1994 Polanyi Award Lecture Concept of active electrons in chemistry

1995 ◽  
Vol 73 (5) ◽  
pp. 619-628 ◽  
Author(s):  
Sigeru Huzinaga
Keyword(s):  
Solid State ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
Computational Method ◽  
Computational Accuracy ◽  
The Core ◽  
Way Of Thinking

The notion of division between active and dormant electrons has been well received and widely used in the chemists' way of thinking. The core–valence separation in atoms is the best-known example. This paper describes a theoretical and computational method called the model potential method, which deals only with active electrons in molecular and solid state calculations. The method is capable of reaching computational accuracy of testing the validity of the separation of active and dormant electrons in individual cases. Keywords: separability of electrons, model potential method, valence orbitals, relativistic effects.

The abinitio model potential method. Cowan–Griffin relativistic core potentials and valence basis sets from Li (Z = 3) to La (Z = 57)

1992 ◽  
Vol 70 (2) ◽  
pp. 409-415 ◽  
Author(s):  
Zoila Barandiarán ◽  
Luis Seijo
Keyword(s):  
Mass Velocity ◽  
Alkaline Earth ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
Basis Sets ◽  
Relativistic Model ◽  
Model Potentials ◽  
Valence Basis Sets ◽  
Potential Basis

A comprehensive tabulation of Cowan–Griffin relativistic abinitio core model potentials and valence basis sets corresponding to the Cowan–Griffin abinitio model potential method is presented. It includes those for the elements from Li (Z = 3) to La (Z = 57), the alkaline M+ and alkaline earth M2+ cations, and for the halogen X− anions. Molecular results are presented in order to test the potentials and basis sets and to estimate the extent of the mass–velocity and Darwin relativistic effects considered within the method, which lie within the expected margins. Keywords: relativistic, model potential, effective core potential, basis sets, abinitio.

Theoretical study of the deformation densities of d electrons in K2[PdCl6] and K2[PtCl6] crystals

1996 ◽  
Vol 52 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Y. Sakai ◽  
T. Oshibe ◽  
E. Miyoshi
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Method ◽  
Relativistic Effects ◽  
Potential Method ◽  
Model Potential ◽  
X Ray Diffraction ◽  
Hartree Fock ◽  
Density Maps ◽  
Electron Deficiency ◽  
Configuration Interaction Calculations

Aspherical distributions of the d electrons in dipotassium palladium hexachloride, K2[PdCl6], and dipotassium platinum hexachloride, K2[PtCl6], crystals were analyzed by theoretical calculations. Hartree–Fock and configuration interaction calculations were performed for [PdCl6]2− and [PtCl6]2− with and without taking into account the Madelung potentials, using a model potential method. The major relativistic effects were incorporated in the model potentials for Pd and Pt. The deformation-density maps calculated were similar to those given by the X-ray diffraction method. The theoretical result suggested that the positive peaks on the threefold axes and the negative peaks on the metal—Cl bond axis correspond to the excess d electrons (4d of Pd and 5d of Pt) in the t 2g (dxy, dxz, dyz ) orbitals and the electron deficiency in the eg (dz 2,dx 2− y 2) orbitals, respectively. The positive and negative peak heights were calculated to be +1.8 and −0.8 e Å−3 for [PdCl6]2− and +1.2 and −0.6 e Å−3 for [PtCl6]2−. The effective charges and effective radii of Pd and Pt, and the number of electrons in the t 2g , eg and t 1u orbitals, were calculated by direct integration. The effects of the Madelung potential and electron correlation on the charge distributions of [PdCl6]2− and [PtCl6]2− were also analyzed.

Unprecedented Hexa- and Undecanuclear Frameworks of Two New Tin(IV) Oxo Clusters Resulting from Partial Debenzylation Reactions

2010 ◽  
Vol 65 (11) ◽  
pp. 1293-s1308 ◽  
Author(s):  
Laurent Plasseraud ◽  
Hélène Cattey ◽  
Philippe Richard
Keyword(s):  
Solid State ◽  
1H Nmr Spectroscopy ◽  
Trifluoromethanesulfonic Acid ◽  
Synthetic Route ◽  
State Structure ◽  
X Ray Diffraction ◽  
Neutral Cluster ◽  
Broad Resonance ◽  
X Ray ◽  
The Core

