a previous paper, and for systems of coupled fermions. For the fermion case, the underlying formulation is that provided by the generalized Hartree-Fock approximation (or generalized density matrix method). To obtain results valid in the semi-classical limit, as in most previous work, we compute the Wigner transform of quantum matrices in the representation in which collective coordinates are diagonal and keep only the leading contributions. Higher-order contributions can be retained, however, and, in any case, there is no ambiguity of requantization. The semi-classical limit is seen to comprise the dynamics of time-dependent Hartree-Fock theory (TDHF) and a classical canonicity condition. By utilizing a well-known parametrization of the manifold of Slater determinants in terms of classical canonical variables, we are able to derive and understand the equations of the adiabatic limit in full parallelism with the boson case. As in the previous paper, we can thus show: (i) to zero and first order in the adiabatic limit the physics is contained in Villar's equations; (ii) to second order there is consistency and no new conditions. The structure of the solution space (discussed thoroughly in the previous paper) is summarized. A discussion of associated variational principles is given. A form of the theory equivalent to self-consistent cranking is described. A method of solution is illustrated by working out several elementary examples. The relationship to previsous work, especially that of Zelevinsky and Marumori and coworkers is discussed briefly. Three appendices deal respectively with the equations-of-motion method, with useful properties of Slater determinants, and with some technical details associated with the fermion equations of motion. (orig.)
Systems approach to project risk management
Energy Technology Data Exchange (ETDEWEB)
Kindinger, J. P. (John P.)
2002-01-01
This paper describes the need for better performance in the planning and execution of projects and examines the capabilities of two different project risk analysis methods for improving project performance. A quantitative approach based on concepts and tools adopted from the disciplines of systems analysis, probabilistic risk analysis, and other fields is advocated for managing risk in large and complex research & development projects. This paper also provides an overview of how this system analysis approach for project risk management is being used at Los Alamos National Laboratory along with examples of quantitative risk analysis results and their application to improve project performance.
Energy Technology Data Exchange (ETDEWEB)
Koh, Meng-Hock [Universiti Teknologi Malaysia, Skudai, Johor (Malaysia); Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France); Duc, Dao Duy [Ton Duc Thang University, Division of Nuclear Physics, Ho Chi Minh City (Viet Nam); Ton Duc Thang University, Faculty of Applied Sciences, Ho Chi Minh City (Viet Nam); Nhan Hao, T.V. [Duy Tan University, Center of Research and Development, Danang (Viet Nam); Hue University, Center for Theoretical and Computational Physics, College of Education, Hue City (Viet Nam); Long, Ha Thuy [Hanoi University of Sciences, Vietnam National University, Hanoi (Viet Nam); Quentin, P. [Universiti Teknologi Malaysia, Skudai, Johor (Malaysia); Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France); Ton Duc Thang University, Division of Nuclear Physics, Ho Chi Minh City (Viet Nam); Bonneau, L. [Univ. Bordeaux, CENBG, UMR5797, Gradignan (France); CNRS, IN2P3, CENBG, UMR5797, Gradignan (France)
2016-01-15
In four well-deformed heavy odd nuclei, the energies of low-lying rotational band heads have been determined microscopically within a self-consistent Hartree-Fock-plus-BCS approach with blocking. A Skyrme nucleon-nucleon effective interaction has been used together with a seniority force to describe pairing correlations. Only such states which are phenomenologically deemed to be related to single-particle excitations have been considered. The polarization effects, including those associated with the genuine time-reversal symmetry breaking have been fully taken into account within our model assumptions. The calculated spectra are in reasonably good qualitative agreement with available data for the considered odd-neutron nuclei. This is not so much the case for the odd-proton nuclei. A potential explanation for such a difference in behavior is proposed. (orig.)
Project approach helps technology transfer
International Nuclear Information System (INIS)
Walcher, M.W.
1982-01-01
The placing of the contract by the National Power Corporation with Westinghouse for the Philippines nuclear power plant (PNPP-1) is described. Maximised use of Philippine contractors under Westinghouse supervision was provided for. Technology transfer is an important benefit of the contract arrangements, since National Power Corporation project management acquires considerable nuclear plant experience during plant construction through consultation with technical personnel. (U.K.)
The Japanese approach to financing LNG projects
International Nuclear Information System (INIS)
Aoki, Wataru
1995-01-01
The Japanese approach approach to financing LNG project has been what could be called a combined purchase and finance system which has been arranged mainly at the initiative of japan's Sogo Shosh (general trading companies) with the support of japanese governmental financial agencies and a purchase commitment from japanese utilities. In the QATARGAS project, despite it being the first greenfield LNG project in decade since North West Shelf Australia LNG project, financing for the LNG plant phase has been successfully arranged through Japanese financing. The structuring of the financial facilities for the QATARGAS project seems to have lessons for future development of the next generation of greenfield LNG projects. Discharge of the parties' liability, proper sharing of the risk burden and reconfirmation of the spirit of mutual understanding and trust among the parties concerned are key factors for the success of any new LNG project in the future. (Author)
How the Project Approach Challenges Young Children
Burns, Marcia V.; Lewis, Alisha L.
2016-01-01
In this article, educators at University Primary School in Champaign, Illinois, share examples and understandings of the ways The Project Approach challenges young children to think critically about topics of importance in their world. Project investigations that provoke academic and social challenges for individuals and classroom communities of…
International Nuclear Information System (INIS)
Petrovici, A.; Schmid, K.W.; Faessler, A.; Baktash, C.; Shashi, P.
1999-01-01
For a unified description of the structure of medium mass proton-rich nuclei at low as well as high angular momenta we used the complex version of the Excited Vampir approach. We employed chains of variational calculations based on symmetry-projected essentially complex Hartree-Fock-Bogoliubov (HFB) vacua which include neutron-proton pairing and unnatural-parity correlations. Since the Vampir approaches allow the use of rather large model spaces and of general two-body interactions, large-scale nuclear structure studies going far beyond the abilities of the conventional shell-model configuration-mixing approach are possible. Furthermore, since these approaches provide detailed spectroscopic information for the lowest few states for each spin and parity, they also have considerable advantages with respect to the shell-model Monte Carlo method in which only expectation values of operators in the thermodynamic ensembles or the ground state can be calculated. Our previous investigations on microscopic aspects of shape coexistence in N∼Z nuclei in the A∼70 mass region indicated the presence of a strong competition between particular configurations based on large and small oblate and prolate quadrupole deformations. Furthermore, since in N = Z nuclei neutrons and protons fill the same single particle orbits, the isovector neutron-proton and the like-nucleon pairing correlations were found to be strongly competitive in even-even systems. In addition, the neutron and proton alignments with increasing angular momentum occur simultaneously in these nuclei. On the other hand the theoretical results suggest that certain properties of these nuclei are extremely sensitive to small variations of particular parts of the effective Hamiltonian. Thus, our results indicate that the oblate-prolate coexistence and mixing at low spins depend on the strengths of the neutron-proton T = 0 matrix elements involving nucleons occupying f 5/2 (f 7/2 ) and g 9/2 single particle orbits
Project Management Approaches for Online Learning Design
Eby, Gulsun; Yuzer, T. Volkan
2013-01-01
Developments in online learning and its design are areas that continue to grow in order to enhance students' learning environments and experiences. However, in the implementation of new technologies, the importance of properly and fairly overseeing these courses is often undervalued. "Project Management Approaches for Online Learning Design"…
Symplectic manifolds, coadjoint orbits, and Mean Field Theory
International Nuclear Information System (INIS)
Rosensteel, G.
1986-01-01
Mean field theory is given a geometrical interpretation as a Hamiltonian dynamical system. The Hartree-Fock phase space is the Grassmann manifold, a symplectic submanifold of the projective space of the full many-fermion Hilbert space. The integral curves of the Hartree-Fock vector field are the time-dependent Hartree-Fock solutions, while the critical points of the energy function are the time-independent states. The mean field theory is generalized beyond determinants to coadjoint orbit spaces of the unitary group; the Grassmann variety is the minimal coadjoint orbit
APPROACHES FOR EVALUATING AND FINANCING INVESTMENT PROJECTS
Directory of Open Access Journals (Sweden)
MARIA-LOREDANA POPESCU
2011-04-01
Full Text Available This article presents the financial investment approach and the investment evaluation methods, which are criteria for assessing both investment projects and their funding sources. An important role in the analysis carried out is played by the investment decision and financing decision quality. Making an investment decision implies computing the related investment efficiency indicators. They allow the comparison of several variants of the same investment project as well as their comparison with other projects in the same industry or in other industries. The financing decision concerns the selection between their own sources (share capital, depreciation fund, profits, reserve funds, additional capital, revenues from investments, attracted sources (domestic resource mobilization and borrowed sources (credits.
Energy Technology Data Exchange (ETDEWEB)
Wahlen-Strothman, J. M. [Rice Univ., Houston, TX (United States); Henderson, T. H. [Rice Univ., Houston, TX (United States); Hermes, M. R. [Rice Univ., Houston, TX (United States); Degroote, M. [Rice Univ., Houston, TX (United States); Qiu, Y. [Rice Univ., Houston, TX (United States); Zhao, J. [Rice Univ., Houston, TX (United States); Dukelsky, J. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia; Scuseria, G. E. [Rice Univ., Houston, TX (United States)
2018-01-03
Coupled cluster and symmetry projected Hartree-Fock are two central paradigms in electronic structure theory. However, they are very different. Single reference coupled cluster is highly successful for treating weakly correlated systems, but fails under strong correlation unless one sacrifices good quantum numbers and works with broken-symmetry wave functions, which is unphysical for finite systems. Symmetry projection is effective for the treatment of strong correlation at the mean-field level through multireference non-orthogonal configuration interaction wavefunctions, but unlike coupled cluster, it is neither size extensive nor ideal for treating dynamic correlation. We here examine different scenarios for merging these two dissimilar theories. We carry out this exercise over the integrable Lipkin model Hamiltonian, which despite its simplicity, encompasses non-trivial physics for degenerate systems and can be solved via diagonalization for a very large number of particles. We show how symmetry projection and coupled cluster doubles individually fail in different correlation limits, whereas models that merge these two theories are highly successful over the entire phase diagram. Despite the simplicity of the Lipkin Hamiltonian, the lessons learned in this work will be useful for building an ab initio symmetry projected coupled cluster theory that we expect to be accurate in the weakly and strongly correlated limits, as well as the recoupling regime.
International Nuclear Information System (INIS)
Hayhurst, T.L.
1980-01-01
Techniques for applying ab-initio calculations to the analysis of atomic spectra are investigated, along with the relationship between the semi-empirical and ab-initio forms of Slater-Condon theory. Slater-Condon theory is reviewed with a focus on the essential features that lead to the effective Hamiltonians associated with the semi-empirical form of the theory. Ab-initio spectroscopic parameters are calculated from wavefunctions obtained via self-consistent field methods, while multiconfiguration Hamiltonian matrices are constructed and diagonalized with computer codes written by Robert Cowan of Los Alamos Scientific Laboratory. Group theoretical analysis demonstrates that wavefunctions more general than Slater determinants (i.e. wavefunctions with radical correlations between electrons) lead to essentially the same parameterization of effective Hamiltonians. In the spirit of this analysis, a strategy is developed for adjusting ab-initio values of the spectroscopic parameters, reproducing parameters obtained by fitting the corresponding effective Hamiltonian. Secondary parameters are used to screen the calculated (primary) spectroscopic parameters, their values determined by least squares. Extrapolations of the secondary parameters determined from analyzed spectra are attempted to correct calculations of atoms and ions without experimental levels. The adjustment strategy and extrapolations are tested on the KI sequence from K 0+ through Fe 7+ , fitting to experimental levels for V 4+ , and Cr 5+ ; unobserved levels and spectra are predicted for several members of the sequence. A related problem is also discussed: Energy levels of the Uranium hexahalide complexes, (UX 6 ) 2- for X = F, Cl, Br, and I, are fit to an effective Hamiltonian (the f 2 configuration in O/sub h/ symmetry) with corrections proposed by Brian Judd
Adachi, H; Kawai, J
2006-01-01
Molecular-orbital calculations for materials design such as alloys, ceramics, and coordination compounds are now possible for experimentalists. Molecuar-orbital calculations for the interpretation of chemical effect of spectra are also possible for experimentalists. The most suitable molecular-orbital calculation method for these purpose is the DV-Xa method, which is robust in such a way that the calculation converges to a result even if the structure of the molecule or solid is impossible in the pressure and temperature ranges on earth. This book specially addresses the methods to design novel materials and to predict the spectralline shape of unknown materials using the DV-Xa molecular-orbital method, but is also useful for those who want to calculate electronic structures of materials using any kind of method.
International Nuclear Information System (INIS)
Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.; Kan, K.K.
1979-01-01
It is suggested that the TDHF method be viewed, not as an approximation to but as a model of the exact Schroedinger system; that is, as a gedanken many-body experiment whose analysis with digital computers provides data worthy in itself of theoretical study. From such a viewpoint attention is focused on the structural analogies of the TDHF system with the exact theory rather than upon its quantitative equivalence, and the TDHF many-body system is studied as a challenge of its own which, although much simpler than the realistic problem, may still offer complexity enough to educate theorists in the present state of knowledge. In this spirit, the TDHF description of continuum reactions can be restructured from an initial-value problem into a form analogous to the S-matrix version of the Schroedinger theory. The resulting TD-S-HF theory involves only self-consistent single determinantal solutions of the TDHF equations and invokes time averaging to obtain a consistent interpretation of the TDHF analogs of quantities which are constant in the exact theory, such as the S-matrix and the asymptotic reaction channel characteristics. Periodic solutions then play the role of stationary eigenstates in the construction of suitable asymptotic reaction channels. If these periodic channel states occur only at discrete energies, then the resulting channels are mutually orthogonal (on the time average) and the theory exhibits a structure fully analogous to the exact theory. In certain special cases where the periodic solutions are known to occur as an energy continuum, the requirement that the periodicity of the channel solutions be gauge invariant provides a natural requantization condition which (suggestively) turns out to be identical with the Bohr-Sommerfeld quantization rule. 11 references
International Nuclear Information System (INIS)
Becker, R.L.; Svenne, J.P.
1975-12-01
Energy levels of states connected by a symmetry of the Hamiltonian normally should be degenerate. In self-consistent field theories, when only one of a pair of single-particle levels connected by a symmetry of the full Hamiltonian is occupied, the degeneracy is split and the unoccupied level often lies below the occupied one. Inversions of neutron-proton (charge) and time-reversal doublets in odd nuclei, charge doublets in even nuclei with a neutron excess, and spin-orbit doublets in spherical configurations with spin-unsaturated shells are examined. The origin of the level inversion is investigated, and the following explanation offered. Unoccupied single-particle levels, from a calculation in an A-particle system, should be interpreted as levels of the (A + 1)-particle system. When the symmetry-related level, occupied in the A-particle system, is also calculated in the (A + 1)-particle system it is degenerate with or lies lower than the other. That is, when both levels are calculated in the (A + 1)-particle system, they are not inverted. It is demonstrated that the usual prescription to occupy the lowest-lying orbitals should be modified to refer to the single-particle energies calculated in the (A + 1)- or the (A - 1)-particle system. This observation is shown to provide a justification for avoiding an oscillation of occupancy between symmetry-related partners in successive iterations leading to a self-consistency. It is pointed out that two degenerate determinants arise from occupying one or the other partner of an initially degenerate pair of levels and then iterating to self-consistency. The existence of the degenerate determinants indicates the need for introducing correlations, either by mixing the two configurations or by allowing additional symmetry-breaking (resulting in a more highly deformed non-degenerate configuration). 2 figures, 3 tables, 43 references
International Nuclear Information System (INIS)
Hayhurst, T.L.
1980-05-01
Techniques for applying ab-initio calculations to the analysis of atomic spectra are investigated, along with the relationship between the semi-empirical and ab-initio forms of Slater-Condon theory. Slater-Condon theory is reviewed with a focus on the essential features that lead to the effective Hamiltonians associated with the semi-empirical form of the theory. Ab-initio spectroscopic parameters are calculated from wavefunctions obtained via self-consistent field methods, while multi-configuration Hamiltonian matrices are constructed and diagonalized with computer codes written by Robert Cowan of Los Alamos Scientific Laboratory. Group theoretical analysis demonstrates that wavefunctions more general than Slater determinants (i.e., wavefunctions with radial correlations between electrons) lead to essentially the same parameterization of effective Hamiltonians. In the spirit of this analysis, a strategy is developed for adjusting ab-initio values of the spectroscopic parameters, reproducing parameters obtained by fitting the corresponding effective Hamiltonian. Secondary parameters are used to screen the calculated (primary) spectroscopic parameters, their values determined by least squares. Extrapolations of the secondary parameters determined from analyzed spectra are attempted to correct calculations of atoms and ions without experimental levels. The adjustment strategy and extrapolations are tested on the K I sequence from K 0+ through Fe 7+ , fitting to experimental levels for V 4+ , and Cr 5+ ; unobserved levels and spectra are predicted for several members of the sequence. A related problem is also discussed: energy levels of the uranium hexahalide complexes, (UX 6 ) 2- for X = F, Cl, Br, and I, are fit to an effective Hamiltonian (the f 2 configuration in O/sub h/ symmetry) with corrections proposed by Brian Judd
Hydrologic site characterization - the UMTRA project approach
International Nuclear Information System (INIS)
Binkman, J.E.; Hoopes, J.R.
1985-01-01
The United States Environmental Protection Agency (EPA) Standards (40 CFR 192) require site characterization of the hydrogeologic regime at and around each Uranium Mill Tailings Remedial Action (UMTRA) Project site. Also, ''judgements on the possible need for remedial or protective actions for groundwater aquifers should be guided by relevant considerations described in EPA's hazardous waste management system (47 CFR 32274).'' To address those two sets of rules and regulations, a generic approach is being developed. Fourteen primary issues were determined. These issues can be grouped into those that can be determined by documentation of available information and present conditions, those that require extensive field investigations and those that require some form of predictive modeling. To address the various issues requires an integrated effort of hydrogeologists, environmental engineers or scientists and health physicists. In this paper, the approach to the resolution of these fourteen issues is described briefly
Quantum canonical ensemble: A projection operator approach
Magnus, Wim; Lemmens, Lucien; Brosens, Fons
2017-09-01
Knowing the exact number of particles N, and taking this knowledge into account, the quantum canonical ensemble imposes a constraint on the occupation number operators. The constraint particularly hampers the systematic calculation of the partition function and any relevant thermodynamic expectation value for arbitrary but fixed N. On the other hand, fixing only the average number of particles, one may remove the above constraint and simply factorize the traces in Fock space into traces over single-particle states. As is well known, that would be the strategy of the grand-canonical ensemble which, however, comes with an additional Lagrange multiplier to impose the average number of particles. The appearance of this multiplier can be avoided by invoking a projection operator that enables a constraint-free computation of the partition function and its derived quantities in the canonical ensemble, at the price of an angular or contour integration. Introduced in the recent past to handle various issues related to particle-number projected statistics, the projection operator approach proves beneficial to a wide variety of problems in condensed matter physics for which the canonical ensemble offers a natural and appropriate environment. In this light, we present a systematic treatment of the canonical ensemble that embeds the projection operator into the formalism of second quantization while explicitly fixing N, the very number of particles rather than the average. Being applicable to both bosonic and fermionic systems in arbitrary dimensions, transparent integral representations are provided for the partition function ZN and the Helmholtz free energy FN as well as for two- and four-point correlation functions. The chemical potential is not a Lagrange multiplier regulating the average particle number but can be extracted from FN+1 -FN, as illustrated for a two-dimensional fermion gas.
Comparisons on International Approaches of Business and Project Risk Management
Nadia Carmen ENE
2005-01-01
In this article we intend to present a comparative approach between three recognized international methodologies for risk management: RISKMAN, Project Management Institute Methodology-PMBoK and Project Risk Analysis and Management Guide (produced by Association for Project Management).
An Approach for Implementation of Project Management Information Systems
Běrziša, Solvita; Grabis, Jānis
Project management is governed by project management methodologies, standards, and other regulatory requirements. This chapter proposes an approach for implementing and configuring project management information systems according to requirements defined by these methodologies. The approach uses a project management specification framework to describe project management methodologies in a standardized manner. This specification is used to automatically configure the project management information system by applying appropriate transformation mechanisms. Development of the standardized framework is based on analysis of typical project management concepts and process and existing XML-based representations of project management. A demonstration example of project management information system's configuration is provided.
Nuclear outages: an approach to project controls
International Nuclear Information System (INIS)
Bryson, R.
