Hybrid Quantum and Molecular Mechanical Simulations: An Alternative Avenue to Solvent Effects in Organic Chemistry

TL;DR: The Hellmann-Feynman theorem as mentioned in this paper states that the interactions between solutes and solvents are Coulombic in nature and therefore fall into the same category as those that govern molecular recognition processes, the formation and properties of liquids and solids, physical adsorption, etc.

TL;DR: This study involves the intramolecular proton transfer process on a thymine nucleobase between N3 and O2 atoms and explores a mechanism for the PT assisted by hexacoordinated divalent metals cations, namely Mg2+, Zn2+.

TL;DR: This unit expands an accompanying overview unit (UNIT ) by discussing methods used to treat the energy and sample representative configurations by placing emphasis on molecular mechanics and empirical force fields.

TL;DR: It is demonstrated that DCMB is capable of providing accurate prediction of molecular geometries, total energies, and vibrational frequencies of molecules of general interest and holds the promise for a routine geometry optimization of large complex systems.

TL;DR: The CHARMM (Chemistry at Harvard Macromolecular Mechanics) as discussed by the authors is a computer program that uses empirical energy functions to model macromolescular systems, and it can read or model build structures, energy minimize them by first- or second-derivative techniques, perform a normal mode or molecular dynamics simulation, and analyze the structural, equilibrium, and dynamic properties determined in these calculations.

TL;DR: Weiner et al. as mentioned in this paper derived a new molecular mechanical force field for simulating the structures, conformational energies, and interaction energies of proteins, nucleic acids, and many related organic molecules in condensed phases.

TL;DR: In this paper, a new parametric quantum mechanical molecular model, AM1 (Austin Model l), based on the NDDO approximation, is described, in which the major weaknesses of MNDO, in particular failure to reproduce hydrogen bonds, have been overcome without any increase in computing time.