Michael W Schmidt

Publications (40)71.62 Total impact

• Article: Synthesis, structure, and bonding properties of 5-carbaphosphatranes: a new class of main group atrane.

  Junji Kobayashi, Kei Goto, Takayuki Kawashima, Michael W Schmidt, Shigeru Nagase
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  ABSTRACT: 1-Hydro-5-carbaphosphatrane (1) and 1-methyl-5-carbaphosphatrane (2), the first 5-carbon analogues of phosphatranes, were synthesized by a demethylation reaction of cyclic phosphinate 3. X-ray analysis revealed that 1 has a typical trigonal bipyramidal structure with hydrogen and carbon atoms at the apical position and three oxygen atoms at the equatorial positions, indicating that 1 is a phosphorane in the perfectly "anti-apicophilic" arrangement. Apical P-C and P-H bond lengths were 1.921(2) and 1.38(2) A, respectively. The (1)J(PH) value of 1 and the (1)J(PC)(P-CH(3)) value of 2 were 852 and 215 Hz, respectively, which are extraordinarily large for the apical coupling constants of phosphoranes, but close to those of the reported phosphatranes with a 5-nitrogen atom. IR and Raman spectra are also reported. Force constant calculations indicate the transannular bond in carbaphosphatrane is 3 times stronger than in silatrane, due to its covalent character.
  Journal of the American Chemical Society 05/2002; 124(14):3703-12. · 9.91 Impact Factor
• Article: A theoretical study of some reactions of silicoacetylide anion

  Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Article: Ab initio studies of HXYPO and XYPOH molecules

  Mark S. Gordon, Jerry A. Boatz, Michael W. Schmidt
  04/2002;
• Article: Concerted dihydrogen exchange between ethane and ethylene. SCF and FORS calculations of the barrier

  David F. Feller, Michael W. Schmidt, Klaus Ruedenberg
  04/2002;
• Article: Electronic structure of the phosphoryl and thiophosphoryl bonds

  Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Article: Intraatomic correlation correction in the FORS model

  Brenda Lam, Michael W. Schmidt, Klaus Ruedenberg
  04/2002;
• Article: Ground-state potential energy surface of phosphine oxide

  Jerry A. Boatz, Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Article: Theoretical Investigation of Azaphosphatrane Bases

  Theresa L. Windus, Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Article: Does methane invert through square planar?

  Mark S. Gordon, Michael W. Schmidt
  04/2002;
• Article: Structural Trends in Silicon Atranes

  Michael W. Schmidt, Theresa L. Windus, Mark S. Gordon
  04/2002;
• Article: Observability of cubic octaphosphorus

  Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Article: .pi.-Bond strengths in diphosphenes (HP:PH, H2P:P), phosphinimine, and diimine

  Michael W. Schmidt, Mark S. Gordon
  04/2002;
• Conference Proceeding: Performance and Implementation of Distributed Data CPHF and SCF Algorithms.

  Yuri Alexeev, Michael W. Schmidt, Theresa L. Windus, Mark S. Gordon, Ricky A. Kendall
  2002 IEEE International Conference on Cluster Computing (CLUSTER 2002), 23-26 September 2002, Chicago, IL, USA; 01/2002
• Article: Ga−Ga Multiple Bond in Na2[Ar*GaGaAr*] (Ar* = C6H3-2,6-(C6H2-2,4,6-i-Pr3)2)

  Nozomi Takagi, Michael W. Schmidt, Shigeru Nagase
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  ABSTRACT: Theoretical calculations are carried out to investigate the Ga−Ga bond in the title compound, whose description as the first example of a triple bond between group 13 elements has sparked considerable interest. The short Ga−Ga bond length is found to be the result of several factors, including Na−terphenyl and terphenyl−terphenyl ionic interactions, direct Ga−Na−Ga bridge bonding, and adjustments in the C−Ga−Ga angles due to the steric requirements of the i-Pr groups on the bulky m-terphenyl ligands.
  03/2001;
• Article: Cubic fuels?