1985-01-01
The annual budget for maintaining and operating a nuclear power plant has risen dramatically over the past 5 years. NRC-mandated plant improvements and outage related expenses are often cited to be the main contributors to these escalating budgets. Nuclear utilities have responded by developing programs to improve plant availability and outage costs through improved outage performance. Utilities recognize that for capital improvements the program to control costs does no begin with outage planning, but rather more appropriately up front during the engineering phase. To support their management objectives, utilities have been developing comprehensive project control systems for concurrently reducing capital expenditures, outage-related costs, and time. This paper provides an approach to project controls that, rather than using one all inclusive comprehensive system, requires five separate monitoring systems - one for each phase of an activity's life cycle. Through the integration of these discrete but interrelated systems, utility management acquires the necessary tools for comprehensive planning and control of their modification program and effective detailed monitoring for all outage-related activities
Project evaluation: one framework - four approaches
DEFF Research Database (Denmark)
Rode, Anna Le Gerstrøm; Svejvig, Per
. Introducing a framework that can help structure such evaluations, the aim of this paper is to contribute to project theory and practice by inspiring project researchers and aiding project workers in their efforts to open up the black box of projects and deliver relevant and valuable results......There are many theoretical and practical reasons for evaluating projects – including explorative arguments focusing on expanding descriptive knowledge on projects as well as normative arguments focusing on developing prescriptive knowledge of project management. Despite the need for effective...... project management and research methods that can assess effective project management methodologies, extant literature on evaluation procedures or guidelines on how to evaluate projects and/or project management is scarce. To address this challenge, this paper introduces an evaluation framework consisting...
Trevino Project: a fast-track approach for a small construction project
International Nuclear Information System (INIS)
Schick, C.J.; Lynn, N.S.
1982-01-01
The approach to a construction project can vary according to the size, location, and degree of difficulty associated with the project. This paper deals with one approach that can be taken to a small construction project, the fast-track approach. A small construction project can be defined as a project having less than $20 million capital cost or a project with a low degree of difficulty. This approach is very applicable to in-situ leaching uranium projects, small precious metal operations, etc. The approach to the small project is that of fast-tracking the project in order to minimize the time over which capital expenditure occurs and also to reduce the indirect costs of field expense, construction supplies, construction equipment, etc. In order to fast-track a project it is necessary to do a very precise job on the preliminary phases of the project such as preliminary engineering, plant site location, environmental permits, etc. 2 figures, 2 tables
APPLICATION OF PROJECT MANAGEMENT APPROACHES AT A SMALL BUSINESSES ENTERPRISES
Directory of Open Access Journals (Sweden)
Sergey V. Rajewski
2016-01-01
Full Text Available This article discusses the types of organizational structures of project management and their application in project management in small and medium-sized enterprises. Among the approaches and methods to organize projects emphasizing project management as part of the existing functional structure of the enterprise. Analyzed the most relevant organizational tools of project management in small business: a network schedule; matrix distribution of administrative and management tasks of the project; schedule of the project plan; information and technological methods and models used in the process of project management; software applications for project management, used in the sphere of small business.
Open Source Approach to Project Management Tools
Directory of Open Access Journals (Sweden)
Romeo MARGEA
2011-01-01
Full Text Available Managing large projects involving different groups of people and complex tasks can be challenging. The solution is to use Project management software, which allows a more efficient management of projects. However, famous project management systems can be costly and may require expensive custom servers. Even if free software is not as complex as Microsoft Project, is noteworthy to think that not all projects need all the features, amenities and power of such systems. There are free and open source software alternatives that meet the needs of most projects, and that allow Web access based on different platforms and locations. A starting stage in adopting an OSS in-house is finding and identifying existing open source solution. In this paper we present an overview of Open Source Project Management Software (OSPMS based on articles, reviews, books and developers’ web sites, about those that seem to be the most popular software in this category.
Report of seminar on relativistic approach to nuclear reaction and nuclear structure
International Nuclear Information System (INIS)
1986-05-01
A seminar on 'Relativistic Approach to Nuclear Reaction and Nuclear Structure' was held in 1985 at Osaka University. This booklet includes twenty-four reports given at the seminar, which deal with: Conventional Nonrelativistic Description of Nuclear Matter and Nuclear Spin-Orbit Interactions; Relativistic Approach to Nuclear Structure; Atomic and Molecular Structure Calculations; Electromagnetic Interaction in Nucleus and Relativistic Effect; Nuclear Magnetic Moment in the Relativistic Mean Field Theory, Effective Mass and Particle-Vibration Coupling in the Relativistic σ-ω Model; Gauge Invariance in Relativistic Many-Body Theory; Relativistic Description of Nucleon-Nucleon Interaction in Review; σ-Particle in NN Interaction; Nuclear Optical Potentials Based on the Brueckner-Hartree-Fock Approach; Elastic Backscattering and Optical Potential; Description of Intermediate-Energy Nuclear Reactions; Dirac Phenomenology at E(p) = 65 MeV; Relativistic Impulse Approximation; Reaction Studies with Intermediate Energy Deuterons at SATURNE; Folding Model for Intermediate-Energy Deutron Scattering; Folding Model for Polarized Deutron Scattering at 700 MeV; Dirac Approach Problems and a Different Viewpoint; Relativistic Approach and EMC Effect; Quasielastic Electron Scattering; Response Function of Quasielastic Electron Scattering; Relativistic Hartree Response Function for Quasielastic Electron Scattering on 12 C and 40 Ca; Backflow-, Retardation- and Relativistic Effects on the Longitudinal Response Function of Nuclear Matter; Pion-Photoproduction in the σ-ω Model. (Nogami, K.)
Computational approaches in the design of synthetic receptors - A review.
Cowen, Todd; Karim, Kal; Piletsky, Sergey
2016-09-14
The rational design of molecularly imprinted polymers (MIPs) has been a major contributor to their reputation as "plastic antibodies" - high affinity robust synthetic receptors which can be optimally designed, and produced for a much reduced cost than their biological equivalents. Computational design has become a routine procedure in the production of MIPs, and has led to major advances in functional monomer screening, selection of cross-linker and solvent, optimisation of monomer(s)-template ratio and selectivity analysis. In this review the various computational methods will be discussed with reference to all the published relevant literature since the end of 2013, with each article described by the target molecule, the computational approach applied (whether molecular mechanics/molecular dynamics, semi-empirical quantum mechanics, ab initio quantum mechanics (Hartree-Fock, Møller-Plesset, etc.) or DFT) and the purpose for which they were used. Detailed analysis is given to novel techniques including analysis of polymer binding sites, the use of novel screening programs and simulations of MIP polymerisation reaction. The further advances in molecular modelling and computational design of synthetic receptors in particular will have serious impact on the future of nanotechnology and biotechnology, permitting the further translation of MIPs into the realms of analytics and medical technology. Copyright © 2016 Elsevier B.V. All rights reserved.
RISK MANAGEMENT APPROACHES AND PRACTICES IN IT PROJECTS
Directory of Open Access Journals (Sweden)
BRANDAS Claudiu
2012-07-01
Full Text Available Risk is identified in project management literature as an important factor influencing IT projects success, and it is relevant for both academic and practitionersn#8217; communities. The paper presents the past and current approaches to risk management in IT projects. The objective of this paper is to compare the different approaches and relate them to existing practices. Project management literature and practice have brought different approaches to risk management, and as a result, many projects ended in failure. We present how risk management is considered in the literature, and we compare the main two approaches: the evaluation approach and the management approach. The contingency approach does not consider risk management to be a specific process as it is an embedded process in the other project management processes. Then, we present the main practices in risk management. The methodology applied is based on documentary study review and analysis of the concepts used by the literature. We analyzed the literature published between 1978 and 2011 from the main journals for IT project management and found out that the essence of project management is risk management. The risk management practices have a considerable influence on stakeholdersn#8217; perception of project success. But, regardless of the chosen approach, a standard method for identifying, assessing, and responding to risks should be included in any project as this influences the outcome of the project.
The STAR project: context, objectives and approaches
Furse, M.; Hering, D.; Moog, O.; Verdonschot, P.F.M.; Johnson, R.K.; Brabec, K.; Gritzalis, K.; Buffagni, A.; Pinto, P.; Friberg, N.; Murray-Bligh, J.; Kokes, J.; Alber, R.; Usseglio-Polatera, P.; Haase, P.; Sweeting, R.; Bis, B.; Szoszkiewicz, K.; Soszka, H.; Springe, G.; Sporka, F.; Krno, I.
2006-01-01
STAR is a European Commission Framework V project (EVK1-CT-2001-00089). The project aim is to provide practical advice and solutions with regard to many of the issues associated with the Water Framework Directive. This paper provides a context for the STAR research programme through a review of the
APPLICATION OF PROJECT MANAGEMENT APPROACHES AT A SMALL BUSINESSES ENTERPRISES
Sergey V. Rajewski
2016-01-01
This article discusses the types of organizational structures of project management and their application in project management in small and medium-sized enterprises. Among the approaches and methods to organize projects emphasizing project management as part of the existing functional structure of the enterprise. Analyzed the most relevant organizational tools of project management in small business: a network schedule; matrix distribution of administrative and management tasks of the projec...
Energy Technology Data Exchange (ETDEWEB)
McCurdy, C. William [Univ. of California, Davis, CA (United States). Dept. of
2017-12-14
This project made use of Multiconfiguration Time-Dependent Hartree-Fock method developed earlier in the McCurdy group in a series of novel applications of the method to ultrafast spectroscopic processes. MCTDHF treats the dynamics of a molecule or atom under the influence of an external field in manner that has all electrons active. That property distinguishes this method from the more popular (and much less computationally demanding) approaches for treating the electron dynamics of atoms and molecules in fields, such as the time-dependent “Configuration Interaction Singles” approximation or approaches that limit the treatment to either one or two-electron models.
Stakeholder approach for evaluating organizational change projects.
Peltokorpi, Antti; Alho, Antti; Kujala, Jaakko; Aitamurto, Johanna; Parvinen, Petri
2008-01-01
This paper aims to create a model for evaluating organizational change initiatives from a stakeholder resistance viewpoint. The paper presents a model to evaluate change projects and their expected benefits. Factors affecting the challenge to implement change were defined based on stakeholder theory literature. The authors test the model's practical validity for screening change initiatives to improve operating room productivity. Change initiatives can be evaluated using six factors: the effect of the planned intervention on stakeholders' actions and position; stakeholders' capability to influence the project's implementation; motivation to participate; capability to change; change complexity; and management capability. The presented model's generalizability should be explored by filtering presented factors through a larger number of historical cases operating in different healthcare contexts. The link between stakeholders, the change challenge and the outcomes of change projects needs to be empirically tested. The proposed model can be used to prioritize change projects, manage stakeholder resistance and establish a better organizational and professional competence for managing healthcare organization change projects. New insights into existing stakeholder-related understanding of change project successes are provided.
Systems approach for design control at Monitored Retrievable Storage Project
International Nuclear Information System (INIS)
Kumar, P.N.; Williams, J.R.
1994-01-01
This paper describes the systems approach in establishing design control for the Monitored Retrievable Storage Project design development. Key elements in design control are enumerated and systems engineering aspects are detailed. Application of lessons learned from the Yucca Mountain Project experience is addressed. An integrated approach combining quality assurance and systems engineering requirements is suggested to practice effective design control
A constructivist approach to communication and projection
DEFF Research Database (Denmark)
Skytte, Hans
In connection with a study on relationships between food producers and retail chains a new theory on communication and projection was developed. To position the new theory the paper first gives a short presentation of the traditional communication theory. Then there is a short presentation...... of the paradigm including the research strategy used for the development of the new theory. Following that you will find a section concerning the conceptual framework used for the analysis of the companies. This section is followed by a discussion of the main results and the new communication and projection...
A Communications Approach to Teaching Project Management
DEFF Research Database (Denmark)
Kampf, Constance Elizabeth
2012-01-01
in the Bachelor of Marketing and Management Communication at Aarhus University is examined and analyzed. The presence of the three Design Science Research Cycles combined with both process and product, highlights the critical role of communication in both understanding Project Management and applying Design...... to both frame the learners’ audience for Project Management Writing assignments, and to provide a concrete organizational context to aid in communication practices such as stakeholder analysis, and the development of a critical internal monitor for quality in the learner’s mind. The relevance of Design...
Study on Risk Approaches in Software Development Projects
Directory of Open Access Journals (Sweden)
Claudiu BRANDAS
2012-01-01
Full Text Available Risk approaches in project development led to the integration in the IT project management methodologies and software development of activities and processes of risk management. The diversity and the advanced level of the used technologies in IT projects with increasing com-plexity leads to an exponential diversification of risk factors.The purpose of this research is to identify the level of the risk approach in IT projects both at the IT project management and software development methodologies level and the level of the perception of IT project man-agers, IT managers and IT analysts in Romanian IT companies. Thus, we want to determine the correlation between the use of a project management or software development methodology and the overall level of risk perceived by the project managers using these methodologies.
Learning analytics approach of EMMA project
Tammets, Kairit; Brouns, Francis
2014-01-01
The EMMA project provides a MOOC platform to aggregate and delivers massive open online courses (MOOC) in multiple languages from a variety of European universities. Learning analytics play an important role in MOOCs to support the individual needs of the learner.
Learning from project experiences using a legacy-based approach
Cooper, Lynne P.; Majchrzak, Ann; Faraj, Samer
2005-01-01
As project teams become used more widely, the question of how to capitalize on the knowledge learned in project teams remains an open issue. Using previous research on shared cognition in groups, an approach to promoting post-project learning was developed. This Legacy Review concept was tested on four in tact project teams. The results from those test sessions were used to develop a model of team learning via group cognitive processes. The model and supporting propositions are presented.
Project management a systems approach to planning, scheduling, and controlling
Kerzner, Harold
2013-01-01
The bestselling project management text for students andprofessionals-now updated and expanded This Eleventh Edition of the bestselling "bible" ofproject management maintains the streamlined approach of the prioreditions and moves the content even closer to PMI's ProjectManagement Body of Knowledge (PMBOK). New content has been added tothis edition on measuring project management ROI, value to theorganization and to customers, and much more. The capstone "super"case on the "Iridium Project" has been maintained, covering allaspects of project management. Increased use of sidebars throughoutthe book helps further align it with the PMBOK and the ProjectManagement Professional (PMP) Certification Exam. This new edition features significant expansion, including morethan three dozen entirely new sections and updates on processsupporting; types of project closure; project sponsorship; andculture, teamwork, and trust. This comprehensive guide to theprinciples and practices of project management: Offers new sections...
A new approach to the semi-classical relativistic two-body problem for charged fermions
International Nuclear Information System (INIS)
Leiter, D.
1978-01-01
Generalizing from a recently developed hybrid formulation of classical electrodynamics with ''direct (charge-field) action'' structure an analogous semi-classical Dirac formulation of the theory is constructed, which is capable of describing the semi-classical quantum mechanics of two identical spin-1/2 particles. This semi-classical formulation is to be used as a heuristic aid in searching for the theoretical structure of a fully ''second quantized'' theory. The Pauli exclusion principle is incorporated by making the interaction fields (in the action principle) antisymmetric with respect to ''charge-field'' labeling. In this manner, ''position correlation'' effects associated with ''configuration interaction'' can also be accounted for. By studying the nature of the stationary-state solutions, the formalism is compared with the conventional quantum-mechanical one (to understand the similarities and the differences between this approach and the usual correlated Hartree-Fock approximation of ordinary relativistic quantum theory). The stationary-state solutions to the semi-classical formalism are shown to closely approximate the usual quantum-mechanical solutions when the wave functions are represented as a superposition of Slater determinants of Dirac-Coulombic-type wave functions with radial parts having a form which extremizes the total Breit energy. The manner in which this semi-classical theory might be extended to a fully ''second quantized'' formalism is sketched. (author)
A density variational approach to nuclear giant resonances at zero and finite temperature
International Nuclear Information System (INIS)
Gleissl, P.; Brack, M.; Quentin, P.; Meyer, J.
1989-02-01
We present a density functional approach to the description of nuclear giant resonances (GR), using Skyrme type effective interactions. We exploit hereby the theorems of Thouless and others, relating RPA sum rules to static (constrained) Hartree-Fock expectation values. The latter are calculated both microscopically and, where shell effects are small enough to allow it, semiclassically by a density variational method employing the gradient-expanded density functionals of the extended Thomas-Fermi model. We obtain an excellent overall description of both systematics and detailed isotopic dependence of GR energies, in particular with the Skyrme force SkM. For the breathing modes (isoscalar and isovector giant monopole modes), and to some extent also for the isovector dipole mode, the A-dependence of the experimental peak energies is better described by coupling two different modes (corresponding to two different excitation operators) of the same spin and parity and evaluating the eigenmodes of the coupled system. Our calculations are also extended to highly excited nuclei (without angular momentum) and the temperature dependence of the various GR energies is discussed
Li, Chenyang; Verma, Prakash; Hannon, Kevin P.; Evangelista, Francesco A.
2017-08-01
We propose an economical state-specific approach to evaluate electronic excitation energies based on the driven similarity renormalization group truncated to second order (DSRG-PT2). Starting from a closed-shell Hartree-Fock wave function, a model space is constructed that includes all single or single and double excitations within a given set of active orbitals. The resulting VCIS-DSRG-PT2 and VCISD-DSRG-PT2 methods are introduced and benchmarked on a set of 28 organic molecules [M. Schreiber et al., J. Chem. Phys. 128, 134110 (2008)]. Taking CC3 results as reference values, mean absolute deviations of 0.32 and 0.22 eV are observed for VCIS-DSRG-PT2 and VCISD-DSRG-PT2 excitation energies, respectively. Overall, VCIS-DSRG-PT2 yields results with accuracy comparable to those from time-dependent density functional theory using the B3LYP functional, while VCISD-DSRG-PT2 gives excitation energies comparable to those from equation-of-motion coupled cluster with singles and doubles.
Nonsequential multiphoton double ionization of He in intense laser - a QED approach
International Nuclear Information System (INIS)
Bhattacharyya, S.; Mazumder, Mina; Chakrabarti, J.; Faisal, F.H.M.
2010-01-01
The non-sequential muItiphoton double ionization (NSDI) of He in intense laser field is not yet completely understood, more so for spin resolved currents. We are tempted to use QED and Feynman diagram to obtain spin polarized currents. Hartree-Fock (HF) ground-state correlated wave function of He atom is considered in circularly polarized laser. In QED approach one of the electrons is directly ionized by photon absorption while the second electron is shaken off due to the change in the internal potential of the atom. In He-atom the two ionized electrons can only be in the singlet spin state. Spin-symmetric and spin-flip transitions are eventually possible for the direct and the shake-off electrons. In an ensemble of (HF type) He-atoms the ionized Volkov electrons may acquire 4 pairs of momenta indicating e-e correlation in the final state. Coulomb correction is taken care off through the Sommerfeld factor
Mizell, Carolyn; Malone, Linda
2007-01-01
It is very difficult for project managers to develop accurate cost and schedule estimates for large, complex software development projects. None of the approaches or tools available today can estimate the true cost of software with any high degree of accuracy early in a project. This paper provides an approach that utilizes a software development process simulation model that considers and conveys the level of uncertainty that exists when developing an initial estimate. A NASA project will be analyzed using simulation and data from the Software Engineering Laboratory to show the benefits of such an approach.
Project management a systems approach to planning, scheduling, and controlling
Kerzner, Harold
2017-01-01
Project Management is the bestselling text for students and professionals, presenting a streamlined approach to project management functions in full alignment with PMI(r)'s latest Project Management Body of Knowledge (PMBOK(r)). This new 12th edition has been updated to reflect the latest changes found in the PMBOK(r) Guide--Sixth Edition, and features new coverage of emerging topics including global stakeholder management, causes of failure, agile project management, project governance failure, customer approval milestones, classifying project metrics, and more. Supplementary materials are available for students, working professionals, and instructors. * Understand organizational structures and project management functions * Learn how to control costs, manage risk, and analyze trade-offs * Examine different methods used for planning, scheduling, QA, and more * Work effectively with customers and stakeholders from around the globe Project Management is the comprehensive reference to keep within arm's reach. ...
Integration of case study approach, project design and computer ...
African Journals Online (AJOL)
Integration of case study approach, project design and computer modeling in managerial accounting education ... Journal of Fundamental and Applied Sciences ... in the Laboratory of Management Accounting and Controlling Systems at the ...