A new and facile synthetic route to the known neutral cluster ((PhCH2)2SnO)6[((PhCH2)2SnOH)2- (CO3)]2 (2) as well as its reactivity toward trifluoromethanesulfonic acid (HO3SCF3, TfOH) are reported. The solid-state structure of the new solvate 2·6C7H8 has been determined by single-crystal X-ray diffraction. The core of 2 can be described as a pair of coplanar pentanuclear [(PhCH2)2SnO]5 ladders bridged at their ends by two carbonate groups. Successive additions of TfOH to a suspension of 2 in CD3CN were monitored by 119Sn{1H} NMR spectroscopy showing the transformation of the fingerprint of 2 (δ = −244, −246, −306 ppm), via new upfield signals, to a final broad resonance located at δ = −474 ppm. Thereafter, two unprecedented ionic monobenzyltin(IV) oxo clusters, 3 and 4, resulting from a debenzylation reaction and exhibiting unusual hexa- and undecanuclear frameworks, respectively, have been isolated as single crystals.

Calculation of Pairwise Effective Potentials in the Disordered Ni-22.5at.%Fe Alloy Using Model Potential Method with Account of Size Effect

2021 ◽  
Vol 323 ◽  
pp. 125-129
Author(s):  
Valentin Silonov ◽  
Lkhamsuren Enkhtor
Keyword(s):  
Size Effect ◽  
Short Range ◽  
Short Range Order ◽  
Potential Method ◽  
Model Potential ◽  
Order Parameters ◽  
Range Order ◽  
Disorder Phase Transition ◽  
Effective Potentials ◽  
Atomic Displacements

Pairwise effective potentials in first seventeen shells of the Ni-22.5at.%Fe alloy are calculated using model potential method with account of the linear size effect. Using obtained values of pairwise effective potentials, the short range order parameters on the first seventeen shells of alloy are calculated by Krivoglaz-Clapp-Moss method. The calculated values ​​of the short-range order parameters were fitted to the experimental values ​​by varying the parameters of static atomic displacements. Reliable value of critical temperature of order-disorder phase transition in Ni-22.5at.%Fe alloy was calculated using obtained meanings of pairwise effective potentials.

Prediction of Cavitation Inception Within Regions of Flow Separation

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Turbulent Flow ◽  
Flow Separation ◽  
Computational Method ◽  
Average Flow ◽  
Cavitation Inception ◽  
The Core ◽  
Good Agreement

Cavitation within regions of flow separation appears in drifting vortices. A two-part computational method is employed for prediction of cavitation inception number there. The first part is an analysis of the average flow in separation regions without consideration of an impact of vortices. The second part is an analysis of equilibrium of the bubble within the core of a vortex located in the turbulent flow of known average characteristics. Computed cavitation inception numbers for axisymmetric flows are in the good agreement with the known experimental data.

scholarly journals The ab initio model potential method with the spin-free relativistic scheme by eliminating small components Hamiltonian

2001 ◽  
Vol 114 (14) ◽  
pp. 6000-6006 ◽  
Author(s):  
Kyosuke Motegi ◽  
Takahito Nakajima ◽  
Kimihiko Hirao ◽  
Luis Seijo
Keyword(s):  
Ab Initio ◽  
Potential Method ◽  
Model Potential

scholarly journals The Immense House of Postcards

1970 ◽  
Vol 21 (1) ◽  
pp. 43-71
Author(s):  
Hanoch Ben-Pazi
Keyword(s):  
Jacques Derrida ◽  
Emmanuel Levinas ◽  
Vantage Point ◽  
Cultural Significance ◽  
Ethical Thought ◽  
Religious Traditions ◽  
The Core ◽  
Textual Tradition ◽  
The Subject ◽  
Way Of Thinking

The subject of tradition engaged both Emmanuel Lévinas and Jacques Derrida in many of their writings, which explore both the philosophical and cultural significance of tradition and the particular significance of the latter in a specifically Jewish context. Lévinas devoted a few of his Talmudic essays to the subject, and Derrida addressed the issue from the perspective of different philosophical and religious traditions. This article uses the writings of these two thinkers to propose a new way of thinking about the idea of tradition. At the core of its inquiry lie the paradigm of the letter and the use of this metaphor as a means of describing the concept of tradition. Using the phenomenon of the letter as a vantage point for considering tradition raises important points of discussion, due to both the letter’s nature as a text that is sent and the manifest and hidden elements it contains. The focus of this essay is the phenomenon of textual tradition, which encompasses different traditions of reading and interpreting texts and a grasp of the horizon of understanding opened up in relation to the text through its many different interpretations. The attention paid here to the actions of individuals serves to highlight the importance of the interpersonal realm and of ethical thought.

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