  Michael W. Schmidt, Mark S. Gordon, Jerry A. Boatz
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  ABSTRACT: The cubic molecules C4O4, N8, and Si8R8 are considered as possible high-energy propellants. The potential energy surface minimum for C4O4 is found to be incapable of supporting any bound vibrational levels. N8's decomposition to 4 N2 is mapped in detail, but the initial barrier of its rather complicated dissociation is too modest to allow hope for its handling in bulk quantity. Si8H8 is found to be the most promising additive among the four R's considered, but simulation of its combustion in an LH2/LOX rocket gives only a 6-s specific impulse enhancement. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 76: 434–446, 2000
  International Journal of Quantum Chemistry 02/2000; 76(3):434 - 446. · 1.36 Impact Factor
• Article: Approximate second order method for orbital optimization of SCF and MCSCF wavefunctions

  Galina Chaban, Michael W. Schmidt, Mark S. Gordon
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  ABSTRACT: A quasi-Newton method involving a diagonal guess orbital hessian with iterative updates has been proposed recently by Almlof for the optimization of closed shell self-consistent field (SCF) wavefunctions. The technique is extended in the present work to more general wavefunctions, ranging from open shell SCF through multiconfigurational SCF. A number of examples are presented to show that convergence for closed and open shell SCF rivals conventional direct inversion in the iterative subspace (DIIS). For multiconfigurational SCF wavefunctions, the method presented here requires more iterations than an exact second order program, but since each iteration is substantially faster, leads to a more efficient overall program.
  Theoretical Chemistry Accounts 01/1997; 97(1):88-95. · 2.16 Impact Factor
• Article: Parallel algorithm for integral transformations and GUGA MCSCF

  Theresa L. Windus, Michael W. Schmidt, Mark S. Gordon
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  ABSTRACT: An algorithm for the parallelization of the atomic to molecular integral transformation and the subsequent steps in a GUGA based MCSCF calculation is presented. Timing data shows that the transformation and diagonalization steps are well parallelized and that several of the other portions of the MCSCF code are moderately parallel. Remaining sequential bottlenecks are identified.
  Theoretical Chemistry Accounts 08/1994; 89(1):77-88. · 2.16 Impact Factor
• Article: Chemical binding and electron correlation in diatomic molecules as described by the FORS model and the FORS-IACC model

  Michael W. Schmidt, M. T. Brenda Lam, Stephen T. Elbert, Klaus Ruedenberg
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  ABSTRACT: Using the model of the Full Optimized Reaction Space including the Intra-Atomic Correlation Correction, binding energies and other electronic properties have been calculated for several states of a number of diatomic molecules. In most cases this theoretical approach yields results agreeing with experimental values to within 0.2 eV. The investigation covers the molecules BH, CH, NH, OH, FH, N2, O2, F2.
  Theoretical Chemistry Accounts 01/1985; 68(1):69-86. · 2.16 Impact Factor
• Article: Are atoms intrinsic to molecular electronic wavefunctions? III. Analysis of FORS configurations

  Klaus Ruedenberg, Michael W. Schmidt, Mary M. Gilbert, S.T. Elbert
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  ABSTRACT: The interpretation of configurational bases in the full reaction space depends on the type of FORS MOs from which they are generated. Configurations constructed from atom-adapted FORS MOs have the character of valence bond structures and can be transformed into antisymmetrized products of atomic state functions. Configurations based on natural FORS MOs can be used to advantage to generate that part of the full reaction space which dominates the orbital optimization. Configurational mixing in the full reaction space can be predicted using the minimal basis set of the free-atom SCF AOs. Illustrative examples are given. The FORS model can be improved through the intra-atomic correlation correction.
  Chemical Physics.
• Source

  Available from: scc.acad.bg

  Article: Coupled cluster algorithms for networks of shared memory parallel processors

  Jonathan L. Bentz, Ryan M. Olson, Mark S. Gordon, Michael W. Schmidt, Ricky A. Kendall
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  ABSTRACT: As the popularity of using SMP systems as the building blocks for high performance supercomputers increases, so too increases the need for applications that can utilize the multiple levels of parallelism available in clusters of SMPs. This paper presents a dual-layer distributed algorithm, using both shared-memory and distributed-memory techniques to parallelize a very important algorithm (often called the “gold standard”) used in computational chemistry, the single and double excitation coupled cluster method with perturbative triples, i.e. CCSD(T). The algorithm is presented within the framework of the GAMESS [M.W. Schmidt, K.K. Baldridge, J.A. Boatz, S.T. Elbert, M.S. Gordon, J.J. Jensen, S. Koseki, N. Matsunaga, K.A. Nguyen, S. Su, T.L. Windus, M. Dupuis, J.A. Montgomery, General atomic and molecular electronic structure system, J. Comput. Chem. 14 (1993) 1347–1363]. (General Atomic and Molecular Electronic Structure System) program suite and the Distributed Data Interface [M.W. Schmidt, G.D. Fletcher, B.M. Bode, M.S. Gordon, The distributed data interface in GAMESS, Comput. Phys. Comm. 128 (2000) 190]. (DDI), however, the essential features of the algorithm (data distribution, load-balancing and communication overhead) can be applied to more general computational problems. Timing and performance data for our dual-level algorithm is presented on several large-scale clusters of SMPs.
  Computer Physics Communications.