Incentive Structure of Financing a Project: An Islamic Finance Approach
Lone, Fayaz Ahmad; Quadir, Abdul
2017-01-01
Financing is an important component in any project. Without finance, it is impossible to run any project as it is considered the lifeblood of the business. But due to the presence of predetermined rate of interest, economists have provided alternative approach for financing the project. In this paper a model using Profit and Loss Sharing (PLS) system and comparison of it with the conventional financing model is developed. Thrust in this paper is towards establishing a new theoretical reasonin...
Regional Integrated Silvopastoral Approaches to Ecosystem Management Project
CIPAV (Centre For Research on Sustainable Agricultural Production Systems); CATIE (Centro Agronomico Tropical de Investigacion y Ensenanza); NITLAPAN
2007-01-01
Metadata only record The Regional Integrated Silvopastoral Approaches to Ecosystem Management Project introduces the payment for environmental services approach to silvopastoral farmers in Colombia, Costa Rica, and Nicaragua. The objectives of the project are to "demonstrate and measure a) the effects the introduction of payment incentives for environmental services to farmers on their adoption of integrated silvopastoral farming systems in degraded pasture lands; and b) the resulting impr...
Approaches to Teaching Plant Nutrition. Children's Learning in Science Project.
Leeds Univ. (England). Centre for Studies in Science and Mathematics Education.
During the period 1984-1986, over 30 teachers from the Yorkshire (England) region have worked in collaboration with the Children's Learning in Science Project (CLIS) developing and testing teaching schemes in the areas of energy, particle theory, and plant nutrition. The project is based upon the constructivist approach to teaching. This document…
A Project-based Learning approach for teaching Robotics to ...
African Journals Online (AJOL)
In this research we used a project-based learning approach to teach robotics basics to undergraduate business computing students. The course coverage includes basic electronics, robot construction and programming using arduino. Students developed and tested a robot prototype. The project was evaluated using a ...
Energy Technology Data Exchange (ETDEWEB)
Simenel, C.; Avez, B. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules de Physique Nucleaire et de l' Instrumentation Associee (DSM/DAPNIA/SPhN), 91- Gif sur Yvette (France); Lacroix, D. [GANIL, 14 - Caen (France)
2007-07-01
This lecture introduces several microscopic approaches to nuclear dynamics. Our goal is to provide a good description of low energy heavy ions collisions. We study both the formalism and the practical application of the time-dependent Hartree-Fock (TDHF) theory. The TDHF approach gives a mean field dynamics of the system under the assumption of independent particles. As an example, we study the fusion of both spherical and deformed nuclei with TDHF. We also show that nucleon transfer may occur between nuclei below the barrier. These studies allow us to specify the field of applications of TDHF in one hand, and, in the other hand, its intrinsic limitations, as for instance the fact that there is no fusion by tunnel effect with TDHF. It is then important to get rid of the independent particle assumption. We finally present some approaches to go beyond TDHF, including for instance pairing and/or collision term between nucleons, though only few realistic applications have been performed so far. (authors)
Project approach study for nuclear power plants in the Netherlands
International Nuclear Information System (INIS)
1985-11-01
The new nuclear program in the Netherlands comprises the construction of two to four nuclear power plants up to the year 2000. The main objective pursued with the implementation of the nuclear program is the supply of low-cost electricity in the future. In order to prepare the program and to provide a basis for further decisions, the Ministry of Economic Affairs has entrusted Motor-Columbus Consulting Engineers Inc., Baden, Switzerland, with a study to determine the most suitable project approach option(s) for the implementation of the future nuclear program in the Netherlands. In carrying out this study, Motor-Columbus investigated the following main project approach options: 1. turnkey contract approach; 2. split-package contract approach; 3. multi-contract approach. It is concluded that if applied in the appropriate way, the normal turnkey contract approach represents the most suitable approach under the prevailing situation in the Netherlands. (orig.)
Towards e-Government project assessment: European approach
Directory of Open Access Journals (Sweden)
Pavel Mates
2013-06-01
Full Text Available The objective of the paper is to analyse current approaches to the assessment of e-Government projects as the specifi c public projects and to suggest how to improve these approaches in order to eliminate their shortcomings. The nonnormative theoretical methods are used to analyse empirical results of previous researches; particularly the deduction method is used to prove that current approaches to the evaluation of e-Government projects have some inequalities, the analogy and comparison methods are used to create general typology of e-Government projects and the induction method is used to seek examples of the indicators and metrics. The results are based on analysis of extensive amount of e-Government projects, which have been realized in different European countries in the past twenty years. The basic result of the research is creation of the ten most common types of e-Government projects typology. The fundamental conclusion obtained from the results of this research is that this typology can be used as the core of new E-Government General Assessment Framework, which eliminates problems of previous approaches, allows adjusting metrics and indicators to each type of projects, keeps comparability of results and thus making possible the use of benchmarking methods.
System supplier approach to projects and operations efficiency
Energy Technology Data Exchange (ETDEWEB)
Moe, P O [Siemens Offshore A/S (Norway)
1994-12-31
The conference paper outlines the most important elements for a new approach to project realisation that enable a cost reduction of 30-50% compared to conventional methods. The achievements are based on studies and evaluations to the Norwegian Vigdis development project. The system elements covered are the electrical and automation systems including safety and process control and all traditional phases of a project from concept design to the operational phase. The concept involves new principles for project execution where traditional borderlines and interfaces between the various participants have been redefined. Management attention has been verified as an important prerequisite for a successful implementation of this strategy. 2 figs.
A new approach to cost effective projects: High performance project teams
International Nuclear Information System (INIS)
Chambers, N.C.
1994-01-01
In low oil price environment in which environmental conditions are more challenging, reservoir characteristics less favourable and political risk increasing, successful projects are required in such cases. The present paper deals with the visionary process of establishing high performance project teams. According to the author, such project teams embody dynamic recognition of holism. Holism is achieved as an output from the process of establishing the drivers and enablers for success on a project. They are given birth during the unfolding of the operators development plans and contracting strategy. The paper discusses the main drivers of project teams comprising purpose and performance goals, selection, common approach, commitment and accountability, and financial alignment
A new approach to cost effective projects: High performance project teams
Energy Technology Data Exchange (ETDEWEB)
Chambers, N.C. [Brown and Root Energy Services (United Kingdom)
1994-12-31
In low oil price environment in which environmental conditions are more challenging, reservoir characteristics less favourable and political risk increasing, successful projects are required in such cases. The present paper deals with the visionary process of establishing high performance project teams. According to the author, such project teams embody dynamic recognition of holism. Holism is achieved as an output from the process of establishing the drivers and enablers for success on a project. They are given birth during the unfolding of the operators development plans and contracting strategy. The paper discusses the main drivers of project teams comprising purpose and performance goals, selection, common approach, commitment and accountability, and financial alignment
Budgetary Approach to Project Management by Percentage of Completion Method
Directory of Open Access Journals (Sweden)
Leszek Borowiec
2011-07-01
Full Text Available Efficient and effective project management process is made possible by the use of methods and techniques of project management. The aim of this paper is to present the problems of project management by using Percentage of Completion method. The research material was gathered based on the experience in implementing this method by the Johnson Controls International Company. The article attempts to demonstrate the validity of the thesis that the POC project management method, allows for effective implementation and monitoring of the project and thus is an effective tool in the managing of companies which exploit the budgetary approach. The study presents planning process of basic parameters affecting the effectiveness of the project (such as costs, revenue, margin and characterized how the primary measurements used to evaluate it. The present theme is illustrating by numerous examples for showing the essence of the raised problems and the results are presenting by using descriptive methods, graphical and tabular.
Lattice Dynamics of Beryllium from a First-Principles Nonlocal Pseudopotential Approach
DEFF Research Database (Denmark)
Walter, F. King; Cutler, P. H.
1970-01-01
dielectric-screening function employing the Kohn-Sham approximation for exchange among the conduction electrons. The energy-wave-number characteristic F(q) is constructed from the Hartree-Fock-Slater (HFS) wave function for Be++; this is used to calculate the phonon dispersion relations in the [0001], [011̅...
Reference Scenario Forecasting: A New Approach to Transport Project Assessment
DEFF Research Database (Denmark)
Salling, Kim Bang; Leleur, Steen; Skougaard, Britt Zoëga
2010-01-01
This paper presents a new approach to transport project assessment in terms of feasibility risk assessment and reference class forecasting. Normally, transport project assessment is based upon a cost-benefit approach where evaluation criteria such as net present values are obtained. Recent research...... construction cost estimates. Hereafter, a quantitative risk analysis is provided making use of Monte Carlo simulation. This stochastic approach facilitates random input parameters based upon reference class forecasting, hence, a parameter data fit has been performed in order to obtain validated probability...... forecasting (RSF) frame. The RSF is anchored in the cost-benefit analysis (CBA), thus, it provides decision-makers with a quantitative mean of assessing the transport infrastructure project. First, the RSF method introduces uncertainties within the CBA by applying Optimism Bias uplifts on the preliminary...
Application of the graded management approach to Battelle's nuclear project
International Nuclear Information System (INIS)
Voth, C.B.
1996-01-01
Battelle's graded management approach provides an effective and efficient method to perform the Battelle Columbus Laboratories Decommissioning Project (BCLDP). The project is managed by Battelle under their US Nuclear Regulatory Commission (NRC) license but is partially funded by the US Department of Energy (DOE) on a cost-shared basis. Battelle's graded management approach adheres to the regulations and orders governing the BCLDP by the interaction of various plans, procedures, permits, and work instructions. By independent assessment, quality control, and worker training, Battelle has been able to establish a cost-effective approach to performing work and, at the same time, have a controlled checks and balance system to assure the proper safety considerations and project particulars are taken into account
Multiobjective genetic algorithm approaches to project scheduling under risk
Kılıç, Murat; Kilic, Murat
2003-01-01
In this thesis, project scheduling under risk is chosen as the topic of research. Project scheduling under risk is defined as a biobjective decision problem and is formulated as a 0-1 integer mathematical programming model. In this biobjective formulation, one of the objectives is taken as the expected makespan minimization and the other is taken as the expected cost minimization. As the solution approach to this biobjective formulation genetic algorithm (GA) is chosen. After carefully invest...
International Nuclear Information System (INIS)
Fox, D.J.
1983-10-01
Analytic derivatives of the potential energy for Self-Consistent-Field (SCF) wave functions have been developed in recent years and found to be useful tools. The first derivative for configuration interaction (CI) wave functions is also available. This work details the extension of analytic methods to energy second derivatives for CI wave functions. The principal extension required for second derivatives is evaluation of the first order change in the CI wave function with respect to a nuclear perturbation. The shape driven graphical unitary group approach (SDGUGA) direct CI program was adapted to evaluate this term via the coupled-perturbed CI equations. Several iterative schemes are compared for use in solving these equations. The pilot program makes no use of molecular symmetry but the timing results show that utilization of molecular symmetry is desirable. The principles for defining and solving a set of symmetry adapted equations are discussed. Evaluation of the second derivative also requires the solution of the second order coupled-perturbed Hartree-Fock equations to obtain the correction to the molecular orbitals due to the nuclear perturbation. This process takes a consistently higher percentage of the computation time than for the first order equations alone and a strategy for its reduction is discussed
Abramov, Y A; Volkov, A; Wu, G; Coppens, P
2000-11-01
A new module interfaced to the XD programming package has been used in the evaluation of intermolecular interactions and lattice energies of the crystals of p-nitroaniline, L-asparagine monohydrate and the pentapeptide Boc-Gln-D-Iva-Hyp-Ala-Phol (Boc = butoxycarbonyl, Iva = isovaline = ethylalanine, Phol = phenylalaninol). The electrostatic interactions are evaluated with the atom-centered distributed multipoles from KRMM (kappa'-restricted multipole model) refinements, using the Buckingham expression for non-overlapping charge densities. Results for p-nitroaniline are compared with Hartree-Fock (HF), density functional (DFT) and Moller-Plesset (MP2) supermolecular calculations and with HF and DFT periodic calculations. The HF and DFT methods fail to predict the stability of the p-nitroaniline crystal but the results of the experimental charge-density approach (ECDA) are in good agreement with both MP2 interaction energies and the experimental lattice energy. ECDA results for L-asparagine monohydrate compare well with those from DFT supermolecular and periodic HF calculations. The disorder of the terminal group in the pentapeptide, which persists at the experimental temperature of 20 K, corresponds to an energy difference of only 0.35 kJ mol(-1), which is too small to be reproduced with current methods.
Chatterjee, D.; Gulminelli, F.; Raduta, Ad. R.; Margueron, J.
2017-12-01
The question of correlations among empirical equation of state (EoS) parameters constrained by nuclear observables is addressed in a Thomas-Fermi meta-modeling approach. A recently proposed meta-modeling for the nuclear EoS in nuclear matter is augmented with a single finite size term to produce a minimal unified EoS functional able to describe the smooth part of the nuclear ground state properties. This meta-model can reproduce the predictions of a large variety of models, and interpolate continuously between them. An analytical approximation to the full Thomas-Fermi integrals is further proposed giving a fully analytical meta-model for nuclear masses. The parameter space is sampled and filtered through the constraint of nuclear mass reproduction with Bayesian statistical tools. We show that this simple analytical meta-modeling has a predictive power on masses, radii, and skins comparable to full Hartree-Fock or extended Thomas-Fermi calculations with realistic energy functionals. The covariance analysis on the posterior distribution shows that no physical correlation is present between the different EoS parameters. Concerning nuclear observables, a strong correlation between the slope of the symmetry energy and the neutron skin is observed, in agreement with previous studies.
A Systematic Approach to Modelling Change Processes in Construction Projects
Directory of Open Access Journals (Sweden)
Ibrahim Motawa
2012-11-01
Full Text Available Modelling change processes within construction projects isessential to implement changes efficiently. Incomplete informationon the project variables at the early stages of projects leads toinadequate knowledge of future states and imprecision arisingfrom ambiguity in project parameters. This lack of knowledge isconsidered among the main source of changes in construction.Change identification and evaluation, in addition to predictingits impacts on project parameters, can help in minimising thedisruptive effects of changes. This paper presents a systematicapproach to modelling change process within construction projectsthat helps improve change identification and evaluation. Theapproach represents the key decisions required to implementchanges. The requirements of an effective change processare presented first. The variables defined for efficient changeassessment and diagnosis are then presented. Assessmentof construction changes requires an analysis for the projectcharacteristics that lead to change and also analysis of therelationship between the change causes and effects. The paperconcludes that, at the early stages of a project, projects with a highlikelihood of change occurrence should have a control mechanismover the project characteristics that have high influence on theproject. It also concludes, for the relationship between changecauses and effects, the multiple causes of change should bemodelled in a way to enable evaluating the change effects moreaccurately. The proposed approach is the framework for tacklingsuch conclusions and can be used for evaluating change casesdepending on the available information at the early stages ofconstruction projects.
A projective approach to a language of landscape design
Directory of Open Access Journals (Sweden)
Catherine Ward Thompson
1997-10-01
Full Text Available Building on the work of Kelly (1955 in personal construct psychology, and Peled (1976, I990 in ecoanalysis, this paper develops projective techniques-which use concepts of personal and phenomenological space-as a means for articulating approaches to landscape design. The projective approach involves two stages. In stage one, projective techniques are used to elicit personal constructs (which may be held at a pre-conscious or sub-conscious level, allowing the holistic experience of landscape to be explored. In stage two, using a 'projection location task' derived from the way we experience and construe the regions of our own bodies, elements of these constructs can then be articulated so as to inform the way we interact and engage with the space around us. This gives insight into the meaning of spatial layouts, which can then be translated into a design language for the structural ordering of space. The author draws on original research conducted with children as well as adults, using projective techniques to draw out their desires and needs in relation to designing their landscape environment. The paper discusses the value of such methods for landscape designers and their clients, and outlines some ongoing research to test the validity of the projection location task.
A Differential Geometric Approach to Nonlinear Filtering: The Projection Filter
Brigo, D.; Hanzon, B.; LeGland, F.
1998-01-01
This paper presents a new and systematic method of approximating exact nonlinear filters with finite dimensional filters, using the differential geometric approach to statistics. The projection filter is defined rigorously in the case of exponential families. A convenient exponential family is
Implementing Project Based Learning Approach to Graphic Design Course
Riyanti, Menul Teguh; Erwin, Tuti Nuriah; Suriani, S. H.
2017-01-01
The purpose of this study was to develop a learning model based Commercial Graphic Design Drafting project-based learning approach, was chosen as a strategy in the learning product development research. University students as the target audience of this model are the students of the fifth semester Visual Communications Design Studies Program…
Diversity Management Change Projects: In Need of Alternative Conceptual Approaches?
Directory of Open Access Journals (Sweden)
Christina Evans
2012-09-01
Full Text Available Drawing on a meta-analysis of an evaluation of a European Social Fund project aimed at enhancing employment opportunities for women in Information Technology, Electronic and Computing (ITEC, this paper critically debates how effectual a diversity management approach alone is as an underpinning rationale for change in the complex area of diversity. The paper draws on the experiences of ‘partner organizations’, gathered through interviews conducted during the evaluation stage of the project. The paper discusses some of the tensions experienced by partner organizations, thus providing new insights into why such projects are not as effectual as they might be. The paper concludes by presenting a case for the need to re-conceptualise how change as part of a wider diversity management approach might best be conceptualized. We suggest that a ‘systems approach’ could prove a more fruitful way of conceptualizing change of this nature given the inter-dependences between different organizations and institutions.
Incremental projection approach of regularization for inverse problems
Energy Technology Data Exchange (ETDEWEB)
Souopgui, Innocent, E-mail: innocent.souopgui@usm.edu [The University of Southern Mississippi, Department of Marine Science (United States); Ngodock, Hans E., E-mail: hans.ngodock@nrlssc.navy.mil [Naval Research Laboratory (United States); Vidard, Arthur, E-mail: arthur.vidard@imag.fr; Le Dimet, François-Xavier, E-mail: ledimet@imag.fr [Laboratoire Jean Kuntzmann (France)
2016-10-15
This paper presents an alternative approach to the regularized least squares solution of ill-posed inverse problems. Instead of solving a minimization problem with an objective function composed of a data term and a regularization term, the regularization information is used to define a projection onto a convex subspace of regularized candidate solutions. The objective function is modified to include the projection of each iterate in the place of the regularization. Numerical experiments based on the problem of motion estimation for geophysical fluid images, show the improvement of the proposed method compared with regularization methods. For the presented test case, the incremental projection method uses 7 times less computation time than the regularization method, to reach the same error target. Moreover, at convergence, the incremental projection is two order of magnitude more accurate than the regularization method.
Al-Azmi, Amal; Shalaby, Mona Abbas
2018-03-01
A green, fast and straightforward procedure for the synthesis of (E)-3-(3-(4-nitrophenyl)triaz-1-en-1-yl)-1H-pyrazole-4-carbonitrile is described in this paper. The method uses a coupling reaction between 4- nitrophenyl diazonium chloride and 5-aminopyrazole-4-carbonitrile. The structure is confirmed by different spectroscopic studies such as IR, NMR, HRMS and UV-vis spectroscopy in addition to X-ray single-crystal determination. The molecular geometry, vibrational frequencies and gauge-invariant atomic orbital (GIAO) 1H and 13C NMR chemical shift values of (E)-3-(3-(4-nitrophenyl)triaz-1-en-1-yl)-1H-pyrazole-4-carbonitrile are calculated in the ground state using the Hartree-Fock (HF) method and density functional theory (DFT) with the 6-31G(d) basis set, and are compared with the experimental data. The natural bond orbital (NBO) analysis is performed so as to discuss the stability of the molecule that arises from hyper conjugative interactions and charge delocalization. The electronic properties, such as HOMO and LUMO energies, were calculated using time dependent density functional theory (TD-DFT) approach.
Problems and Projects Based Approach For Analog Electronic Circuits' Course
Directory of Open Access Journals (Sweden)
Vahé Nerguizian
2009-04-01
Full Text Available New educational methods and approaches are recently introduced and implemented at several North American and European universities using Problems and Projects Based Approach (PPBA. The PPBA employs a teaching technique based mostly on competences/skills rather than only on knowledge. This method has been implemented and proven by several pedagogical instructors and authors at several educational institutions. This approach is used at different disciplines such as medicine, biology, engineering and many others. It has the advantage to improve the student's skills and the knowledge retention rate, and reflects the 21st century industrial/company needs and demands. Before implementing this approach to a course, a good resources preparation and planning is needed upfront by the responsible or instructor of the course to achieve the course and students related objectives. This paper presents the preparation, the generated documentation and the implementation of a pilot project utilizing PPBA education for a second year undergraduate electronic course over a complete semester, and for two different class groups (morning and evening groups. The outcome of this project (achieved goals, observed difficulties and lessons learned is presented based on different tools such as students 'in class' communication and feedback, different course evaluation forms and the professor/instructor feedback. Resources, challenges, difficulties and recommendations are also assessed and presented. The impact, the effect and the results (during and at the end of the academic fall session of the PPBA on students and instructor are discussed, validated, managed and communicated to help other instructor in taking appropriate approach decisions with respect to this new educational approach compared to the classical one.
