title: AM1* parameters for aluminum, silicon, titanium and zirconium.
abstract: Our extension of the AM1 semiempirical molecular orbital technique, AM1*, has been parameterized for the elements Al, Si, Ti and Zr. The basis sets for all four metals contain a set of d-orbitals. Thus, AM1* parameters are now available for H, C, N, O and F (which use the original AM1 parameters), Al, Si, P, S, Cl, Ti, Mo and Zr. Special attention was paid to reproducing homolytic and heterolytic bond-dissociation energies correctly. Such bond-energy data help to avoid eccentricities in the parameterization caused by inaccurate experimental heats of formation. The performance and typical errors of AM1* for the newly parameterized elements are discussed. Generally, the new method performs less well than established techniques for heats of formation but considerably better for the heats of reaction.
authors.affiliation: Computer-Chemie-Centrum, Friedrich-Alexander Universität Erlangen-Nürnberg, Nägelsbachstrasse 25, 91052 Erlangen, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Winget
authors.forename: Timothy
authors.initials: T
authors.lastname: Clark
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D006358:Hot Temperature; D007477:Ions / Q000737:chemistry; D008956:Models, Chemical; D012825:Silicon / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
chemical_list: D007477:Ions; D015040:Zirconium; D000535:Aluminum; D014025:Titanium; D012825:Silicon