Quantum Chemical Approaches: Semiempirical Molecular Orbital and Hybrid Quantum Mechanical/Molecular Mechanical Techniques

When cited, please refer to: R. A. Bryce and I. H. Hillier. Current Pharmaceutical Design 2014, 20, 3293-3302. Quantum Chemical Approaches: Semiempirical molecular orbital and hybrid quantum mechanical/molecular mechanical techniques

Semiempirical Quantum Mechanical Methods for Noncovalent Interactions for Chemical and Biochemical Applications

Semiempirical (SE) methods can be derived from either Hartree-Fock or density functional theory by applying systematic approximations, leading to efficient computational schemes that are several orders of magnitude faster than ab initio calculations. Such numerical efficiency, in combination with modern computational facilities and linear scaling algorithms, allows application of SE methods to ...

Semiempirical Quantum-Chemical Orthogonalization-Corrected Methods: Theory, Implementation, and Parameters.

Semiempirical orthogonalization-corrected methods (OM1, OM2, and OM3) go beyond the standard MNDO model by explicitly including additional interactions into the Fock matrix in an approximate manner (Pauli repulsion, penetration effects, and core-valence interactions), which yields systematic improvements both for ground-state and excited-state properties. In this Article, we describe the underl...

Machine Learning of Parameters for Accurate Semiempirical Quantum Chemical Calculations

We investigate possible improvements in the accuracy of semiempirical quantum chemistry (SQC) methods through the use of machine learning (ML) models for the parameters. For a given class of compounds, ML techniques require sufficiently large training sets to develop ML models that can be used for adapting SQC parameters to reflect changes in molecular composition and geometry. The ML-SQC appro...

Quantum mechanical proton range in human body

Introduction: Proton therapy delivers radiation to tumor tissue in a much more confined way than conventional photon therapy thus allowing the radiation oncologist to use a greater dose while still minimizing side.   Materials and Methods: protons release most of their energy within the tumor region. As a result, the treating physician can potentially give an...