National conversion pilot project: A creative approach to recyling
International Nuclear Information System (INIS)
Gandee, K.R.; Taylor, R.A.; Cornils, K.N.
1995-01-01
As a result of the Bush-Yeltsin summit in 1991, the U.S. Department of Energy (DOE) has undergone a significant downsizing of its defense mission. In July 1992, the Rocky Flats site in Colorado was the first DOE site to be closed. Its mission was changed from defense to environmental cleanup and economic development. Recognizing the need to assist displaced workers and affected communities and to conduct cost-effective cleanup of DOE sites, Congress initiated two legislative provisions in the 1994 National Defense Authorization Act that required DOE to (a) provide local impact assistance to communities that are affected by the defense downsizing and (b) conduct at least One waste recycling project within the 1994 fiscal year. At the Rocky Flats site, the National Conversion Pilot Project represents an innovative approach in which both Congressional requirements are achieved simultaneously, and the strategy for meeting these requirements was developed through the active participation of all stakeholders of the project
Large scale nuclear structure studies
International Nuclear Information System (INIS)
Faessler, A.
1985-01-01
Results of large scale nuclear structure studies are reported. The starting point is the Hartree-Fock-Bogoliubov solution with angular momentum and proton and neutron number projection after variation. This model for number and spin projected two-quasiparticle excitations with realistic forces yields in sd-shell nuclei similar good results as the 'exact' shell-model calculations. Here the authors present results for a pf-shell nucleus 46 Ti and results for the A=130 mass region where they studied 58 different nuclei with the same single-particle energies and the same effective force derived from a meson exchange potential. They carried out a Hartree-Fock-Bogoliubov variation after mean field projection in realistic model spaces. In this way, they determine for each yrast state the optimal mean Hartree-Fock-Bogoliubov field. They apply this method to 130 Ce and 128 Ba using the same effective nucleon-nucleon interaction. (Auth.)
Six Sigma Project Selection Using Fuzzy TOPSIS Decision Making Approach
Directory of Open Access Journals (Sweden)
Rajeev Rathi
2015-05-01
Full Text Available Six Sigma is considered as a logical business strategy that attempts to identify and eliminate the defects or failures for improving the quality of product and processes. A decision on project selection in Six Sigma is always very critical; it plays a key role in successful implementation of Six Sigma. Selection of a right Six Sigma project is essentially important for an automotive company because it greatly influences the manufacturing costs. This paper discusses an approach for right Six Sigma project selection at an automotive industry using fuzzy logic based TOPSIS method. The fuzzy TOPSIS is a well recognized tool to undertake the fuzziness of the data involved in choosing the right preferences. In this context, evaluation criteria have been designed for selection of best alternative. The weights of evaluation criteria are calculated by using the MDL (modified digital logic method and final ranking is calculated through priority index obtained by using fuzzy TOPSIS method. In the selected case study, this approach has rightly helped to identify the right project for implementing Six Sigma for achieving improvement in productivity.
Directory of Open Access Journals (Sweden)
Maurizio Bevilacqua
2014-09-01
Full Text Available Purpose: This work investigates the influence of project managers’ personality on the success of a project in a Multinational Corporation. The methodology proposed for analyzing the project managers’ personality is based on the Myers-Briggs Type Indicator.Design/methodology/approach: Forty projects carried out in 2012 by multinational corporation, concerning new product development (NPD, have been analyzed, comparing the profile of project managers with results obtained in terms of traditional performance indexes (time delay and over-budget of projects and performance indexes usually used in “Lean Production” sector (waste time and type of “wastes”. A detailed analysis of the most important “wastes” during the project development is carried out using the Value Stream Mapping (VSM technique.Findings and Originality/value: Relying on the Myers–Briggs personality instrument, results show that extroverted managers (as opposed to introverted managers carry out projects that show lower delay and lower waste time. Introverted managers often make “Over-processing” and “Defect” types of waste. Moreover, lower delay and over-budget have been shown by perceiving managers.Research limitations: Regarding the limitations of this work it is necessary to highlight that we collected data from project managers in a retrospective way. While we believe that several aspects of our data collection effort helped enhance the accuracy of the results, future research could conduct real-time case study research to get more detailed insights into the proposed relationships and avoid retrospective bias. Moreover we focused on a single respondent, the project manager. This helped us ensure that their interpretations played an important role in product development. But, we cannot examined the opinion of team members that could be different from project managers opinion regarding some questions.Originality/value: This research provides insight useful
A simplified approach for the coupling of excitation energy transfer
Energy Technology Data Exchange (ETDEWEB)
Shi Bo [Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026 (China); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China); Gao Fang, E-mail: gaofang@iim.ac.cn [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031 (China); State Key Laboratory of Robotics, Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang 110016 (China); Liang Wanzhen [Hefei National Laboratory for Physical Science at Microscale, University of Science and Technology of China, Hefei 230026 (China); Department of Chemical Physics, University of Science and Technology of China, Hefei 230026 (China)
2012-02-06
Highlights: Black-Right-Pointing-Pointer We propose a simple method to calculate the coupling of singlet-to-singlet and triplet-to-triplet energy transfer. Black-Right-Pointing-Pointer Coulomb term are the major contribution to the coupling of singlet-to-singlet energy transfer. Black-Right-Pointing-Pointer Effect from the intermolecular charge-transfer states dorminates in triplet-to-triplet energy transfer. Black-Right-Pointing-Pointer This method can be expanded by including correlated wavefunctions. - Abstract: A simplified approach for computing the electronic coupling of nonradiative excitation-energy transfer is proposed by following Scholes et al.'s construction on the initial and final states [G.D. Scholes, R.D. Harcourt, K.P. Ghiggino, J. Chem. Phys. 102 (1995) 9574]. The simplification is realized through defining a set of orthogonalized localized MOs, which include the polarization effect of the charge densities. The method allows calculating the coupling of both the singlet-to-singlet and triplet-to-triplet energy transfer. Numerical tests are performed for a few of dimers with different intermolecular orientations, and the results demonstrate that Coulomb term are the major contribution to the coupling of singlet-to-singlet energy transfer whereas in the case of triplet-to-triplet energy transfer, the dominant effect is arisen from the intermolecular charge-transfer states. The present application is on the Hartree-Fock level. However, the correlated wavefunctions which are normally expanded in terms of the determinant wavefunctions can be employed in the similar way.
DEFF Research Database (Denmark)
Norman, Patrick; Schimmelpfennig, Bernd; Ruud, Kenneth
2002-01-01
A systematic investigation of a hierarchy of methods for including relativistic effects in the calculation of linear and nonlinear optical properties was carried out. The simple ECP method and the more involved spin-averaged Douglas-Kroll approximation were compared to benchmark results obtained...
Van Meer, R.; Gritsenko, O. V.; Baerends, E. J.
2017-01-01
Straightforward interpretation of excitations is possible if they can be described as simple single orbital-to-orbital (or double, etc.) transitions. In linear response time-dependent density functional theory (LR-TDDFT), the (ground state) Kohn-Sham orbitals prove to be such an orbital basis. In
International Nuclear Information System (INIS)
Amaral, N.C.; Maffeo, B.; Guenzburger, D.J.R.
1982-01-01
Molecular orbitals calculations were performed for clusters representing the CaF 2 , SrF 2 and BaF 2 ionic crystals. The discrete variational method was employed, with the Xα approximation for the exchange interaction; a detailed investigation of different models for embedding the clusters in the solids led to a realistic description of the effect of neighbour ions in the infinite crystal. The results obtained were used to interpret optical and photoelectron data reported in the literature. In the case of CaF 2 , comparisons were made with existing band structure calculations. (Author) [pt
A novel approach to transformed biometrics using successive projections
Gopi, E. S.
2010-02-01
Unlike user created password, number of biometrics is limited for creating account in different organizations. Transformed biometrics attempts to solve the problem by transforming the biometric into another form, which is unique to the particular organization. This makes the availability of different transformed biometrics in different organizations transformed from the same biometrics and helps in foolproof transactions. In this article a novel approach to transformed biometrics using successive projection technique is suggested .In the proposed technique, the user can register up to 5*4n-1 organizations if the length of the biometric password is 'n'.
Modeling of problems of projection: A non-countercyclic approach
Directory of Open Access Journals (Sweden)
Jason Ginsburg
2016-06-01
Full Text Available This paper describes a computational implementation of the recent Problems of Projection (POP approach to the study of language (Chomsky 2013; 2015. While adopting the basic proposals of POP, notably with respect to how labeling occurs, we a attempt to formalize the basic proposals of POP, and b develop new proposals that overcome some problems with POP that arise with respect to cyclicity, labeling, and wh-movement operations. We show how this approach accounts for simple declarative sentences, ECM constructions, and constructions that involve long-distance movement of a wh-phrase (including the that-trace effect. We implemented these proposals with a computer model that automatically constructs step-by-step derivations of target sentences, thus making it possible to verify that these proposals work.
Integrated variable projection approach (IVAPA) for parallel magnetic resonance imaging.
Zhang, Qiao; Sheng, Jinhua
2012-10-01
Parallel magnetic resonance imaging (pMRI) is a fast method which requires algorithms for the reconstructing image from a small number of measured k-space lines. The accurate estimation of the coil sensitivity functions is still a challenging problem in parallel imaging. The joint estimation of the coil sensitivity functions and the desired image has recently been proposed to improve the situation by iteratively optimizing both the coil sensitivity functions and the image reconstruction. It regards both the coil sensitivities and the desired images as unknowns to be solved for jointly. In this paper, we propose an integrated variable projection approach (IVAPA) for pMRI, which integrates two individual processing steps (coil sensitivity estimation and image reconstruction) into a single processing step to improve the accuracy of the coil sensitivity estimation using the variable projection approach. The method is demonstrated to be able to give an optimal solution with considerably reduced artifacts for high reduction factors and a low number of auto-calibration signal (ACS) lines, and our implementation has a fast convergence rate. The performance of the proposed method is evaluated using a set of in vivo experiment data. Copyright © 2012 Elsevier Ltd. All rights reserved.
Geometry and time scales of self-consistent orbits in a modified SU(2) model
International Nuclear Information System (INIS)
Jezek, D.M.; Hernandez, E.S.; Solari, H.G.
1986-01-01
We investigate the time-dependent Hartree-Fock flow pattern of a two-level many fermion system interacting via a two-body interaction which does not preserve the parity symmetry of standard SU(2) models. The geometrical features of the time-dependent Hartree-Fock energy surface are analyzed and a phase instability is clearly recognized. The time evolution of one-body observables along self-consistent and exact trajectories are examined together with the overlaps between both orbits. Typical time scales for the determinantal motion can be set and the validity of the time-dependent Hartree-Fock approach in the various regions of quasispin phase space is discussed
International Nuclear Information System (INIS)
Avci, D.
2005-01-01
The molecular geometry and vibrational frequencies of 4,5-bis-(2-isopropyl-5- methylphenoxy) phthalonitrile in the ground state have been calculated using the Hartree- Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of 4,5-bis-(2-isopropyl-5-methylphenoxy) phthalonitrile with calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems
International Nuclear Information System (INIS)
Kurt, M.
2005-01-01
The molecular geometry and vibrational frequencies of 6-methylquinoline(6MQ) and 8-methylquinolines(8MQ) in the ground state have been calculated by using the Hartree-Fock and density functional methods (B3LYP and BLYP) with 6-31G (d) as the basis set. The optimized geometric bond lengths obtained by using B3LYP and bond angles obtained by BLYP were given corresponding experimental values of similar molecule. Comparison of the observed fundamental vibrational frequencies of these molecules and calculated results by density functional B3LYP, BLYP and Hartree-Fock methods indicates that B3LYP is superior to the scaled Hartree- Fock and BLYP approach for molecular vibrational problems
Optimised Environmental Test Approaches in the GOCE Project
Ancona, V.; Giordano, P.; Casagrande, C.
2004-08-01
The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) is dedicated to measuring the Earth's gravity field and modelling the geoid with extremely high accuracy and spatial resolution. It is the first Earth Explorer Core mission to be developed as part of ESA's Living Planet Programme and is scheduled for launch in 2006. The program is managed by a consortium of European companies: Alenia Spazio, the prime contractor, Astrium GmbH, the platform responsible, Alcatel Space Industries and Laben, suppliers of the main payloads, respectively the Electrostatic Gravity Gradiometer (EGG) and the Satellite to Satellite Tracking Instrument (SSTI), actually a precise GPS receiver. The GOCE Assembly Integration and Verification (AIV) approach is established and implemented in order to demonstrate to the customer that the satellite design meets the applicable requirements and to qualify and accept from lower level up to system level. The driving keywords of "low cost" and "short schedule" program, call for minimizing the development effort by utilizing off-the-shelf equipment combined with a model philosophy lowering the number of models to be used. The paper will deal on the peculiarities of the optimized environmental test approach in the GOCE project. In particular it introduces the logic of the AIV approach and describe the foreseen tests at system level within the SM environmental test campaign, outlining the Quasi Static test performed in the frame of the SM sine vibration tests, and the PFM environmental test campaign pinpointing the deletion of the Sine Vibration test on PFM model. Furthermore the paper highlights how the Model and Test Effectiveness Database (MATD) can be utilized for the prediction of the new space projects like GOCE Satellite.
A microscopic description of nuclear shapes
International Nuclear Information System (INIS)
Bonche, P.
1987-07-01
This talk describes recent three-dimensional self-consistent Hartree-Fock calculations. After an introduction providing the basic approximations and the different symmetries, we present an application to quadrupole deformation. We pursue with a study of octupole deformation properties of 222 Ra and 144 Ba nuclei for which states of good (positive and negative) parity are projected out. Finally we discuss an extension to the study of rotation and high-spin states with the cranked self-consistent Hartree-Fock method. As an example, the 24 Mg nucleus is studied as a function of angular momentum from ground state up to fission
Integrating a Project Management Approach to E-Business Application Course
Chen, Kuan C.; Chuang, Keh-Wen
2008-01-01
Teaching students project managements requires a hands-on approach. Incorporating project management concepts and processes into a student team Web development project adds a dimension that exposes students to the realities of effective Web development. This paper will describe the project management approach used in a Web development course in…
NNP-LANL Utilities - Condition Assessment and Project Approach
Energy Technology Data Exchange (ETDEWEB)
Stewart, Grant Lorenz [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-11-21
This report is a presentation on LANL Utilities & Transportation Asset Management; Utility Assets Overview; Condition Assessment; Utilities Project Nominations & Ranking; and Utilities Project Execution.
Microscopic description of low-energy nuclear collisions: review and perspective
International Nuclear Information System (INIS)
Bonche, Paul
2000-01-01
The primary goal of this lecture is a review of the microscopic approaches to nuclear reactions. Semi-phenomenological theories will not be discussed. First the Time-Dependent Hartree-Fock formalism is recalled. The effective nucleon-nucleon interactions used in TDHF calculations are discussed. Applications to collisions are presented in different approximation scheme, one-dimensional dynamics, approximate three-dimensional ones.... Finally two microscopic extensions beyond mean-field are reviewed: the variational principal of Balian and Veneroni and the implementation of residual two-body interactions in the Time-Dependent Density Matrix (TDDM) and the Extended Time-Dependent Hartree-Fock schemes (ET-DHF). (author)
Computational approaches in the design of synthetic receptors – A review
Energy Technology Data Exchange (ETDEWEB)
Cowen, Todd, E-mail: tc203@le.ac.uk; Karim, Kal; Piletsky, Sergey
2016-09-14
The rational design of molecularly imprinted polymers (MIPs) has been a major contributor to their reputation as “plastic antibodies” – high affinity robust synthetic receptors which can be optimally designed, and produced for a much reduced cost than their biological equivalents. Computational design has become a routine procedure in the production of MIPs, and has led to major advances in functional monomer screening, selection of cross-linker and solvent, optimisation of monomer(s)-template ratio and selectivity analysis. In this review the various computational methods will be discussed with reference to all the published relevant literature since the end of 2013, with each article described by the target molecule, the computational approach applied (whether molecular mechanics/molecular dynamics, semi-empirical quantum mechanics, ab initio quantum mechanics (Hartree-Fock, Møller–Plesset, etc.) or DFT) and the purpose for which they were used. Detailed analysis is given to novel techniques including analysis of polymer binding sites, the use of novel screening programs and simulations of MIP polymerisation reaction. The further advances in molecular modelling and computational design of synthetic receptors in particular will have serious impact on the future of nanotechnology and biotechnology, permitting the further translation of MIPs into the realms of analytics and medical technology. - Highlights: • A review of computational modelling in the design of molecularly imprinted polymers. • Target analytes and method of analysis for the vast majority of recent articles. • Explanations are given of all the popular and emerging techniques used in design. • Highlighted examples of sophisticated analysis of imprinted polymer systems.
Computational approaches in the design of synthetic receptors – A review
International Nuclear Information System (INIS)
Cowen, Todd; Karim, Kal; Piletsky, Sergey
2016-01-01
The rational design of molecularly imprinted polymers (MIPs) has been a major contributor to their reputation as “plastic antibodies” – high affinity robust synthetic receptors which can be optimally designed, and produced for a much reduced cost than their biological equivalents. Computational design has become a routine procedure in the production of MIPs, and has led to major advances in functional monomer screening, selection of cross-linker and solvent, optimisation of monomer(s)-template ratio and selectivity analysis. In this review the various computational methods will be discussed with reference to all the published relevant literature since the end of 2013, with each article described by the target molecule, the computational approach applied (whether molecular mechanics/molecular dynamics, semi-empirical quantum mechanics, ab initio quantum mechanics (Hartree-Fock, Møller–Plesset, etc.) or DFT) and the purpose for which they were used. Detailed analysis is given to novel techniques including analysis of polymer binding sites, the use of novel screening programs and simulations of MIP polymerisation reaction. The further advances in molecular modelling and computational design of synthetic receptors in particular will have serious impact on the future of nanotechnology and biotechnology, permitting the further translation of MIPs into the realms of analytics and medical technology. - Highlights: • A review of computational modelling in the design of molecularly imprinted polymers. • Target analytes and method of analysis for the vast majority of recent articles. • Explanations are given of all the popular and emerging techniques used in design. • Highlighted examples of sophisticated analysis of imprinted polymer systems.
International project marketing: an introduction to the INPM approach
DEFF Research Database (Denmark)
Skaates, Maria Anne; Tikkanen, Henrikki
2003-01-01
marketing takes place. First, we discuss various definitions of projects and project marketing. Second, we consider the implications of three specific features of project business--discontinuity, uniqueness, and complexity--over multiple projects. Third, we assess three overlapping types of postures......Projects are often sold and procured. Therefore this paper reviews recent contributions of the International Network for Project Marketing and Systems Selling (INPM), emphasising the connection between the business relationships of individual projects and the wider environment in which project...... that project-selling firms can adopt in relation to their marketing activities. Finally, we make some suggestions for practitioners responsible for marketing projects and discuss avenues for future academic work in project marketing....
Project Report on Development of a Safeguards Approach for Pyroprocessing
Energy Technology Data Exchange (ETDEWEB)
Robert Bean
2010-09-01
The Idaho National Laboratory has undertaken an effort to develop a standard safeguards approach for international commercial pyroprocessing facilities. This report details progress for the fiscal year 2010 effort. A component by component diversion pathway analysis has been performed, and has led to insight on the mitigation needs and equipment development needed for a valid safeguards approach. The effort to develop an in-hot cell detection capability led to the digital cloud chamber, and more importantly, the significant potential scientific breakthrough of the inverse spectroscopy algorithm, including the ability to identify energy and spatial location of gamma ray emitting sources with a single, non-complex, stationary radiation detector system. Curium measurements were performed on historical and current samples at the FCF to attempt to determine the utility of using gross neutron counting for accountancy measurements. A solid cost estimate of equipment installation at FCF has been developed to guide proposals and cost allocations to use FCF as a test bed for safeguards measurement demonstrations. A combined MATLAB and MCNPX model has been developed to perform detector placement calculations around the electrorefiner. Early harvesting has occurred wherein the project team has been requested to provide pyroprocessing technology and safeguards short courses.
Applying a life cycle approach to project management methods
Biggins, David; Trollsund, F.; Høiby, A.L.
