Semichem, Inc. — Providers of Solutions for Computational Chemistry
Semiempirical Quantum Mechanics
SAM1
- SAM1 Performance for C, H, O, N, F, Cl, Br, I
- SAM1 Performance for Si, S, P (1)
- SAM1 Literature References
SAM1 was introduced by MJS Dewar in 1993 and has been expanding since that time. It is a truly new semiempirical method, in that it replaces a key part of the AM1 / PM3 / MNDO theoretical model with a new approach. This key component is the two-electron repulsion integrals (TERIs) which are one of the basic terms in Hartree-Fock theory. Previously, this quantity was computed using a multipole expansion, but SAM1 uses a minimal gaussian basis set (with appropriate semiempirical scaling) to compute these terms directly. This has led to much improved performance over previous methods as well as access to d-orbital elements. SAM1 is currently parameterized for 13 elements and work on others is underway.
