Optimization of Parameters for Semiempirical Methods 2. Applications

Abstract

MNDO/AM1-type parameters for twelve elements have been optimized using a newly developed method for optimizing parameters for semiempirical methods. With the new method, MNDO-PM3, the average difference between the predicted heats of formation and experimental values for 657 compounds is 7.8 kcal/mol, and for 106 hypervalent compounds, 13.6 kcal/mol. For MNDO the equivalent difference are 13.9 and 75.8 kcal/mol, while those for AM1, in which MNDO parameters are used for aluminum, phosphorus, and sulfur, are 12.7 and 83.1 kcal/mol, respectively. Average errors for ionization potentials, bond angles, and dipole moments are intermediate between those for MNDO and AM1, while errors in bond lengths are slightly reduced.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1989
Accession Number
ADA209386

Entities

People

  • James J. Stewart

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Alkanes
  • Alkenes
  • Chemical Synthesis
  • Chemistry
  • Cyanides
  • Cyclic Hydrocarbons
  • Nitrogen Oxides
  • Organic Chemistry

Fields of Study

  • Chemistry

Readers

  • Computer Programming and Software Development.
  • Quantum Chemistry