2016-01-01
Project management is increasingly important to organisations because projects are the method\\ud by which organisations respond to their environment. A key element within project management\\ud is the standards and methods that are used to control and conduct projects, collectively known as\\ud project management methods (PMMs) and exemplified by PRINCE2, the Project Management\\ud Institute’s and the Association for Project Management’s Bodies of Knowledge (PMBOK and\\ud APMBOK. The purpose of t...
Nonnegative least-squares image deblurring: improved gradient projection approaches
Benvenuto, F.; Zanella, R.; Zanni, L.; Bertero, M.
2010-02-01
The least-squares approach to image deblurring leads to an ill-posed problem. The addition of the nonnegativity constraint, when appropriate, does not provide regularization, even if, as far as we know, a thorough investigation of the ill-posedness of the resulting constrained least-squares problem has still to be done. Iterative methods, converging to nonnegative least-squares solutions, have been proposed. Some of them have the 'semi-convergence' property, i.e. early stopping of the iteration provides 'regularized' solutions. In this paper we consider two of these methods: the projected Landweber (PL) method and the iterative image space reconstruction algorithm (ISRA). Even if they work well in many instances, they are not frequently used in practice because, in general, they require a large number of iterations before providing a sensible solution. Therefore, the main purpose of this paper is to refresh these methods by increasing their efficiency. Starting from the remark that PL and ISRA require only the computation of the gradient of the functional, we propose the application to these algorithms of special acceleration techniques that have been recently developed in the area of the gradient methods. In particular, we propose the application of efficient step-length selection rules and line-search strategies. Moreover, remarking that ISRA is a scaled gradient algorithm, we evaluate its behaviour in comparison with a recent scaled gradient projection (SGP) method for image deblurring. Numerical experiments demonstrate that the accelerated methods still exhibit the semi-convergence property, with a considerable gain both in the number of iterations and in the computational time; in particular, SGP appears definitely the most efficient one.
Reinventing project management the diamond approach to successful growth & innovation
Shenhar, Aaron J.
2007-01-01
Projects are the engines that drive innovation from idea to commercialization. In fact, the number of projects in most organizations today is expanding while operations is shrinking. Yet, since many companies still focus on operational excellence and efficiency, most projects fail--largely because conventional project management concepts cannot adapt to a dynamic business environment. Moreover, top managers neglect their company's project activity, and line managers treat all their projects alike--as part of operations. Based on an unprecedented study of more than 600 projects in a variety of businesses and organizations around the globe, "Reinventing Project Management" provides a new and highly adaptive model for planning and managing projects to achieve superior business results.
Directory of Open Access Journals (Sweden)
Anna Osello
2013-12-01
Full Text Available Design, implementation and management constitute the cornerstones of the building process and the current trend, albeit still at an embryonic state in Italy, is represented by the application of a problem-solving approach combining integrated analysis and research between interdisciplinary professionals able to integrate their know-how and experience. The project SEEMPubS (Smart Energy Efficient Middleware for Public Spaces, which ended in August 2013, investigated the theoretical and operational possibility of using a network of sensors to monitor energy consumption and raise awareness of this issue among end-users in academic and working places. The project DIMMER (District Information Modeling and Management for Energy Reduction, that kicked off on October 01st, 2013, represents its evolution, as the research extends from buildings (building scale to the neighborhood (urban scale, simultaneously expanding the areas of study. Data and information to be processed and analyzed call, in this case, for a reconsideration of the activities to be carried out, through the use of innovative instruments and procedures to ensure correct information flow and optimal data management. For this purpose, we adopted the BIM methodology (Building Information Modeling for digital representation and modeling of our case studies, facility management and analysis of interoperability between different software applications, investigating how the tools currently available on the market and the interdisciplinary collaboration between professionals from different areas may constitute the standard for tomorrow’s communication.
Sustainability: An Ethical Approach Towards Project Business Success
G. S. Dangayach
2011-01-01
For any country the project management has been a vital part for its development. The highly competitive business world has created tremendous pressure on the project managers to achieve success. The pressure is derived from survival and profit building in business organizations which compels the project managers to pursue unethical practices. As a result unethical activities in business projects can be found easily where situations or issues arise due to dubious business...
Progress of IFERC project in the Broader Approach Activities
International Nuclear Information System (INIS)
Araki, M.; Sakamoto, Y.; Hayashi, K.; Ohuchi, R.; Nishitani, T.
2010-01-01
For contributing to the ITER project and promoting a possible early realization of DEMO, since 2007 the International Fusion Energy Research Centre (IFERC) shall perform the activities on (1) DEMO Design and R and D Coordination, (2) Computational Simulation Centre, and (3) ITER Remote Experimentation Centre in the framework under the agreement between the Government of Japan and the European Atomic Energy Community for the joint implementation of the Broader Approach Activities in the field of fusion energy. The DEMO Design activity aims at establishing a common basis for DEMO Design, including design features of DEMO, possible common concepts of DEMO, a roadmap for DEMO, and so on. Based on the common interest of EU and Japan toward DEMO, the DEMO R and D activities have been planned and carried out for the areas which are related to DEMO blanket development: SiC/SiC composites, tritium technology, materials engineering, advanced neutron multiplier, and advanced tritium breeders for DEMO blanket. In the activity of the Computational Simulation Centre, the objective is to provide and exploit a supercomputer for large scale simulation activities to analyse experimental data on fusion plasmas, prepare scenarios for ITER operation, predict the performance of the ITER facilities and contribute to the DEMO Design.
A hierarchical approach to multi-project planning under uncertainty
Leus, R.; Wullink, Gerhard; Hans, Elias W.; Herroelen, W.
2004-01-01
We survey several viewpoints on the management of the planning complexity of multi-project organisations under uncertainty. A positioning framework is proposed to distinguish between different types of project-driven organisations, which is meant to aid project management in the choice between the
El Metodo Llamado Proyecto (The Project Approach). ERIC Digest.
Katz, Lilian G.
A project is an in-depth investigation of a topic worth learning more about, usually undertaken by a group of children within a class. The goal of a project is to learn more about a topic rather than to find answers to questions posed by a teacher. Project work is complementary to the systematic parts of a curriculum. Whereas systematic…
A hierarchical approach to multi-project planning under uncertainty
Hans, Elias W.; Herroelen, W.; Wullink, Gerhard; Leus, R.
2007-01-01
We survey several viewpoints on the management of the planning complexity of multi-project organisations under uncertainty. Based on these viewpoints we propose a positioning framework to distinguish between different types of project-driven organisations. This framework is meant to aid project
TARGET APPROACH TO PROJECT FINANCING TRANCHES OF INNOVATIONS AND INVESTMENTS
Directory of Open Access Journals (Sweden)
Galina G. Balayan
2015-01-01
Full Text Available The article concerns the main provisions of the financing tranches for innovative projects. The article is of methodological nature. It gives theoretically justified, universal for any of the project stages and their characteristics needed to calculate efficiency project financing tranches.
How project approach influences adoption of SWC by farmers, examples from southern Mali
Bodnar, F.; Schrader, T.; Campen, Van W.
2006-01-01
Choices in project approach affect the continuation of soil and water conservation (SWC) after project withdrawal, and thus the sustainability and cost effectiveness of the project. A SWC project was carried out in southern Mali between 1986 and 1998. Its features were the promotion of cheap and
Projection operator approach to the self-energy
International Nuclear Information System (INIS)
Capuzzi, F.; Mahaux, C.
1996-01-01
Feshbach close-quote s projection operator formalism is extended to the description of the self-energy. This necessitates the introduction of open-quote open-quote extended close-quote close-quote projection operators. They act within an open-quote open-quote extended close-quote close-quote Hilbert space in which the number of nucleons is not fixed. The compact formula derived for the self-energy is formally similar to Feshbach close-quote s original expression of the open-quote open-quote generalized close-quote close-quote optical-model potential. The theory is formulated in the nuclear case, but it also applies to atomic systems. It covers both the open-quote open-quote retarded close-quote close-quote and the open-quote open-quote time-ordered close-quote close-quote Green close-quote s functions, and the open-quote open-quote proper close-quote close-quote and open-quote open-quote improper close-quote close-quote self-energies. It is first worked out in a stationary formalism, in order to better exhibit its analogy with Feshbach close-quote s original theory of the generalized optical-model potential. The main results are then also derived in a time-dependent framework. It is shown that, in finite systems, Dyson close-quote s equation does not uniquely determine the self-energy, in contrast to common assumption. However, the difference between the various possibilities has little practical consequence. We exhibit the relationship between the present approach and a recent open-quote open-quote configuration interaction formulation of the Dyson equation.close-quote close-quote Contact is also established with the open-quote open-quote linked-cluster close-quote close-quote perturbation expansion of the self-energy in powers of the strength of the nucleon endash nucleon interaction. Copyright copyright 1996 Academic Press, Inc
Holmes, Monica C.; Jenicke, Lawrence O.; Hempel, Jessica L.
2015-01-01
Purpose: This paper discusses the importance of the Six Sigma selection process, describes a Six Sigma project in a higher educational institution and presents a weighted scorecard approach for project selection. Design/Methodology/Approach: A case study of the Six Sigma approach being used to improve student support at a university computer help…
Rusman, Ellen; Rajagopal, Kamakshi; Stoyanov, Slavi; Van Maele, Jan
2011-01-01
Rusman, E., Rajagopal, K., Stoyanov, S., & Van Maele, J. (2011, 20-21 October). Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case. Paper presented at the 4th International Conference ICT for Language Learning, Florence, Italy.
Rusman, Ellen; Rajagopal, Kamakshi; Stoyanov, Slavi; Van Maele, Jan
2011-01-01
Rusman, E., Rajagopal, K., Stoyanov, S., & Van Maele, J. (2011, 20-21 October). Exploration of Exploitation Approaches of European Projects on ICT and Foreign Language Learning: the CEFcult project case. Paper presented at the 4th International Conference ICT for Language Learning, Florence, Italy. Available at: http://www.pixel-online.net/ICT4LL2011/conferenceproceedings.php
Adhi Cahyono; Yanki Hartijasti
2012-01-01
Conflict can be functional or dysfunctional to the organization’s performance. This study focused on the relationship between conflict approaches implemented by the project manager based on project team member’s perception on the effectiveness of the project manager in managing project’s conflict. Questionnaires were modified from Barker et al. (1988) to measure conflict management approaches and outcomes of managing project conflict. Data were gathered from 57 respondents w...
Directory of Open Access Journals (Sweden)
Aliyeh Kazemi
2016-09-01
Full Text Available Construction projects have always been complex. By growing trend of this complexity, implementations of large-scale constructions become harder. Hence, evaluating and understanding these complexities are critical. Correct evaluation of a project complication can provide executives and managers with good source to use. Fuzzy analytic network process (ANP is a logical and systematic approach toward defining, evaluation, and grading. This method allows for analyzing complex systems, and determining complexity of them. In this study, by taking advantage of fuzzy ANP, effective indexes for development of complications in large-scale construction projects in Iran have been determined and prioritized. The results show socio-political, project system interdependencies, and technological complexity indexes ranked top to three. Furthermore, in comparison of three main huge projects: commercial-administrative, hospital, and skyscrapers, the hospital project had been evaluated as the most complicated. This model is beneficial for professionals in managing large-scale projects.
International Nuclear Information System (INIS)
Da Rocha, C.A.; Wilets, L.
1997-01-01
Complex mass poles, or ghost poles, are present in the Hartree-Fock solution of the Schwinger-Dyson equation for the nucleon propagator in renormalizable models with Yukawa-type meson-nucleon couplings, as shown many years ago by Brown, Puff and Wilets (BPW). These ghosts violate basic theorems of quantum field theory and their origin is related to the ultraviolet behavior of the model interactions. Recently, Krein et.al, proved that the ghosts disappear when vertex corrections are included in a self-consistent way, softening the interaction sufficiently in the ultraviolet region. In previous studies of πN scattering using ''dressed'' nucleon propagator and bare vertices, did by Nutt and Wilets in the 70's (NW), it was found that if these poles are explicitly included, the value of the isospin-even amplitude A (+) is satisfied within 20% at threshold. The absence of a theoretical explanation for the ghosts and the lack of chiral symmetry in these previous studies led us to re-investigate the subject using the approach of the linear σ-model and study the interplay of low-energy theorems for πN scattering and ghost poles. For bare interaction vertices we find that ghosts are present in this model as well and that the A (+) value is badly described. As a first approach to remove these complex poles, we dress the vertices with phenomenological form factors and a reasonable agreement with experiment is achieved. In order to fix the two cutoff parameters, we use the A (+) value for the chiral limit (m π →0) and the experimental value of the isoscalar scattering length. Finally, we test our model by calculating the phase shifts for the S waves and we find a good agreement at threshold. (orig.)
Isospin Mixing in Nuclei Around N ∼ Z and the Superallowed β-Decay
International Nuclear Information System (INIS)
Satula, W.; Dobaczewski, J.; Nazarewicz, W.; Rafalski, M.
2011-01-01
Theoretical approaches that use one-body densities as dynamical variables, such as Hartree-Fock or the density functional theory (DFT), break isospin symmetry both explicitly, by virtue of charge-dependent interactions, and spontaneously. To restore the spontaneously broken isospin symmetry, we implemented the isospin-projection scheme on top of the Skyrme-DFT approach. This development allows for consistent treatment of isospin mixing in both ground and exited nuclear states. In this study, we apply this method to evaluate the isospin impurities in ground states of even-even and odd-odd N ∼ Z nuclei. By including simultaneous isospin and angular-momentum projection, we compute the isospin-breaking corrections to the 0 + → 0 + superallowed β-decay. (authors)
Consistent microscopic theory of collective motion in the framework of an ATDHF approach
International Nuclear Information System (INIS)
Goeke, K.; Reinhard, P.
1978-01-01
Based on merely two assumptions, namely the existence of a collective Hamiltonian and that the collective motion evolves along Slater determinants, we first derive a set of adiabatic time-dependent Hartree-Fock equations (ATDHF) which determine the collective path, the mass and the potential, second give a unique procedure for quantizing the resulting classical collective Hamiltonian, and third explain how to use the collective wavefunctions, which are eigenstates of the quantized Hamiltonian
Energy Technology Data Exchange (ETDEWEB)
Feller, D.F.
1979-01-01
The behavior of the two exponential parameters in an even-tempered gaussian basis set is investigated as the set optimally approaches an integral transform representation of the radial portion of atomic and molecular orbitals. This approach permits a highly accurate assessment of the Hartree-Fock limit for atoms and molecules.
Some comments about the binding interpretation of the EMC effect
International Nuclear Information System (INIS)
Chanfray, G.
1990-01-01
The effect of binding on the nuclear structure function F 2A , deduced from effective Hartree-Fock theory is much smaller than the result obtained from a microscopic approach including correlations. We show that the contradiction between these two types of conventional nuclear approaches is to a large extent, only apparent since they do not refer to the same degrees of freedom
Sizing ERP implementation projects: an activity-based approach
Janssens, G.; Kusters, R.J.; Heemstra, F.J.
2008-01-01
ERP implementation projects affect large parts of an implementing organization and lead to changes in the way an organization performs its tasks. The costs needed for the effort to implement these systems are hard to estimate. Research indicates that the size of an ERP project can be a useful
A fuzzy hybrid approach for project manager selection
Directory of Open Access Journals (Sweden)
Ahmad Jafarnejad Chaghooshi
2016-09-01
Full Text Available Suitable project manager has a significant impact on successful accomplishment of the project. Managers should possess such skills in order to effectively cope with the competition. In this respect, selecting managers based on their skills can lead to a competitive advantage towards the achievement of organizational goals. selection of the suitable project manager can be viewed as a multi-criteria decision making (MCDM problem and an extensive evaluation of criteria, such as Technical skills, experience skills, Personal qualities and the related criteria must be considered in the selection process of project manager. The fuzzy set theory and MCDM methods appears as an essential tools to provide a decision framework that incorporates imprecise judgments and multi criteria nature of project manager selection process inherent in this process. This paper proposes the joint use of the Fuzzy DEMATEL (FDEMATEL and Fuzzy VIKOR methods for the decision-making process of selecting the most suitable managers for projects. First, with the opinions of the senior managers based on project management competency model (ICB-IPMA, all the criteria required for the selection are gathered. Then the FDEMATEL method is used to prioritize the importance of various criteria and FVIKOR used to rank the alternatives in a preferred order to select the best project managers from a number of alternatives. Next, a real case study used to illustrate the process of the proposed method. Finally, some conclusions are discussed at the end of this study.
An Applied Project-Driven Approach to Undergraduate Research Experiences
Karls, Michael A.
2017-01-01
In this paper I will outline the process I have developed for conducting applied mathematics research with undergraduates and give some examples of the projects we have worked on. Several of these projects have led to refereed publications that could be used to illustrate topics taught in the undergraduate curriculum.
The Project-Based Learning Approach in Environmental Education
Genc, Murat
2015-01-01
The purpose of this study is to investigate the effect of project-based learning on students' attitudes toward the environment. In the study that was performed with 39 students who take the "Environmental Education" course, attitude changes toward the environment were investigated in students who developed projects on environmental…
Systemwide Implementation of Project-Based Learning: The Philadelphia Approach
Schwalm, Jason; Tylek, Karen Smuck
2012-01-01
Citywide implementation of project-based learning highlights the benefits--and the challenges--of promoting exemplary practices across an entire out-of-school time (OST) network. In summer 2009, the City of Philadelphia and its intermediary, the Public Health Management Corporation (PHMC), introduced project-based learning to a network of more…
Investigation of high spin structure of N ∼ 28 nuclei with PHF model
International Nuclear Information System (INIS)
Naik, Z.
2016-01-01
Nucleus in 50 mass shows verity of high spin phenomena. Some of them are K-Isomer, Band termination, States Beyond Band termination, Superdeformed Structure, Shape co-existence and many more. Some of these phenomena with Projected Hartree-Fock (PHF) model are addressed and the microscopic structure associate with them is discussed
Liu Ying Tai
2002-01-01
The approximate angular-momentum-projected Hartree-Fock (PDHF) method is used to study some odd-A nuclei in the 3s-2d-1g shell: sup 1 sup 1 sup 5 sup - sup 1 sup 2 sup 3 I. Their ground bands and low excited bands are calculated. The calculated results agree well with the experimental spectrum
How to Grow Project Scientists: A Systematic Approach to Developing Project Scientists
Kea, Howard
2011-01-01
The Project Manager is one of the key individuals that can determine the success or failure of a project. NASA is fully committed to the training and development of Project Managers across the agency to ensure that highly capable individuals are equipped with the competencies and experience to successfully lead a project. An equally critical position is that of the Project Scientist. The Project Scientist provides the scientific leadership necessary for the scientific success of a project by insuring that the mission meets or exceeds the scientific requirements. Traditionally, NASA Goddard project scientists were appointed and approved by the Center Science Director based on their knowledge, experience, and other qualifications. However the process to obtain the necessary knowledge, skills and abilities was not documented or done in a systematic way. NASA Goddard's current Science Director, Nicholas White saw the need to create a pipeline for developing new projects scientists, and appointed a team to develop a process for training potential project scientists. The team members were Dr. Harley Thronson, Chair, Dr. Howard Kea, Mr. Mark Goldman, DACUM facilitator and the late Dr. Michael VanSteenberg. The DACUM process, an occupational analysis and evaluation system, was used to produce a picture of the project scientist's duties, tasks, knowledge, and skills. The output resulted in a 3-Day introductory course detailing all the required knowledge, skills and abilities a scientist must develop over time to be qualified for selections as a Project Scientist.
Directory of Open Access Journals (Sweden)
Adhi Cahyono
2012-10-01
Full Text Available Conflict can be functional or dysfunctional to the organization’s performance. This study focused on the relationship between conflict approaches implemented by the project manager based on project team member’s perception on the effectiveness of the project manager in managing project’s conflict. Questionnaires were modified from Barker et al. (1988 to measure conflict management approaches and outcomes of managing project conflict. Data were gathered from 57 respondents who worked in the Engineering, Procurement, and Construction (EPC contractors serving the upstream sector of the Oil and Gas industry in Indonesia. By using Pearson correlation, result of this study indicated that project managers were perceived to be effective in managing project conflict when implementing cooperative and confi rmative approaches, but ineffective when combining competitive and avoidance approaches. Further research should investigate correlation between cultural dimensions with conflict approaches and outcomes of managing conflict.
