Results 151 to 160 of about 10,558 (195)
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Coupled-cluster theory with simplified linear-r12 corrections: The CCSD(R12) model
The Journal of Chemical Physics, 2005A simplified singles-and-doubles linear-r12 corrected coupled-cluster model, denoted CCSD(R12), is proposed and compared with the complete singles-and-doubles linear-r12 coupled-cluster method CCSD-R12. An orthonormal auxiliary basis set is used for the resolution-of-the-identity approximation to calculate three-electron integrals needed in the linear ...
Heike, Fliegl +2 more
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Metal Science and Heat Treatment, 1966
1. The cutting qualities of tools made of R12 steel are as good as those of cutters made of the more expensive R18 steel. 2. Extensive industrial tests of R12 steel are needed in view of its utilization in industry.
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1. The cutting qualities of tools made of R12 steel are as good as those of cutters made of the more expensive R18 steel. 2. Extensive industrial tests of R12 steel are needed in view of its utilization in industry.
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Linear R12 Terms in Coupled Cluster Theory
2003Highly accurate molecular electronic energies and properties can be obtained computationally when the molecular electronic trial wave function depends explicitly on the inter-electronic distances r ij = |r i − r j | in the system. This has been known since the early days of quantum mechanics [1, 2], but it has proven very difficult to develop generally
Klopper, Wim, Noga, Jozef
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On the saturation of foF2 for R12 above 150
Advances in Space Research, 1997Abstract In the IRI model foF2 ‘saturates’ when R12 - the 12 months running mean sunspot numbers - is equal to 150. This is surprising since with increase in sunspot numbers, solar EUV flux would increase, which would enhance the ion production rate.
K.K. Mahajan +3 more
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2023
The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements. They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Multireference R12 Coupled Cluster Theory
2010In order to account for static electron correlation, the explicitly correlated coupled cluster (CC) theory based on the R12 Ansatz is formulated with respect to a multi-determinantal reference using the Brillouin – Wigner (BW) approach. Though the latter avoids appearance of the intruder states, one pays for this desired feature by the loss of size ...
Stanislav Kedžuch +3 more
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MP2-R12 calculations on the relative stability of carbocations
The Journal of Physical Chemistry, 1990The MP2-R12 method (second-order MOller-Plesset perturbation theory with linear r 12 -dependent terms) is briefly presented, and applications to the ions CH 5 + , C 2 H 3 + , C 3 H 5 + , and C 3 H 7 + are described. With the MP2-R12 method one comes rather close to the basis set limit of MP2 theory, although the MP2-R12 method does not provide ...
Klopper, Wim, Kutzelnigg, Werner
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Towards Universal R12 Consistent Basis Sets
Collection of Czechoslovak Chemical Communications, 2003Using H- and H2 as examples, it is demonstrated that parameters of the one-electron basis sets optimized for explicitly correlated R12 calculations are quite different from those developed for conventional calculations that utilize a usual configuration interaction expansion for the wavefunction.
Jozef Noga, Pierre Valiron
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An investigation of the mechanism of the R12-oil-steel reaction
Wear, 1991Abstract Past work has shown that the chemical stability of hydrocarbon lubricating oils used in closed refrigeration compressor systems containing the refrigerant CCl 2 F 2 (R12) is diminished by a chemical interaction between the oil, the R12 and the steel surfaces present in the compressor.
A. Factor, P.M. Miranda
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CID and CEPA calculations with linear r12 terms
Chemical Physics Letters, 1991Abstract Inclusion of linear r 12 -dependent terms into many-electron wavefunctions considerably speeds up the convergence to the limit of a complete basis. Here, first results of MP3-R12, CID-R12, and CEPA-R12 calculations are presented. They demonstrate that the philosophy that led to the rather successful MP2-R12-scheme is similarly effective in
Klopper, Wim +2 more
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