Quantum and Molecular Mechanical Methods

Csjmhined Quantum and Molecular Mechanics Methods J. Gao, M. Thompson, Eds., American Chemical Society, Washington (1998). 

Combined Quantum and Molecular Mechanical Simulations. A recentiy developed technique is one wherein a molecular dynamics simulation includes the treatment of some part of the system with a quantum mechanical technique. This approach, QM/MM, is similar to the coupled quantum and molecular mechanical methods introduced by Warshel and Karplus (45) and at the heart of the MMI, MMP2, and MM3 programs by AUinger (60). These latter programs use quantum mechanical methods to treat the TT-systems of the stmctures in question separately from the sigma framework. 

S. Piofeta, Ji., Conformational Analysis of Aliphatic Amines by Quantum and Molecular Mechanical Methods, Pb.D. Dissertation, University of Georgia, 1978, available from University Microfilms International, Arm Arbor, Mich. 

Singh, U.C., Kollman, P.A. A combined ab initio quantum mechanical and molecular mechanical method for carrying out simulations on complex molecular systems Applications to the CH3CI 4- Cl exchange reaction and gas phase protonation of polyethers. J. Comput. Chem. 7 (1986) 718-730. 

HYBRID QUANTUM-MECHANICAL AND MOLECULAR MECHANICAL METHODS... 

Zhang Y, Lee TS, Yang W (1999) A pseudobond approach to combining quantum mechanical and molecular mechanical methods. J Chem Phys 110 46-54... 

Hawkins GD, Zhu T, Li J, Chambers CC, Giesen DJ, Liotard DA, Cramer CJ, Truhlar DG (1998) Combined quantum mechanical and molecular mechanical methods, 201-219, ACS Symposium Series 712, Oxford University Press, New York. 

I. Antes, W. Thiel, On the Treatment of Link Atoms in Hybrid Methods, in Combined Quantum Mechanical and Molecular Mechanical Methods, J. Gao, M. A. Thompson (eds), American Chemical Society, Washington, DC, 1998, pp. 50-65. 

Bash, P. A., Field, M. J. and Karplus, M. Free energy perturbation method for chemical reactions in the condensed phase a dynamical approach based on a combined quantum and molecular mechanics potential,... 

There are many computational chemistry software packages available that enable students to make and study the properties of molecules, by quantum mechanics and molecular mechanics methods. These include Gaussian, HyperChem, Spartan, and Biosym. The first four homework problems assume that the student has one of... 

Gao, J. and Thompson, M. A.. Eds., 1998. Methods and Applications of Hybrid Quantum Mechanical and Molecular Mechanical Methods, ACS Symposium Series, Vol. 712. American Chemical Society Washington. DC. 

It is worth mentioning that anew quantum mechanical and molecular mechanical method was developed by Kaminski and Jorgensen, based on the CM1A charges computed by AMSOL [61]. Results obtained with this method demonstrated the proposed approach provides results competitive with other methods for estimating solvent effects ontautomerization [137]. 

I. Antes and W. Thiel, Adjusted connection atoms for combined quantum mechanical and molecular mechanical methods, J. Phys. Chem. A, 103 (1999) 9290-9295. 

There has been a decisive evolution in the treatment of steric effects in heteroaromatic chemistry. The quantitative estimation of the role of steric strain in reactivity was first made mostly with the help of linear free energy relationships. This method remains easy and helpful, but the basic observation is that the description of a substituent by only one parameter, whatever its empirical or geometrical origin, will describe the total bulk of the substituent and not its conformationally dependent shape. A better knowledge of static and dynamic stereochemistry has helped greatly in understanding not only intramolecular but also intermolecular steric effects associated with rates and equilibria. Quantum and molecular mechanics calculations will certainly be used in the future to a greater extent. 

Bash, P.A., Field M.J. and Karplus M., Free Energy Perturbation Method for Chemical Reactions in the Condensed Phase A Dynamical Approach Based on a Combined Quantum and Molecular Mechanics Potential. J. Am. Chem.Soc. (1987) 109 8092-8094. 

Duijnen, P.Th. van, Swart M. and Grozema F., QM/MM calculation of (hyper)polarizabilities with the DRFapproach., in Hybrid Quantum Mechanical and Molecular Mechanics Methods, J.Gao and M.A. Thompson, Editors. 1999, ACS Books Washington, DC. p. 220-232. 

This presentation is structured in the following way. The first section outlines the procedure for the quantum mechanics and classical mechanics approach. The following two sections contain an overview of how to establish a density functional theory and molecular mechanics method along with the theoretical background for... 

---