METHOD FOR SELECTION OF PROJECT MANAGEMENT APPROACH BASED ON FUZZY CONCEPTS
Directory of Open Access Journals (Sweden)
Igor V. KONONENKO
2017-03-01
Full Text Available Literature analysis of works that devoted to research of the selection a project management approach and development of effective methods for this problem solution is given. Mathematical model and method for selection of project management approach with fuzzy concepts of applicability of existing approaches are proposed. The selection is made of such approaches as the PMBOK Guide, the ISO21500 standard, the PRINCE2 methodology, the SWEBOK Guide, agile methodologies Scrum, XP, and Kanban. The number of project parameters which have a great impact on the result of the selection and measure of their impact is determined. Project parameters relate to information about the project, team, communication, critical project risks. They include the number of people involved in the project, the customer's experience with this project team, the project team's experience in this field, the project team's understanding of requirements, adapting ability, initiative, and others. The suggested method is considered on the example of its application for selection a project management approach to software development project.
TARGETED APPROACH TO MANAGING THE FINANCING OF INNOVATIVE PROJECTS
Directory of Open Access Journals (Sweden)
G. G. Balayan
2014-01-01
Full Text Available The variant of financing the innovative project that allows you to structure any project on the standard stages, regardless of the content of the project. For decision makers, in the management system information is narrowed to a necessary and sufficient by the correct selection of data. The necessity of timely forecast of problem situations and liquidation of not bringing to the state of the problem. It is proposed to organize the state structure, the Bank of innovations, concentrating innovations and connecting inventors with investors and customers.
Project approach in enterprise management in Kazakhstan
Directory of Open Access Journals (Sweden)
Berdykulova G. M.
2016-03-01
Full Text Available the article is dedicated to study the advanced case of small business of Kazakhstan on reorganization of organizational structure in accord with the methodology of Project Management Body of Knowledge (PMBOK.
[Life project of residents and institutional approach in nursing homes].
Chanut, Corinne
The life project in a nursing home involves all the players concerned: first of all, the resident, then the caregivers, the families and the institution. This unifying tool, organised around the elderly, helps to develop collective competencies, favours the integration of new residents and reassures families. This article presents a nursing home's experience of setting up a life project. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
An Agent Based Approach for Project Management in Construction
Sencer, Safiye; Turgay, Tahsin
2013-01-01
Project management has an important role in terms of time, cost and flexibility. An agentbased architecture provides additional robustness, scalability, flexibility that is particularly appropriate for problems with a dynamic and distributed nature. Integrated agent based project management covers design and construction planning. It is combined with plan execution, tolerating both the design and plan, which may be changed as necessary. In this reason, the decision making process requires tha...
Microscopic evaluation of the nuclear dipole polarizability
Energy Technology Data Exchange (ETDEWEB)
Lipparini, E; Orlandini, G; Stringari, S; Traini, M [Trento Univ. (Italy). Dept. di Matematica e Fisica
1977-12-01
The dipole polarizability sum rule has been evaluated by means of a restricted Hartree-Fock approach. The method leads to a simple and analytical expression for the dipole polarizability. Explicit calculations have been performed in /sup 16/O and /sup 40/Ca with different types of interaction.
Ground state phase diagram of extended attractive Hubbard model
International Nuclear Information System (INIS)
Robaszkiewicz, S.; Chao, K.A.; Micnas, R.
1980-08-01
The ground state phase diagram of the extended Hubbard model with intraatomic attraction has been derived in the Hartree-Fock approximation formulated in terms of the Bogoliubov variational approach. For a given value of electron density, the nature of the ordered ground state depends essentially on the sign and the strength of the nearest neighbor coupling. (author)
DEFF Research Database (Denmark)
Jensen, Lars; Mortensen, Peter Mølgaard; Trane, Rasmus
2009-01-01
functional theory (DFT)/Hartree-Fock approach. It was not possible from this to assess with certainty which intermediate products formed most extensively in an acetone/hydrogen peroxide mixture. However, it was concluded that the most likely reaction mixture is a mixture of the different intermediate...
Isospin-dependent term in the relativistic microscopic optical potential
International Nuclear Information System (INIS)
Rong Jian; Ma Zhongyu; National Laboratory of Heavy Ion Accelerator of Lanzhou, Lanzhou; Chinese Academy of Sciences, Beijing
2005-01-01
The isospin-dependence of the relativistic microscopic optical potential is investigated in the Dirac Brueckner-Hartree-Fock approach. The isospin part of the microscopic optical potential is emphasized. A local density approximation is adopted for finite nuclei. Taking 208 Pb as example, the difference between proton and neutron optical potentials is studied and compared with the phenomenological Lane Model potential. (authors)
Raj Kumar Chopra; Varun Gupta; Durg Singh Chauhan
2016-01-01
Non functional requirements must be selected for implementation together with functional requirements to enhance the success of software projects. Three approaches exist for performing the prioritization of non functional requirements using the suitable prioritization technique. This paper performs experimentation on three different complexity versions of the industrial software project using cost-value prioritization technique employing three approaches. Experimentation is conducted to analy...
An approach to establishing cooperative R ampersand D projects with Russian Institutes
International Nuclear Information System (INIS)
Hunter, T.; Albert, T.; Fryberger, T.; Romanovsky, V.
1993-01-01
An important part of technology exchange between the US and the former Soviet Union is the identification and implementation of cooperative projects that benefit both Russia and the US. The US Department of Energy and its laboratories have established an approach to identify potential technologies that can contribute to solving US environmental problems and to establish projects for enhancing technology development. This approach consists of screening technologies for US applications, conducting small-scale pilot projects with Russian scientists to evaluate the validity of mechanisms for larger projects, helping develop direct communication between US and Russian scientists who are developing these technologies, and implementing major projects in specific technology development areas. A recent example of this approach is the initiation of projects between the Khlopin Radium Institute and DOE through Sandia National Laboratories and SAIC. This effort has resulted in not only enhanced technology for the US but has also provided an example for future cooperative projects
International Nuclear Information System (INIS)
Zaider, M.
1997-01-01
The goal of this project was to develop theoretical/computational tools for evaluating the risks incurred by populations exposed to radon alpha particles. Topics of concern include the following: compound dual radiation action (general aspects); a mathematical formalism describing the yield of radiation induced single-and double-strand DNA breaks, and its dependence on radiation quality; a study of the excited states in cytosine and guanine stacks in the Hartree-Fock and exciton approximations; nanodosimetry of radon alpha particles; application of the HSEF to assessing radiation risks in the practice of radiation protection; carcinogenic risk coefficients at environmental levels of radon exposures: a microdosimetric approach; and hit-size effectiveness approach in radiation protection
Microscopic study of superdeformed rotational bands in {sup 151} Tb
Energy Technology Data Exchange (ETDEWEB)
El Aouad, N.; Dudek, J.; Li, X.; Luo, W.D.; Molique, H.; Bouguettoucha, A.; Byrski, TH.; Beck, F.; Finck, C.; Kharraja, B. [Strasbourg-1 Univ., 67 (France). Centre de Recherches Nucleaires; Dobaczewski, J. [Warsaw Univ. (Poland); Kharraja, B. [Notre Dame Univ., IN (United States). Dept. of Physics
1996-12-31
Structure of eight superdeformed bands in the nucleus {sup 151}Tb is analyzed using the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is demonstrated that far going similarities between the two approaches exit and predictions related to the structure of rotational bands calculated within the two models are nearly parallel. An interpretation scenario for the structure of the superdeformed bands is presented and predictions related to the exit spins are made. Small but systematic discrepancies between experiment and theory, analyzed in terms of the dynamical moments, J{sup (2)}, are shown to exist. The pairing correlations taken into account by using the particle-number-projection technique are shown to increase the disagreement. Sources of these systematic discrepancies are discussed - they are most likely related to the yet not optimal parametrization of the nuclear interactions used. (authors). 60 refs.
Defining Investment Additionality for CDM projects - practical approaches
International Nuclear Information System (INIS)
Greiner, Sandra; Michaelowa, Axel
2003-01-01
The environmental integrity of the CDM under the Kyoto Protocol depends on the possibility to avoid giving emission credits to projects that would have happened anyway. Whether and how 'Investment Additionality' of CDM projects has to be determined is currently a part of climate negotiations. We discuss the rationale of companies to invest in projects and analyse possible criteria to determine Investment Additionality from a theoretical point of view. Differences in the type of investment call for the application of different criteria. Although some criteria are better than others, no single criterion can outweigh the others in all respects. We therefore suggest a scheme for additionality testing that aims at matching types of investment and criteria in a sensible way. Criteria are evaluated on the grounds of robustness to manipulation, degree of coverage and appropriateness for testing the investment decision under consideration
Development of Entrepreneurship Competences from Project Based Learning Approaches
Directory of Open Access Journals (Sweden)
Lidia SÁNCHEZ GONZÁLEZ
2017-02-01
Full Text Available A key issue for any educational institution is to train individuals in such a way that they participate efficiently in their context. The current context where learning is carried out is digital era. With this landscape, and taking into account the current socioeconomic situation, it is necessary to increase students’ employability. This requires that what is taught in educational institutions fits with companies’ requirements. In this sense one of most common companies’ requirement is that students have knowledge about how to develop a project from scratch. In order to address this issue, the present paper poses the application of a project based learning methodology. This methodology is applied in an experiment that comprises two academic years. During each year, the students should develop complete projects working as teams and obtain final products. In this way, it was possible to develop competences that can be interesting for companies and also to increment students’ motivation.
Approaching the Practice Quality Improvement Project in Interventional Radiology.
Reis, Stephen P; White, Benjamin; Sutphin, Patrick D; Pillai, Anil K; Kalva, Sanjeeva P; Toomay, Seth M
2015-12-01
An important component of maintenance of certification and quality improvement in radiology is the practice quality improvement (PQI) project. In this article, the authors describe several methodologies for initiating and completing PQI projects. Furthermore, the authors illustrate several tools that are vital in compiling, analyzing, and presenting data in an easily understandable and reproducible manner. Last, they describe two PQI projects performed in an interventional radiology division that have successfully improved the quality of care for patients. Using the DMAIC (define, measure, analyze, improve, control) quality improvement framework, interventional radiology throughput has been increased, to lessen mediport wait times from 43 to 8 days, and mediport infection rates have decreased from more than 2% to less than 0.4%. Copyright © 2015 American College of Radiology. Published by Elsevier Inc. All rights reserved.
An approach to the relationship, environment-project-administration
International Nuclear Information System (INIS)
Angel Sanin, Enrique
1999-01-01
Interdisciplinary groups working in environmental management, have to deal with three different problems, understanding the regional environment in which the project will be implemented, estimating the environmental impacts and devising the environmental management plan (EMP). These three realities environment, project and management are loosely defined, their limits are not clear and, therefore, several things are mean by the same word. In this article, an attempt to express these three realities in a language with some mathematical rigor is presented, looking for precision in their meaning. Some pertinent conclusions regarding environmental management are derived from the mathematical attempt
The Single And Multi Project Approach To Planning And Scheduling
DEFF Research Database (Denmark)
Andersson, Niclas
2008-01-01
The fragmentation of the construction industry in Denmark is reflected in the organisation of construction projects, which typically involves a large number of subcontractors. The main contractor, being responsible for the planning and scheduling of construction work, is thus faced with the chall......The fragmentation of the construction industry in Denmark is reflected in the organisation of construction projects, which typically involves a large number of subcontractors. The main contractor, being responsible for the planning and scheduling of construction work, is thus faced...
Learning Approaches - Final Report Sub-Project 4
DEFF Research Database (Denmark)
Dirckinck-Holmfeld, Lone; Rodríguez Illera, José Luis; Escofet, Anna
2007-01-01
The overall aim of Subproject 4 is to apply learning approaches that are appropriate and applicable using ICT. The task is made up of two components 4.1 dealing with learning approaches (see deliverable 4.1), and component 4.2 application of ICT (see deliverable 4.2, deliverable 4.3 & deliverable...
Lombardo, Giuseppe M.; Portalone, Gustavo; Colapietro, Marcello; Rescifina, Antonio; Punzo, Francesco
2011-05-01
The ability of caffeic acid to act as antioxidant against hyperoxo-radicals as well as its recently found therapeutic properties in the treatment of hepatocarcinoma, still make this compound, more than 20 years later the refinement of its crystal structure, object of study. It belongs to the vast family of humic substances, which play a key role in the biodegradation processes and easily form complexes with ions widely diffused in the environment. This class of compounds is therefore interesting for potential environmental chemistry applications concerning the possible complexation of heavy metals. Our study focused on the characterization of caffeic acid as a starting necessary step, which will be followed in the future by the application of our findings on the study of the properties of caffeate anion interaction with heavy metal ions. To reach this goal, we applied a low cost approach - in terms of computational time and resources - aimed at the achievement of a high resolution, robust and trustable structure using the X-ray single crystal data, recollected with a higher resolution, as touchstone for a detailed check. A comparison between the calculations carried out with density functional theory (DFT), Hartree-Fock (HF) method and post SCF second order Møller-Plesset perturbation method (MP2), at the 6-31G ** level of the theory, molecular mechanics (MM) and molecular dynamics (MD) was performed. As a consequence we explained on one hand the possible reasons for the pitfalls of the DFT approach and on the other the benefits of using a good and robust force field developed for condensed phases, as AMBER, with MM and MD. The reliability of the latter, highlighted by the overall agreement extended up to the anisotropic displacement parameters calculated by means of MD and the ones gathered by X-ray measurements, makes it very promising for the above-mentioned goals.
Schwieger, Dana; Surendran, Ken
2015-01-01
The value of experiential learning projects (which are usually major assessments in courses) in education has been touted since the early 1900s (Dewey, 1938). These projects have the potential to deepen students' understanding of course topics by allowing them to put concepts into practice and watch the results develop. However, experiential…
International Nuclear Information System (INIS)
Pironkov, L.
2010-01-01
Project specifics: Replacement of analogue process control system with Ovation®based Distributed Control System; Hybrid solution with simulated I&C logic and stimulated Human Machine Interface; Initial design ‐“turn‐key” project based on standard relationship “single customer –single contractor
The Company Approach to Software Engineering Project Courses
Broman, D.; Sandahl, K.; Abu Baker, M.
2012-01-01
Teaching larger software engineering project courses at the end of a computing curriculum is a way for students to learn some aspects of real-world jobs in industry. Such courses, often referred to as capstone courses, are effective for learning how to apply the skills they have acquired in, for example, design, test, and configuration management.…
A systems engineering approach for realizing sustainability in infrastructure projects
Directory of Open Access Journals (Sweden)
Mohamed Matar
2017-08-01
The developed model addresses an identified gap within the current body of knowledge by considering infrastructure projects. Through the ability to simulate different scenarios, the model enables identifying which activities, products, and processes impact the environment more, and hence potential areas for optimization and improvement.
A Coordinated Decentralized Approach to Online Project Development
Mykota, David
2013-01-01
With the growth rate of online learning outpacing traditional face-to-face instruction, universities are beginning to recognize the importance of strategic planning in its development. Making the case for online learning requires sound project management practices and an understanding of the business models on which it is predicated. The objective…
AN APPROACH TO THE QUALITY IMPROVEMENT OF A MASSIVE INVESTMENT PROJECT BY INTEGRATING ICT AND QMS
Directory of Open Access Journals (Sweden)
Tamara Gvozdenovic
2007-12-01
Full Text Available This work has presented an approach to the quality improvement of an investment project by the change in the concept of project management. Building time of the investment project is a complex factor which needs a special attention. It is well known that the PERT method has been applied with long-lasting investment projects, where a big time distance brings about significant uncertainty of future situations. Microsoft Project 2002 and Matlab: Neural Network Toolbox are the software tools used for solving the problem of investment project management.
The DIMBI project – innovative approaches for teaching business informatics
Directory of Open Access Journals (Sweden)
Ivan Kuyumdzhiev
2016-11-01
Full Text Available The purpose of this article is to collect and analyze data on existing methods of teaching business informatics in leading Bulgarian universities and suggest areas for improvements. Based on a collected data guidelines for innovative teaching methods in the field of BI and DW are developed. Proposed methods are divided in several sections – lectures, exercises (groups’ size, tools used, software, hardware, teaching methods, and real life customers, students’ projects, control methods. The findings of conducted feasibility study show that the business, students and universities need an innovative methodology of teaching business informatics and properly implemented this methodology has a high probability of success. This paper is written within the Erasmus plus KA2 project “Developing the innovative methodology of teaching business informatics” (DIMBI, 2015-1-PL01-KA203-0016636.
An approach to knowledge management for EUROSAFE projects
International Nuclear Information System (INIS)
Goldschmidt, F.; Gelder, P. De; Beraha, D.
2005-01-01
The objective of a knowledge management system (KMS) in the field of Nuclear Safety Assessment is to keep competence in expertise and research at the best level. This contribution proposes a diagram of KM organization associated with the Eurosafe Safety Assessment Guide project proposal. The aim of the KM action is to test and bring forward a generic and perennial method of knowledge management adapted to the safety culture. It will be interested to support the access to information useful for the practices of expertise by organizing a knowledge mapping, supporting the exchanges of know-how by the consolidation of a competence network and the externalization of expert knowledge. This article presents the actions in progress at AVN, GRS and IRSN, and suggests some principles based on experience feedbacks drawn from the literature. It is not supposed to be exhaustive but rather to encourage other Technical Support Organizations to take part in this KM action associated with the technical project. We suggest to organize the KM action in three phases: (1) definition of a KM Strategy adapted to the technical project; (2) implementation of KM selected actions (actors sensitization, tests of KM methods, etc); (3) choice and fulfillment of effective and perennial KM solutions. (authors)
Needs assessment in health research projects: a new approach to project management in iran.
Peykari, Niloofar; Owlia, Parviz; Malekafzali, Hossein; Ghanei, Mostafa; Babamahmoodi, Abdolreza; Djalalinia, Shirin
2013-01-01
The science and technology health plan has defined the outline of health research to the national vision of Iran by 2025. The aim of this study was to focus on the process of needs assessment of health research projects also health research priority setting in Iran. THE PROJECT MANAGEMENT LIFE CYCLE HAS FOUR PHASES: Initiation, Planning, Execution and Closure. Based on abovementioned points we conducted the study. Focusing on the needs assessment led to systematic implementation of needs assessment of health project in all of the medical sciences universities. Parallel with this achieved strategies health research priority setting was followed through specific process from empowerment to implementation. We should adopt with more systematic progressive methods of health project managements for both our national convenience as well as our international health research programs.
Varandas, António J. C.
2018-04-01
Because the one-electron basis set limit is difficult to reach in correlated post-Hartree-Fock ab initio calculations, the low-cost route of using methods that extrapolate to the estimated basis set limit attracts immediate interest. The situation is somewhat more satisfactory at the Hartree-Fock level because numerical calculation of the energy is often affordable at nearly converged basis set levels. Still, extrapolation schemes for the Hartree-Fock energy are addressed here, although the focus is on the more slowly convergent and computationally demanding correlation energy. Because they are frequently based on the gold-standard coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)], correlated calculations are often affordable only with the smallest basis sets, and hence single-level extrapolations from one raw energy could attain maximum usefulness. This possibility is examined. Whenever possible, this review uses raw data from second-order Møller-Plesset perturbation theory, as well as CCSD, CCSD(T), and multireference configuration interaction methods. Inescapably, the emphasis is on work done by the author's research group. Certain issues in need of further research or review are pinpointed.
Nuclear pairing reduction due to rotation and blocking
International Nuclear Information System (INIS)
Wu, X.; Zhang, Z. H.; Zeng, J. Y.; Lei, Y. A.
2011-01-01
Nuclear pairing gaps of normally deformed and superdeformed nuclei are investigated using the particle-number-conserving (PNC) formalism for the cranked shell model, in which the blocking effects are treated exactly. Both rotational frequency ω dependence and seniority (number of unpaired particles) ν dependence of the pairing gap Δ-tilde are investigated. For the ground-state bands of even-even nuclei, PNC calculations show that, in general, Δ-tilde decreases with increasing ω, but the ω dependence is much weaker than that calculated by the number-projected Hartree-Fock-Bogolyubov approach. For the multiquasiparticle bands (seniority ν>2), the pairing gaps stay almost ω independent. As a function of the seniority ν, the bandhead pairing gaps Δ-tilde(ν,ω=0) decrease slowly with increasing ν. Even for the highest seniority ν bands identified so far, Δ-tilde(ν,ω=0) remains greater than 70% of Δ-tilde(ν=0,ω=0).
A Constrained and Guided Approach for Managing Software Engineering Course Projects
Cheng, Y.-P.; Lin, J. M.-C.
