Related Experiment Videos
AM1* parameters for phosphorus, sulfur and chlorine
Paul Winget1, Anselm H C Horn, Cenk Selçuki
1Computer-Chemie-Centrum, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen, Germany.
Journal of Molecular Modeling
|September 5, 2003
Summary
A new computational method, AM1*, enhances the Austin Model 1 (AM1) technique for molybdenum compounds. This improved semiempirical molecular orbital method offers greater accuracy for elements like phosphorus, sulfur, and chlorine in molybdenum-containing molecules.
Area of Science:
- Computational Chemistry
- Quantum Chemistry
- Theoretical Chemistry
Background:
- The Austin Model 1 (AM1) is a widely used semiempirical method for molecular orbital calculations.
- Existing AM1 parameters may not accurately represent complex molecules, particularly those containing heavier elements.
Purpose of the Study:
- To introduce an extension of the AM1 method, termed AM1*, designed for improved accuracy in calculations.
- To reparameterize specific elements and core interactions within the AM1 framework.
Main Methods:
- The AM1* method retains AM1 parameters for H, C, N, O, and F.
- Elements P, S, and Cl are reparameterized using a d-orbital basis set and modified core-core parameters.
- Incorporates Voityuk and Rösch's AM1(d) parameters, with new core-core parameters for Mo-P, Mo-S, and Mo-Cl interactions.
Main Results:
- AM1* yields identical results to AM1 for compounds lacking P, S, or Cl.
- AM1* produces results consistent with AM1(d) for molybdenum compounds containing only H, C, N, O, and F.
- Significant differences are observed for molybdenum compounds that include P, S, or Cl, indicating improved treatment.
Conclusions:
- AM1* represents a valuable refinement of the AM1 semiempirical method.
- The new parameterization enhances the accuracy of molecular orbital calculations for a broader range of molybdenum-containing compounds.
- Further analysis of AM1* performance and typical errors is warranted.