Open Access. Powered by Scholars. Published by Universities.®
- Publication
Articles 1 - 9 of 9
Full-Text Articles in Entire DC Network
Fast Method For Calculating The Self-Consistent Electronic Structure Of Random Alloys, Duane D. Johnson, F. J. Pinski, G. M. Stocks
Fast Method For Calculating The Self-Consistent Electronic Structure Of Random Alloys, Duane D. Johnson, F. J. Pinski, G. M. Stocks
Duane D. Johnson
We describe a computationally efficient method for performing self-consistent-field calculations of the electronic structure of random solid-solution alloys within the multiple-scattering coherent-potential-approximation formalism (KKR-CPA). We utilize a cluster method for solving the KKR-CPA equations and integrate along a contour in the complex-energy plane to reconstruct the single-site electronic densities.
Theoretical Study Of Silylene Insertion Into N-H, O-H, F-H, P-H, S-H, And Cl-H Bonds, Krishnan Raghavachari, Jayaraman Chandrasekhar, Mark S. Gordon, Ken Dykema
Theoretical Study Of Silylene Insertion Into N-H, O-H, F-H, P-H, S-H, And Cl-H Bonds, Krishnan Raghavachari, Jayaraman Chandrasekhar, Mark S. Gordon, Ken Dykema
Mark S. Gordon
The potential energy surfaces for the insertion reactions of silylene into NH3, Hp, HF, PH3, H2S, and HCl have been characterized in detail by using ab initio molecular orbital theory, including electron correlation and zero-point corrections. All the interactions involve the initial formation of a donor-acceptor complex followed by a proton shift via an unsymmetrical high-energy transition state. The binding energies of the complexes as well as the rearrangement barriers for the hydrogen migration of these complexes to give the normal valent compounds have been calculated in all cases. The complex between SiH2 and NH3 exists in a deep minimum …
Ab Initio Study Of The Insertions Of Methylene And Silylene Into Methane, Silane, And Hydrogen, Mark S. Gordon, David R. Gano
Ab Initio Study Of The Insertions Of Methylene And Silylene Into Methane, Silane, And Hydrogen, Mark S. Gordon, David R. Gano
Mark S. Gordon
The transition states for several insertion reactions have been determined at the 3-21G level of theory. While the insertions of CH2 and SiH2 into the CH and SiH bonds of methane and silane, respectively, all have nonzero SCF barriers, only the insertion of silylene into methane retains a nonzero barrier when third-order Moller-Plesset perturbation theory corrections are included with the 6-31G* basis set. The intrinsic reaction coordinates for the carbene and silylene insertions into methane are used to provide a pictorial view of these reactions and to relate the calculations to earlier studies. The insertion of silylene into H2 is …
Ab Initio Studies Of Hxypo And Xypoh Molecules, Mark S. Gordon, Jerry A. Boatz, Michael W. Schmidt
Ab Initio Studies Of Hxypo And Xypoh Molecules, Mark S. Gordon, Jerry A. Boatz, Michael W. Schmidt
Mark S. Gordon
Molecular orbital calculations have been carried out on a sequence of HXYPOH molecules, with X and Y = H, CH3, NH2, OH, OCH3, and F. The molecular structures are predicted with the ST0-2G* basis set. For the prediction of energies of isomerization to XYPOH species, single-point 3-21G* and 6-31G* calculations were used. The molecular dissociation energies of HXYPO to HPO + XY and to XPO + HY were calculated by augmenting the latter two basis sets with MP2 and MP3 perturbation corrections.
Hydrogen Abstractions By Triplet Methylene And Silylene, Mark S. Gordon
Hydrogen Abstractions By Triplet Methylene And Silylene, Mark S. Gordon
Mark S. Gordon
While the most common reactions of singlet methylenes are insertions into Y -H or multiple bonds, 1-3 triplet methylenes tend to abstract hydrogens from Y -H bonds. 1·2 Singlet silylenes are also known to insert,4-6 while little is known about the corresponding triplets. Several theoretical papers have been devoted to analyses of the insertions of singlet CH/-12 and SiHP-15 into a variety of bonds and the abstractions of hydrogen from H216-20 and CH417 by triplet methylene. Ab initio calculations including correlation predict that carbenes insert into Y-H9•11 ·12·15 bonds with no barrier, in agreement with the prevailing experimental evidence;1·2 however, …
Theoretical Studies Of Cyclic C2si2h4 Molecules, Thomas A. Holme, Mark S. Gordon, Satoshi Yabushita, Michael W. Schmidt
Theoretical Studies Of Cyclic C2si2h4 Molecules, Thomas A. Holme, Mark S. Gordon, Satoshi Yabushita, Michael W. Schmidt
Mark S. Gordon
Thirteen cyclic C2Si2H4 isomers, including disilatetrahedrane and the disilacyclobutadienes, have been studied by using ab initio quantum mechanics. At the MP3/6-31G* / /3-21G level of computation, the silyl-substituted silacyclopropenylidene is found to be the most stable. Disilatetrahedrane is quite high on the energy surface, and the two possible planar 1,2-disilacyclobutadienes do not represent minima on this surface. Planar 1,3-disilacyclobutadiene is a stable structure and exhibits significant diradical character.
Theoretical Studies Of Polyvinyl-Substituted Carbenium And Silylenium Ions, Thanh Truong, Mark S. Gordon, Philip Boudjouk
Theoretical Studies Of Polyvinyl-Substituted Carbenium And Silylenium Ions, Thanh Truong, Mark S. Gordon, Philip Boudjouk
Mark S. Gordon
Ab initio (ST0-2G and 3-21G) calculations have been performed to analyze the ability of one, two, and three vinyl groups to stabilize the CH3 + and SiH3 + ions. Vinyl groups appear to be quite effective at stabilizing the positive charge on the silylenium ion, and successive vinylization preferentially stabilizes the silicon relative to the carbon ion.
Theoretical Study Of Methylsilanone And Five Of Its Isomers, Mark S. Gordon, Clayton George
Theoretical Study Of Methylsilanone And Five Of Its Isomers, Mark S. Gordon, Clayton George
Mark S. Gordon
By use of 3-21G SCF geometries and relative energies from MP3/6-31G* wave functions, methylsilanone has been found to be the most stable of the six isomers investigated. The relative stabilities of methylsilanone and silylformaldehyde are rationalized by the metathesis reaction H 2Si0 + C2H4 .... H 2CO + H 2CSiH4. This reaction is used to suggest that the C=O bond is about 10 kcaljmol stronger than Si=O.
Structure, Bonding, And Internal Rotation In Phosphine Oxide (H3po), Hydroxyphosphine (H2poh), And Hydroxyfluorophosphine (Hfpoh), Michael W. Schmidt, Satoshi Yabushita, Mark S. Gordon
Structure, Bonding, And Internal Rotation In Phosphine Oxide (H3po), Hydroxyphosphine (H2poh), And Hydroxyfluorophosphine (Hfpoh), Michael W. Schmidt, Satoshi Yabushita, Mark S. Gordon
Mark S. Gordon
The fundamental nature of the PO bond is reexamined by using ab initio (3-21G* and 6-31G*) wave functions and energy-localized orbitals. The bond is best described as a dative single bond augmented by 71' back-donation from the oxygen lone pairs. The isomerization pathway from H3PO to H2POH is followed by using the intrinsic reaction coordinate and localized orbitals. The latter, more stable, isomer has two forms, cis and trans, which are nearly equal in energy. The internal rotation barriers in this molecule and in HFPOH are examined with a Fourier analysis and compared with their nitrogen analogues. The major differences …