2010-01-01
This paper documents several years of experimentation with a new approach to organizing and managing projects in a software engineering course. The initial failure and subsequent refinements that the new approach has been through since 2004 are described herein. The "constrained and guided" approach, as it is called, has helped to reduce…
Open Learning Approach with Remote Experiments: OLAREX Project
Directory of Open Access Journals (Sweden)
Javier Garcia-Zubia
2013-10-01
Full Text Available The project’s primary target groups are the European secondary schools. More specifically: secondary school and university teachers, students and managers of schools, museum employees and their visitors, and other STEM education providers. The main goal of the OLAREX project is to offer the providers of formal and non-formal education an efficient way to improve their e-didactic and digital competences. For this purpose a training program is created with using ICT-based learning materials, remote laboratories, and e-learning methodologies
Individual Learning in Construction Projects: Professions and their Approaches
Directory of Open Access Journals (Sweden)
Ingeborg Wasif
2010-10-01
Full Text Available New materials, use of sophisticated technologies and increased customer demands, in combination with growing competition among construction companies, have led to a high organizational boundaries. The results indicate that personal networks are the most common source of learning for all professions. While clients, architects, and designers also engage in reading and attending courses, site managers and workers are less engaged in these activities. Experimenting and organizing for learning appear to be underutilized strategies by all professions. This leads to the conclusion that attempts to increase learning have to address the differences in learning behaviours of the various groups. Further, focus on experimenting and organizing for learning is a possibility to change the learning behaviour from learning as a consequence of problems to learning for future improvement.degree of specialization. For successful integration of the different professional specialists, there is a need for shared learning between project co-workers. Based on twenty eight interviews in six different Swedish construction projects, this paper illustrates strategies for individual and shared learning, among different actors and across various
The Hanford Environmental Dose Reconstruction (HEDR) Project: Technical approach
International Nuclear Information System (INIS)
Napier, B.A.; Freshley, M.D.; Gilbert, R.O.; Haerer, H.A.; Morgan, L.G.; Rhoads, R.E.; Woodruff, R.K.
1990-01-01
Historical measurements and current assessment techniques are being combined to estimate potential radiation doses to people from radioactive releases to the air, the Columbia River, soils, and ground water at the Hanford Site since 1944. Environmental contamination from these releases has been monitored, at varying levels of detail, for 45 yr. Phase I of the Hanford Environmental Reconstruction Project will estimate the magnitude of potential doses, their areal extends, and their associated uncertainties. The Phase I study area comprises 10 counties in eastern Washington and northern Oregon, within a 100-mi radius of the site, including a stretch of the Columbia River that was most significantly affected. These counties contain a range of projected and measured contaminant levels, environmental exposure pathways, and population groups. Phase I dose estimates are being developed for the periods 1944 through 1947 for air pathways and 1964 through 1966 for river pathways. Important radionuclide/pathway combinations include fission products, such as 131 I, in milk for early atmospheric releases and activation products, such as 32 P and 65 Zn, in fish for releases to the river. Potential doses range over several orders of magnitude within the study area. We will expand the time periods and study are in three successive phases, as warranted by results of Phase I
International Nuclear Information System (INIS)
Carpenter, C.P.; Marks, M.L.; Smiley, S.L.; Gallaher, D.M.; Williams, K.D.
2006-01-01
The U.S. Department of Energy (DOE) used a project management approach to transition the Miamisburg Closure Project from cleanup by the Office of Environmental Management (EM) to post-closure operations by the Office of Legacy Management (LM). Two primary DOE orders were used to guide the site transition: DOE Order 430.1B, Real Property Asset Management, for assessment and disposition of real property assets and DOE Order 413.3, Program and Project Management for Acquisition of Capital Assets, for project closeout of environmental cleanup activities and project transition of post-closure activities. To effectively manage these multiple policy requirements, DOE chose to manage the Miamisburg Closure Project as a project under a cross-member transitional team using representatives from four principal organizations: DOE-LM, the LM contractor S.M. Stoller Corporation, DOE-EM, and the EM contractor CH2M Hill Mound Inc. The mission of LM is to manage the Department's post-transition responsibilities and long-term care of legacy liabilities and to ensure the future protection of human health and the environment for cleanup sites after the EM has completed its cleanup activities. (authors)
Financing offshore projects: The banker's approach to risk
International Nuclear Information System (INIS)
Beldam, R.A.
1994-01-01
The author has attempted to consider why companies chose to share risks with banks and looked in particular at the unique risk sharing aspect of project financing and how this may be reflected in the loan documentation. He also has considered the current market place and examined some trends for the future. The future challenge in the North Sea is going to be to use existing and new technology to reduce capital and operating costs, balanced with optimal recovery and safety. From a bank perspective, this type of work is extremely satisfying, if challenging, and the author has no doubt banks will continue to play their part in the future of offshore development wherever it occurs around the world
Energy consumption projection of Nepal: An econometric approach
DEFF Research Database (Denmark)
Parajuli, Ranjan; Østergaard, Poul A.; Dalgaard, Tommy
2014-01-01
In energy dependent economies, energy consumption is often linked with the growth in Gross Domestic Product (GDP). Energy intensity, defined herewith, as the ratio of the total primary energy consumption (TPE) to the GDP, is a useful concept for understanding the relation between energy demand...... and economic development. The scope of this article is to assess the future primary energy consumption of Nepal, and the projection is carried out along with the formulation of simple linear logarithmic energy consumption models. This initiates with a hypothesis that energy consumption is dependent...... with the national macro-economic parameters. To test the hypothesis, nexus between energy consumption and possible determinant variables are examined. Status of energy consumption between the period of 1996 and 2009, and for the same period, growth of economic parameters are assessed. Three scenarios are developed...
The snake geothermal drilling project. Innovative approaches to geothermal exploration
Energy Technology Data Exchange (ETDEWEB)
Shervais, John W. [Utah State Univ., Logan, UT (United States); Evans, James P. [Utah State Univ., Logan, UT (United States); Liberty, Lee M. [Boise State Univ., ID (United States); Schmitt, Douglas R. [University of Alberta, Canada; Blackwell, David D. [Southern Methodist Univ., Dallas, TX (United States)
2014-02-21
The goal of our project was to test innovative technologies using existing and new data, and to ground-truth these technologies using slim-hole core technology. The slim-hole core allowed us to understand subsurface stratigraphy and alteration in detail, and to correlate lithologies observed in core with surface based geophysical studies. Compiled data included geologic maps, volcanic vent distribution, structural maps, existing well logs and temperature gradient logs, groundwater temperatures, and geophysical surveys (resistivity, magnetics, gravity). New data included high-resolution gravity and magnetic surveys, high-resolution seismic surveys, three slimhole test wells, borehole wireline logs, lithology logs, water chemistry, alteration mineralogy, fracture distribution, and new thermal gradient measurements.
INEL Waste and Environmental Information Integration Project approach and concepts
International Nuclear Information System (INIS)
Dean, L.A.; Fairbourn, P.J.; Randall, V.C.; Riedesel, A.M.
1994-06-01
The Idaho National Engineering, Laboratory (INEL) Waste and Environmental Information integration Project (IWEIIP) was established in December 1993 to address issues related to INEL waste and environmental information including: Data quality; Data redundancy; Data accessibility; Data integration. This effort includes existing information, new development, and acquisition activities. Existing information may not be a database record; it may be an entire document (electronic, scanned, or hard-copy), a video clip, or a file cabinet of information. The IWEIIP will implement an effective integrated information framework to manage INEL waste and environmental information as an asset. This will improve data quality, resolve data redundancy, and increase data accessibility; therefore, providing more effective utilization of the dollars spent on waste and environmental information
A project management approach to an ACPE accreditation self-study.
Dominelli, Angela; Iwanowicz, Susan L; Bailie, George R; Clarke, David W; McGraw, Patrick S
2007-04-15
In preparation for an on-site evaluation and accreditation by the American Council on Pharmaceutical Education (ACPE), the Albany College of Pharmacy employed project management techniques to complete a comprehensive self-study. A project lifecycle approach, including planning, production, and turnover phases, was used by the project's Self-Study Steering Committee. This approach, with minimal disruption to college operations, resulted in the completion of the self-study process on schedule. Throughout the project, the Steering Committee maintained a log of functions that either were executed successfully or in hindsight, could have been improved. To assess the effectiveness of the project management approach to the the self-study process, feedback was obtained from the College community through a poststudy survey. This feedback, coupled with the Steering Committee's data on possible improvements, form the basis for the lessons learned during this self-study process.
Selection and approbation of new technical approaches in innovation projects
International Nuclear Information System (INIS)
Matvienko, V.A.; Pastushenko, V.N.; Zvorykin, K.O.; Zvorykin, L.O.
1999-01-01
Large-scale technical approaches based on the application of new technologies, equipment, tools and other production equipping means (PEM) are to be previously tested by technical and engineering practice and thoroughly approved. These circumstances create objective prerequisites for organization within the infrastructure of the 'OU' of a special sector to solve such a problem. A structure-and-logic model of the infrastructure sector is represented. Principal trends of activities of the proposed new sector of the 'OU' infrastructure may become the following ones: personnel training, skill rising and attestation; adaptation of new samples of universal and auxiliary equipment; new technologies and equipment approbation; approbation of actions in nonstandard situations
Uranium Mill Tailings Remedial Action Project: technical approach document
International Nuclear Information System (INIS)
1986-05-01
The Uranium Mill Tailings Radiation Control Act of 1978, PL95-604, grants the Secretary of Energy authority and responsibility to perform such actions as are necessary to minimize radiation health hazards and other environmental hazards from inactive uranium mill sites. These cleanup actions are to be performed in compliance with the EPA standards (40 CFR Part 192) which became final on March 7, 1983. This document describes the general technical approaches and design criteria that are adopted by the US Department of Energy (DOE) in order to implement Remedial Action Plans (RAPs) and final designs that comply with EPA standards
Baarveld, Marlijn; Smit, Marnix; Dewulf, Geert P.M.R.
2015-01-01
Dealing with conflict through dialogue receives considerable attention in current planning approaches. However, debate and negotiation are also inevitable features in the planning of urban redevelopment projects. Insight into the negotiation process contributes to current planning practice as
A "one health" approach to address emerging zoonoses: the HALI project in Tanzania.
Jonna A K Mazet; Deana L Clifford; Peter B Coppolillo; Anil B Deolalikar; Jon D Erickson; Rudovick R Kazwala
2009-01-01
Jonna Mazet and colleagues describe their work in the Tanzania-based HALI Project, which adopts the ?One Health? approach to address emerging zoonoses and that recognizes the interconnectedness of human, animal, and environmental health.
EPA and the Louisville Metro Air Pollution Control District (LMAPCD) are working together on a research project to demonstrate NGEM approaches near facilities in the Rubbertown industrial area of Louisville, KY.
ALARA approach on Qinshan unit I lower internals recovery project
International Nuclear Information System (INIS)
Wu Meijing; Xu Hongming; Jiang Jianqi; Chen Zhongyu
2000-01-01
Qinshan unit-1 is a 300 Mwe prototype PWR. It has been successfully operating for 4 fuel cycles about 10 years. Some loose parts by the failure of the guide tube of the reactor core neutron flux measurement thimble were observed on the lower structure of Core Barrel during periodical inspection after unloading all fuel assemblies. Qinshan Nuclear Power Company selected Westinghouse Electric Company as contractor to perform the reactor core barrel recovery service after negotiated with 4 world big company. QNPC and Westinghouse worked together to approach the ALARA by increasing water shielding, adding additional steel shielding, fuel pool cleaning and using the long hand tools, remote camera system. The training, mock-up exercise, good personal behavior was greatly contributed to the ALARA approaching. The collective dose and personal exposure of this job were successful controlled by implementing the preset ALARA program. The job was done by the cost of 70 man.mSv collective dose and 3.5 mSv maximum personal exposure despite of the high dose-rate which hot spot in some place is up to several hundred Sv per hour. (author)
Towards a project-based service delivery approach : Uncovering organisational tensions
12330841 - Van der Waldt, Gerrit
2009-01-01
In line with the modernizing, re-inventing and alternative service delivery paradigm, governments increasingly utilise project-based methodologies to improve service delivery. There is general agreement that projects are becoming increasingly important for government institutions to operationalise strategic objectives and policy programmes. This approach is commonly known as ‗Management-by-Projects‘. To adopt this approach requires of public institutions to adjust their existing structures...
Loeber, A.; Vermeulen, T.; Barbier, M.; Elzen, B.
2012-01-01
The management of projects for sustainable innovation is characterised by a variety of intricacies. Facilitators play a central role in dealing with these challenges. Adopting an empirical approach, this chapter discusses the practical approaches and attitudes that facilitators develop to deal with such challenges in the domain of agricultural innovation. To that end, the paper presents a list of four intricacies inherent in running projects that seek to enhance sustainable development, based...
Rodrigues Jr., Jose Florencio; Lehmann, Angela Valeria Levay; Fleith, Denise De Souza
2005-01-01
Building on previous studies centred on the interaction between adviser and advisee in masters thesis projects, in which a qualitative approach was used, the present study uses factor analysis to identify the factors that determine either a successful or unsuccessful outcome for the masters thesis project. There were five factors relating to the…
Optimal control of quantum systems: a projection approach
International Nuclear Information System (INIS)
Cheng, C.-J.; Hwang, C.-C.; Liao, T.-L.; Chou, G.-L.
2005-01-01
This paper considers the optimal control of quantum systems. The controlled quantum systems are described by the probability-density-matrix-based Liouville-von Neumann equation. Using projection operators, the states of the quantum system are decomposed into two sub-spaces, namely the 'main state' space and the 'remaining state' space. Since the control energy is limited, a solution for optimizing the external control force is proposed in which the main state is brought to the desired main state at a certain target time, while the population of the remaining state is simultaneously suppressed in order to diminish its effects on the final population of the main state. The optimization problem is formulated by maximizing a general cost functional of states and control force. An efficient algorithm is developed to solve the optimization problem. Finally, using the hydrogen fluoride (HF) molecular population transfer problem as an illustrative example, the effectiveness of the proposed scheme for a quantum system initially in a mixed state or in a pure state is investigated through numerical simulations
Directory of Open Access Journals (Sweden)
Raj Kumar Chopra
2016-09-01
Full Text Available Non functional requirements must be selected for implementation together with functional requirements to enhance the success of software projects. Three approaches exist for performing the prioritization of non functional requirements using the suitable prioritization technique. This paper performs experimentation on three different complexity versions of the industrial software project using cost-value prioritization technique employing three approaches. Experimentation is conducted to analyze the accuracy of individual approaches and the variation of accuracy with the complexity of the software project. The results indicate that selecting non functional requirements separately, but in accordance with functionality has higher accuracy amongst the other two approaches. Further, likewise other approaches, it witnesses the decrease in accuracy with increase in software complexity but the decrease is minimal.
A new approach for modelling variability in residential construction projects
Directory of Open Access Journals (Sweden)
Mehrdad Arashpour
2013-06-01
Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers.
A new approach for modelling variability in residential construction projects
Directory of Open Access Journals (Sweden)
Mehrdad Arashpour
2013-06-01
Full Text Available The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers.
International Nuclear Information System (INIS)
Hopkins, A.; Stewart, C.; Cabble, K.
1994-01-01
The primary purpose of Project Chariot was to investigate the technical problems and assess the effect of the proposed harbor excavation using nuclear explosives in Alaska. However, no nuclear devices were brought to the Project Chariot site. Between 1959 and 1961 various environmental tests were conducted. During the course of these environmental studies, the U.S. Geological Survey (USGS) granted the use of up to 5 curies of radioactive material at the Chariot site in Cape Thompson, Alaska; however only 26 millicuries were ever actually used. The tests were conducted in 12 test plots which were later gathered together and were mixed with in situ-soils generating approximately 1,600 cubic feet of soil. This area was then covered with four feet of clean soil, creating a mound. In 1962, the site was abandoned. A researcher at the University of Alaska at Fairbanks obtained in formation regarding the tests conducted and the materials left at the Project Chariot site. In response to concerns raised through the publication of this information, it was decided by the Department of Energy (DOE) that total remediation of the mound be completed within the year. During the summer of 1993, IT Corporation carried out the assessment and remediation of the Project Chariot site using a streamlined approach to waste site decision making called the Observational Approach (OA), and added elements of the new DOE Streamlined Approach for Environmental Restoration (SAFER). This remediation and remediation approach is described
Relational approach in managing construction project safety: a social capital perspective.
Koh, Tas Yong; Rowlinson, Steve
2012-09-01
Existing initiatives in the management of construction project safety are largely based on normative compliance and error prevention, a risk management approach. Although advantageous, these approaches are not wholly successful in further lowering accident rates. A major limitation lies with the approaches' lack of emphasis on the social and team processes inherent in construction project settings. We advance the enquiry by invoking the concept of social capital and project organisational processes, and their impacts on project safety performance. Because social capital is a primordial concept and affects project participants' interactions, its impact on project safety performance is hypothesised to be indirect, i.e. the impact of social capital on safety performance is mediated by organisational processes in adaptation and cooperation. A questionnaire survey was conducted within Hong Kong construction industry to test the hypotheses. 376 usable responses were received and used for analyses. The results reveal that, while the structural dimension is not significant, the mediational thesis is generally supported with the cognitive and relational dimensions affecting project participants' adaptation and cooperation, and the latter two processes affect safety performance. However, the cognitive dimension also directly affects safety performance. The implications of these results for project safety management are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.
Cost effective solutions for field development. System supplier approach to projects and operations
International Nuclear Information System (INIS)
Moe, P.O.
1994-01-01
The conference paper outlines the most important elements for a new approach to project realisation that enable a cost reduction of 30-50% compared to conventional methods. The achievements are based on studies and evaluations to the Norwegian Vigdis development project. The system elements covered are the electrical and automation systems including safety and process control and all traditional phases of a project from concept design to the operational phase. The concept involves new principles for project execution where traditional borderlines and interfaces between the various participants have been redefined. Management attention has been verified as an important prerequisite for a successful implementation of this strategy. 2 figs
International Nuclear Information System (INIS)
Kelly, J.W.
1994-06-01
This presentation describes a team approach, at the totalproject level that focused team members with common objectives, for the transition to start-up and operation of the project. The Integrated Management Team (IMT) approach has been successful for this US Department of Energy (DOE) environmental restoration project at the Hanford Site in Richland, Washington. The $53.8-million project will collect, treat, and dispose of low-level mixed waste water discharges from the Hanford Site. Construction is scheduled for completion in September 1994 and facility start-up in June 1995. The project challenge is for leadership that is committed to the transition from construction to operation of the environmental restoration project
Smart energy households' pilot projects in the Netherlands with a design-driven approach
Geelen, D.V.; Scheepens, A.; Kobus, C.; Obinna, U.; Mugge, R.; Schoormans, J.; Reinders, Angelina H.M.E.
2013-01-01
Residential smart grid projects can be evaluated by a design-driven approach, which focuses on gaining insights for successful product and service development by taking the end-users as a starting point. Because only little experience exists with this design-driven approach, this paper addresses how
The paradigm of consumer-driven and responsive supply chains: An integrated project approach
Zimmermann, K.L.; Lans, van der I.A.
2009-01-01
This paper describes an integrated project approach that forms the basis of the studies on consumer-driven innovative and responsive supply chains in ISAFRUIT Pillar 1. This integrated approach leads to a wide range of indepth results on trends, preferences, and innovativeness of the European
Loeber, A.; Vermeulen, T.; Barbier, M.; Elzen, B.
2012-01-01
The management of projects for sustainable innovation is characterised by a variety of intricacies. Facilitators play a central role in dealing with these challenges. Adopting an empirical approach, this chapter discusses the practical approaches and attitudes that facilitators develop to deal with
DEFF Research Database (Denmark)
Grex, Sara
2004-01-01
This paper asks how project-based organizations can be developed in order to establish and sustain innovation. The question is being explored by examining and comparing two approaches to organizational change. One approach emphasizes planning, regulation and control and creation of changes through...
Generic project definitions for improvement of health care delivery: a case-based approach.
Niemeijer, Gerard C; Does, Ronald J M M; de Mast, Jeroen; Trip, Albert; van den Heuvel, Jaap
2011-01-01
The purpose of this article is to create actionable knowledge, making the definition of process improvement projects in health care delivery more effective. This study is a retrospective analysis of process improvement projects in hospitals, facilitating a case-based reasoning approach to project definition. Data sources were project documentation and hospital-performance statistics of 271 Lean Six Sigma health care projects from 2002 to 2009 of general, teaching, and academic hospitals in the Netherlands and Belgium. Objectives and operational definitions of improvement projects in the sample, analyzed and structured in a uniform format and terminology. Extraction of reusable elements of earlier project definitions, presented in the form of 9 templates called generic project definitions. These templates function as exemplars for future process improvement projects, making the selection, definition, and operationalization of similar projects more efficient. Each template includes an explicated rationale, an operationalization in the form of metrics, and a prototypical example. Thus, a process of incremental and sustained learning based on case-based reasoning is facilitated. The quality of project definitions is a crucial success factor in pursuits to improve health care delivery. We offer 9 tried and tested improvement themes related to patient safety, patient satisfaction, and business-economic performance of hospitals.
Directory of Open Access Journals (Sweden)
Aidin Delgoshaei
2016-09-01
Full Text Available Purpose: The issue resource over-allocating is a big concern for project engineers in the process of scheduling project activities. Resource over-allocating drawback is frequently seen after scheduling of a project in practice which causes a schedule to be useless. Modifying an over-allocated schedule is very complicated and needs a lot of efforts and time. In this paper, a new and fast tracking method is proposed to schedule large scale projects which can help project engineers to schedule the project rapidly and with more confidence. Design/methodology/approach: In this article, a forward approach for maximizing net present value (NPV in multi-mode resource constrained project scheduling problem while assuming discounted positive cash flows (MRCPSP-DCF is proposed. The progress payment method is used and all resources are considered as pre-emptible. The proposed approach maximizes NPV using unscheduled resources through resource calendar in forward mode. For this purpose, a Genetic Algorithm is applied to solve. Findings: The findings show that the proposed method is an effective way to maximize NPV in MRCPSP-DCF problems while activity splitting is allowed. The proposed algorithm is very fast and can schedule experimental cases with 1000 variables and 100 resources in few seconds. The results are then compared with branch and bound method and simulated annealing algorithm and it is found the proposed genetic algorithm can provide results with better quality. Then algorithm is then applied for scheduling a hospital in practice. Originality/value: The method can be used alone or as a macro in Microsoft Office Project® Software to schedule MRCPSP-DCF problems or to modify resource over-allocated activities after scheduling a project. This can help project engineers to schedule project activities rapidly with more accuracy in practice.
The technique of project activity: A new approach in Russian preschool.
Directory of Open Access Journals (Sweden)
Veraksa N.E.
2015-06-01
Full Text Available Project activity has a long history of implementation in education (Kilpatrick, 1918. This article describes the approach to project activity that became widespread in preschool education in Russia in the late 1990s. This approach is based on the cultural-historical theory of Vygotsky (1978, Venger’s (1988 understanding of intellectual giftedness, as well as an understanding of project activity proposed by Leontiev (2000. At the heart of project activity lies children’s exploration of the space of possibilities — that is, their search for action options that correspond to their personal motives and express their individuality. The main features of project activity are the problem situation to be presented to the child; the subjectivity of all its participants, including teachers; and its nature, which includes its social context. Three main types of project activity are presented: research, creative, and normative; each has its own structure and value for children’s development. Examples of their implementation in preschool settings are provided. The impact of project activity on all its participants in preschool — children, teachers, parents — is addressed. The article shows the effectiveness of project activity for educational work with both intellectually gifted and normally developing children.
Regulation Of Hydraulic Fracturing In South Africa: A Project Life-Cycle Approach?
Directory of Open Access Journals (Sweden)
Willemien du Plessis
2015-12-01
Full Text Available This note deals with the 2015 regulations pertaining to hydraulic fracturing in South Africa from a project life-cycle approach. A brief history of the fragmentation of the regulation of environmental and mining related matters is provided, followed by a discussion of the application of the 2015 regulations during the project life cycle, ie the pre-commencement phase, the design and authorisation phase, the testing phase, the operational phase and the decommissioning and closure phase.
Sylvain Lenfle
2011-01-01
International audience; This paper discusses the literature on the management of projects with unforeseeable uncertainty. Recent work demonstrates that, when confronted with unforeseeable uncertainties, managers can adopt either a learning, trial-and-error-based strategy, or a parallel approach. In the latter, different solutions are developed in parallel and the best one is chosen when enough information becomes available. Studying the case of the Manhattan Project, which historically exempl...
Exploring Community-Oriented Approaches in Demand Side Management Projects in Europe
Directory of Open Access Journals (Sweden)
Anna Mengolini
2016-12-01
Full Text Available This paper seeks to investigate if the theoretical and political trends towards a more collective dimension of energy use are reflected in the design and development of demand side management (DSM pilot projects in Europe. Specifically, the paper analyses DSM projects in the database of the Joint Research Centre (JRC of the European Commission to capture signs of a new attention towards the wider context in which consumers live and towards the social dimension associated with energy consumption. To this end, the paper investigates the projects’ scope (in terms of project’s partners, end-use sectors and targeted services as well as the consumer engagement strategies that projects use. These elements reflect the projects’ consideration for the socio-economic dimension of the community where the pilots take place and their inclination to build on community dynamics. The analysis shows that DSM projects in the EU are increasingly being designed and developed with a collegial approach to energy consumption in mind, although an integrated approach is still missing. In addition, research is still needed to link the use of this innovative approach to project results. A closer look at the developments and results of these projects can help to identify what works and what doesn’t in real life experiences, thus supporting effective policy making at the EU and national level.
USING OF THE PROJECT-ORIENTED APPROACH IN THE INNOVATIVE ACTIVITY MANAGEMENT
Directory of Open Access Journals (Sweden)
Варвара Михайлівна ПІТЕРСЬКА
2016-02-01
Full Text Available The article describes the current state of science in Ukraine, indicated the main directions of research funding. The methodological approach of working out of the project-oriented strategy of innovative development of scientific activity, including the implementation of international trends and support of research is proposed. Using of a project-oriented approach of research activities due to the need of reducing of the research cycle and strengthen expenditure control capabilities due to restrictions of funding research projects from the state. It should be noted that the structuring of research, given the project approach, allows engaging of the implementation of the research project professionals with good knowledge and skills and create a team activity focused on quality results. Innovations aren‘t still properly means the improvement of competitiveness in Ukraine. Thus, the problem of transition to an innovative development model retains its relevance, that significantly enhanced in the light of current external and internal trends. Using of the project-oriented innovation management due to the need to shorten the cycle of research and to strengthen the control over the expenditure of funds in connection with the limited funding of scientific research by the state.
Directory of Open Access Journals (Sweden)
Tinggui Chen
2013-01-01
Full Text Available Complex engineering system optimization usually involves multiple projects or tasks. On the one hand, dependency modeling among projects or tasks highlights structures in systems and their environments which can help to understand the implications of connectivity on different aspects of system performance and also assist in designing, optimizing, and maintaining complex systems. On the other hand, multiple projects or tasks are either happening at the same time or scheduled into a sequence in order to use common resources. In this paper, we propose a dynamic intelligent decision approach to dependency modeling of project tasks in complex engineering system optimization. The approach takes this decision process as a two-stage decision-making problem. In the first stage, a task clustering approach based on modularization is proposed so as to find out a suitable decomposition scheme for a large-scale project. In the second stage, according to the decomposition result, a discrete artificial bee colony (ABC algorithm inspired by the intelligent foraging behavior of honeybees is developed for the resource constrained multiproject scheduling problem. Finally, a certain case from an engineering design of a chemical processing system is utilized to help to understand the proposed approach.
Frey, Thorsten
2014-01-01
Due to the growing importance of IT-based innovations, contemporary firms face an excessive number of proposals for IT projects. As typically only a fraction of these projects can be implemented with the given capacity, IT project portfolio management as a relatively new discipline has received growing attention in research and practice in recent years.?Thorsten Frey demonstrates how companies are struggling to find the right balance between local autonomy and central overview about all projects in the organization. In this context, impacts of different contextual factors on the design of governance arrangements for IT project portfolio management are demonstrated. Moreover, consequences of the use of different organizational designs are analyzed. The author presents insights from a qualitative empirical study as well as a simulative approach.
International Nuclear Information System (INIS)
Feng Cun-Fang; Wang Ying-Hai
2011-01-01
Projective synchronization in modulated time-delayed systems is studied by applying an active control method. Based on the Lyapunov asymptotical stability theorem, the controller and sufficient condition for projective synchronization are calculated analytically. We give a general method with which we can achieve projective synchronization in modulated time-delayed chaotic systems. This method allows us to adjust the desired scaling factor arbitrarily. The effectiveness of our method is confirmed by using the famous delay-differential equations related to optical bistable or hybrid optical bistable devices. Numerical simulations fully support the analytical approach. (general)
Designing “Theory of Machines and Mechanisms” course on Project Based Learning approach
DEFF Research Database (Denmark)
Shinde, Vikas
2013-01-01
by the industry and the learning outcomes specified by the National Board of Accreditation (NBA), India; this course is restructured on Project Based Learning approach. A mini project is designed to suit course objectives. An objective of this paper is to discuss the rationale of this course design......Theory of Machines and Mechanisms course is one of the essential courses of Mechanical Engineering undergraduate curriculum practiced at Indian Institute. Previously, this course was taught by traditional instruction based pedagogy. In order to achieve profession specific skills demanded...... and the process followed to design a project which meets diverse objectives....
Coulomb displacement energies in nuclei: a new approach
International Nuclear Information System (INIS)
Auerbach, N.; Tel Aviv Univ.; Bernard, V.; Nguyen, V.G.
1978-04-01
The neutron core polarization gives rise to an important correction to the direct Coulomb contribution when one calculates the Coulomb displacement energies. In the Hartree-Fock model it is shown that this correction is about 2% to 4.5% in medium and heavy nuclei. The core polarization as well as other higher order effects can be included by using a selfconsistent description of the analog state in a complete proton particle-neutron hole space. The Coulomb displacement energies in 48 Ca, 88 Sr and 208 Pb have been calculated using Skyrme interactions SIII and SIV. A good agreement with experiment is obtained
An approximate approach to quantum mechanical study of biomacromolecules
Chen, Xihua
method/basis-set levels of the quantum chemical calculation on the MFCC-downhill simplex optimization are also discussed. Finally, the MFCC-downhill simplex method is tested, as a general multiatomic case study, on a molecular system of cyclo-AAGAGG·H 2O to optimize the binding structure of water molecule to the fixed cyclohexapeptide. The MFCC-downhill simplex optimization results in good agreement with the crystal structure. The MFCC-downhill simplex method should be applicable to optimize the structures of ligands that bind to biomacromolecules such as proteins and DNAs. In Chapter 4, we propose a new approximate method for efficient calculation of biomacromolecular electronic properties, using a Density Matrix (DM) scheme which is integrated with the MFCC approach. In this MFCC-DM method, a biomacro-molecule such as a protein is partitioned by an MFCC scheme into properly capped fragments and concaps whose density matrices are calculated by conventional ab initio methods. These sub-system density matrices are then assembled to construct the full system density matrix which is finally employed to calculate the electronic energy, dipole moment, electronic density, electrostatic potential, etc., of the protein using Hartree-Fock or Density Functional Theory methods. By this MFCC-DM method, the self-consistent field (SCF) procedure for solving the full Hamiltonian problem is circumvented. Two implementations of this approach, MFCC-SDM and MFCC-GDM, are discussed. Systematic numerical studies are carried out on a series of extended polyglycines CH3CO-(GLY) n-NHCH3 (n=3-25) and excellent results are obtained. In Chapter 5, we present an improvement of MFCC-DM method and introduce a pairwise interaction correction (PIC) with which the MFCC-DM method is applicable to study a real-world protein with short-range structural complexity such as hydrogen bonding and close contact. In this MFCC-DM-PIC method, a protein molecule is partitioned into properly capped fragments and
Directory of Open Access Journals (Sweden)
Lu Guangyan
2017-01-01
Full Text Available With the rapid development of science and technology, emerging information technologies have significantly changed the daily life of people. In such context, strategic project selection for high-end equipment manufacturing industries faces more and more complexities and uncertainties with the consideration of several complex criteria. For example, a group of experts rather than a single expert should be invited to select strategic project for high-end equipment manufacturing industries and the experts may feel difficulty to express their preferences towards different strategic projects due to their limited cognitive capabilities. In order to handle these complexities and uncertainties, the criteria framework of strategic project selection is firstly constructed based on the characteristics of high-end equipment manufacturing industries and then evidential reasoning (ER approach is introduced in this paper to help experts express their uncertain preferences and aggregate these preferences to generate an appropriate strategic project. A real case of strategic project selection in a high-speed train manufacturing enterprise is investigated to demonstrate the validity of the ER approach in solving strategic project selection problem.
Planning and urbanistic projects – the non-author approach and issues of synergy in cooperation
Directory of Open Access Journals (Sweden)
Liljana Jankovič Grobelšek
2005-01-01
Full Text Available The article presents the non-author approach to urbanistic and planning projects. The project leader guides the entire project team, yet particular coordinators are also important. Contrary to authorship in architectural projects, in physical planning authorship is often or even always completely shared. Not only because planning projects can change significantly during adoption procedures, but mainly because there are many participating actors (designers, planners, commissioners and/or investors etc. that are involved in any project’s undertaking. Experience proves that the non-author approach is beneficial for good project management and creation of conditions for constructive cooperation within an interdisciplinary working group and with all the other contributing parties. Two tested examples are presented. Their comparison is very interesting, since the first example shows a project where good cooperation between the client, investor and designers, as well as willing interested public, conditioned quality improvements, while the second (because of the public and consequently against its interests diminished its quality significantly. Our judgement is that the quantity of the often mentioned necessity of public involvement is actually sufficient. There are no obstacles for public participation in urbanistic and physical planning, as long as the public is interested. Troubles are often triggered elsewhere – how to safeguard the common, public interest before particular publics (e.g. neighbours, the immediately affected etc..
Directory of Open Access Journals (Sweden)
Олег Богданович ЗАЧКО
2016-03-01
Full Text Available The methods and models of safety-oriented project management of the development of complex systems are proposed resulting from the convergence of existing approaches in project management in contrast to the mechanism of value-oriented management. A cognitive model of safety oriented project management of the development of complex systems is developed, which provides a synergistic effect that is to move the system from the original (pre condition in an optimal one from the viewpoint of life safety - post-project state. The approach of assessment the project complexity is proposed, which consists in taking into account the seasonal component of a time characteristic of life cycles of complex organizational and technical systems with occupancy. This enabled to take into account the seasonal component in simulation models of life cycle of the product operation in complex organizational and technical system, modeling the critical points of operation of systems with occupancy, which forms a new methodology for safety-oriented management of projects, programs and portfolios of projects with the formalization of the elements of complexity.
Energy Technology Data Exchange (ETDEWEB)
Hinshelwood, E; McCallum, D
2001-07-01
The overall aim was to develop and test a range of methods for a Participatory Assessment Process (PAP) in a large community on the subject of a Renewable Energy project in the area. Furthermore, to extract lessons regarding the methods and approaches undertaken. The specific objectives were: 1. To identify and shape appropriate tools, methods and approaches for undertaking a fair community assessment process regarding a Renewable Energy project in the locality. 2. To conduct an in-depth (ten month) community consultation and assessment process for a proposed wind farm. 3. To assess the methods and approaches used in the community consultation and assessment process for their efficiency and value to other developers and community groups. 4. To write up and disseminate the findings regarding the most valuable, efficient and appropriate methods and approaches undertaken. (Author)
COMPARISONS BETWEEN AND COMBINATIONS OF DIFFERENT APPROACHES TO ACCELERATE ENGINEERING PROJECTS
Directory of Open Access Journals (Sweden)
H. Steyn
2012-01-01
Full Text Available
ENGLISH ABSTRACT: In this article, traditional project management methods such as PERT and CPM, as well as fast-tracking and systems approaches, viz. concurrent engineering and critical chain, are reviewed with specific reference to their contribution to reducing the duration of the execution phase of engineering projects. Each of these techniques has some role to play in the acceleration of project execution. Combinations of approaches are evaluated by considering the potential of sets consisting of two different approaches each. While PERT and CPM approaches have been combined for many years in a technique called PERT/CPM, new combinations of approaches are discussed. Certain assumptions inherent to PERT and often wrong are not made by the critical chain approach.
AFRIKAANSE OPSOMMING: In hierdie artikel word tradisionele projekbestuurbenaderings soos PERT en CPM asook projekversnelling en stelselbenaderings, naamlik gelyktydige ingenieurswese, en kritiekeketting-ondersoek met betrekking tot die bydrae wat elk tot die versnelling van die uitvoeringsfase van ingenieursprojekte kan lewer. Elk van hierdie benaderings kan ‘n spesifieke bydrae tot die versnelling van projekte lewer. Kombinasies, elk bestaande uit twee verskillende benaderings, word geëvalueer. Terwyl PERT en CPM reeds baie jare lank in kombinasie gebruik word, word nuwe kombinasies ook hier bespreek. Sekere aannames inherent aan die PERT-benadering is dikwels foutief. Hierdie aannames word nie deur die kritieke-ketting-benadering gemaak nie.
Macias, J. A.
2012-01-01
Project-based learning is one of the main successful student-centered pedagogies broadly used in computing science courses. However, this approach can be insufficient when dealing with practical subjects that implicitly require many deliverables and a great deal of feedback and organizational resources. In this paper, a worked e-portfolio is…
Balancing uncertainty of context in ERP project estimation: an approach and a case study
Daneva, Maia
2010-01-01
The increasing demand for Enterprise Resource Planning (ERP) solutions as well as the high rates of troubled ERP implementations and outright cancellations calls for developing effort estimation practices to systematically deal with uncertainties in ERP projects. This paper describes an approach -
A human rights based approach to project induced displacement and resettlement
van der Ploeg, Lidewij; Vanclay, Frank
2017-01-01
AbstractRespecting, protecting and fulfilling human rights must become more prominent in both the processes and outcomes of resettlement. We have developed a Human Rights-Based Approach to Resettlement for use by project operators, rights holders and governments so that they can better understand
A human rights based approach to project induced displacement and resettlement
van der Ploeg, Lidewij; Vanclay, Frank
2017-01-01
Respecting, protecting and fulfilling human rights must become more prominent in both the processes and outcomes of resettlement. We have developed a Human Rights-Based Approach to Resettlement for use by project operators, rights holders and governments so that they can better understand what the
Gryparis, A; Forsberg, B; Katsouyanni, K; Analitis, A; Touloumi, G; Schwartz, J; Samoli, E; Medina, S; Anderson, HR; Niciu, EM; Wichmann, HE; Kriz, B; Kosnik, M; Skorkovsky, J; Vonk, JM; Dortbudak, Z
2004-01-01
In the Air Pollution and Health: A European Approach (APHEA2) project, the effects of ambient ozone concentrations on mortality were investigated. Data were collected on daily ozone concentrations, the daily number of deaths, confounders, and potential effect modifiers from 23 cities/areas for at
Harada, Violet H.
2016-01-01
This paper reports on a professional development initiative that targeted teams of teachers and librarians working with high school students on strengthening an inquiry approach to capstone projects. While much has been written about student-focused models for information search and use, little has been reported on how training for the…
Meaningful Learning in the Teaching of Culture: The Project Based Learning Approach
Kean, Ang Chooi; Kwe, Ngu Moi
2014-01-01
This paper reports on a collaborative effort taken by a team of three teacher educators in using the Project Based Learning (PBL) approach in the teaching of Japanese culture with the aim to investigate the presence of actual "meaningful learning" among 15 students of a 12-Week Preparatory Japanese Language course under a teacher…
Planning-in-Action: An Innovative Approach to Human Development. The Hunger Project.
Community Development Journal, 1991
1991-01-01
The Hunger Project in India used a strategic planning-in-action approach that involved (1) reaching a common understanding; (2) creating a strategic intent; (3) choosing social indicators; (4) identifying strategic objectives; (5) empowering leadership; (6) identifying immediate action steps; and (7) sustaining the action. (SK)
Implementing the Project Approach: A Case Study of Hybrid Pedagogy in a Hong Kong Kindergarten
Chen, Jennifer J.; Li, Hui; Wang, Jing-ying
2017-01-01
The Project Approach has been promoted in Hong Kong kindergartens since the 1990s. However, the dynamic processes and underlying mechanisms involved in the teachers' implementation of this pedagogical method there have not yet been fully investigated. This case study of one typical kindergarten in Hong Kong documented how and why eight teachers…
BlueSky ATC Simulator Project : An Open Data and Open Source Approach
Hoekstra, J.M.; Ellerbroek, J.
2016-01-01
To advance ATM research as a science, ATM research results should be made more comparable. A possible way to do this is to share tools and data. This paper presents a project that investigates the feasibility of a fully open-source and open-data approach to air traffic simulation. Here, the first of